test_upload.py

import io
import os
import re
import time
import urllib
from io import StringIO
from unittest import mock
from unittest.mock import patch

import orjson
from django.conf import settings
from PIL import Image
from urllib3 import encode_multipart_formdata
from urllib3.fields import RequestField

import zerver.lib.upload
from zerver.actions.create_realm import do_create_realm
from zerver.actions.message_send import internal_send_private_message
from zerver.actions.realm_icon import do_change_icon_source
from zerver.actions.realm_logo import do_change_logo_source
from zerver.actions.realm_settings import do_change_realm_plan_type, do_set_realm_property
from zerver.actions.user_settings import do_delete_avatar_image
from zerver.lib.avatar import avatar_url, get_avatar_field
from zerver.lib.cache import cache_get, get_realm_used_upload_space_cache_key
from zerver.lib.create_user import copy_default_settings
from zerver.lib.initial_password import initial_password
from zerver.lib.realm_icon import realm_icon_url
from zerver.lib.realm_logo import get_realm_logo_url
from zerver.lib.test_classes import UploadSerializeMixin, ZulipTestCase
from zerver.lib.test_helpers import (
    avatar_disk_path,
    get_test_image_file,
    ratelimit_rule,
    read_test_image_file,
)
from zerver.lib.upload import upload_message_attachment
from zerver.lib.upload.base import BadImageError, ZulipUploadBackend, resize_emoji, sanitize_name
from zerver.lib.upload.local import LocalUploadBackend
from zerver.lib.upload.s3 import S3UploadBackend
from zerver.lib.users import get_api_key
from zerver.models import (
    Attachment,
    Message,
    Realm,
    RealmDomain,
    UserProfile,
    get_realm,
    get_system_bot,
    get_user_by_delivery_email,
    validate_attachment_request,
)


class FileUploadTest(UploadSerializeMixin, ZulipTestCase):
    def test_rest_endpoint(self) -> None:
        """
        Tests the /api/v1/user_uploads API endpoint. Here a single file is uploaded
        and downloaded using a username and api_key
        """
        fp = StringIO("zulip!")
        fp.name = "zulip.txt"

        # Upload file via API
        result = self.api_post(self.example_user("hamlet"), "/api/v1/user_uploads", {"file": fp})
        response_dict = self.assert_json_success(result)
        self.assertIn("uri", response_dict)
        url = response_dict["uri"]
        base = "/user_uploads/"
        self.assertEqual(base, url[: len(base)])

        # Download file via API
        self.logout()
        response = self.api_get(self.example_user("hamlet"), url)
        self.assertEqual(response.status_code, 200)
        self.assertEqual(response.getvalue(), b"zulip!")

        # Files uploaded through the API should be accessible via the web client
        self.login("hamlet")
        self.assertEqual(self.client_get(url).getvalue(), b"zulip!")

    def test_mobile_api_endpoint(self) -> None:
        """
        Tests the /api/v1/user_uploads API endpoint with ?api_key
        auth. Here a single file is uploaded and downloaded using a
        username and api_key
        """
        fp = StringIO("zulip!")
        fp.name = "zulip.txt"

        # Upload file via API
        result = self.api_post(self.example_user("hamlet"), "/api/v1/user_uploads", {"file": fp})
        response_dict = self.assert_json_success(result)
        self.assertIn("uri", response_dict)
        url = response_dict["uri"]
        base = "/user_uploads/"
        self.assertEqual(base, url[: len(base)])

        self.logout()

        # Try to download file via API, passing URL and invalid API key
        user_profile = self.example_user("hamlet")

        response = self.client_get(url, {"api_key": "invalid"})
        self.assertEqual(response.status_code, 401)

        response = self.client_get(url, {"api_key": get_api_key(user_profile)})
        self.assertEqual(response.status_code, 200)
        self.assertEqual(response.getvalue(), b"zulip!")

    def test_file_too_big_failure(self) -> None:
        """
        Attempting to upload big files should fail.
        """
        self.login("hamlet")
        fp = StringIO("bah!")
        fp.name = "a.txt"

        # Use MAX_FILE_UPLOAD_SIZE of 0, because the next increment
        # would be 1MB.
        with self.settings(MAX_FILE_UPLOAD_SIZE=0):
            result = self.client_post("/json/user_uploads", {"f1": fp})
        self.assert_json_error(result, "Uploaded file is larger than the allowed limit of 0 MiB")

    def test_multiple_upload_failure(self) -> None:
        """
        Attempting to upload two files should fail.
        """
        self.login("hamlet")
        fp = StringIO("bah!")
        fp.name = "a.txt"
        fp2 = StringIO("pshaw!")
        fp2.name = "b.txt"

        result = self.client_post("/json/user_uploads", {"f1": fp, "f2": fp2})
        self.assert_json_error(result, "You may only upload one file at a time")

    def test_no_file_upload_failure(self) -> None:
        """
        Calling this endpoint with no files should fail.
        """
        self.login("hamlet")

        result = self.client_post("/json/user_uploads")
        self.assert_json_error(result, "You must specify a file to upload")

    def test_guess_content_type_from_filename(self) -> None:
        """
        Test coverage for files without content-type in the metadata;
        in which case we try to guess the content-type from the filename.
        """
        field = RequestField("file", b"zulip!", filename="somefile")
        field.make_multipart()
        data, content_type = encode_multipart_formdata([field])
        result = self.api_post(
            self.example_user("hamlet"), "/api/v1/user_uploads", data, content_type=content_type
        )
        self.assert_json_success(result)

        field = RequestField("file", b"zulip!", filename="somefile.txt")
        field.make_multipart()
        data, content_type = encode_multipart_formdata([field])
        result = self.api_post(
            self.example_user("hamlet"), "/api/v1/user_uploads", data, content_type=content_type
        )
        self.assert_json_success(result)

    # This test will go through the code path for uploading files onto LOCAL storage
    # when Zulip is in DEVELOPMENT mode.
    def test_file_upload_authed(self) -> None:
        """
        A call to /json/user_uploads should return a url and actually create an
        entry in the database. This entry will be marked unclaimed till a message
        refers it.
        """
        self.login("hamlet")
        fp = StringIO("zulip!")
        fp.name = "zulip.txt"

        result = self.client_post("/json/user_uploads", {"file": fp})
        response_dict = self.assert_json_success(result)
        self.assertIn("uri", response_dict)
        url = response_dict["uri"]
        base = "/user_uploads/"
        self.assertEqual(base, url[: len(base)])

        # In the future, local file requests will follow the same style as S3
        # requests; they will be first authenticated and redirected
        self.assertEqual(self.client_get(url).getvalue(), b"zulip!")

        # Check the download endpoint
        download_url = url.replace("/user_uploads/", "/user_uploads/download/")
        result = self.client_get(download_url)
        self.assertEqual(result.getvalue(), b"zulip!")
        self.assertIn("attachment;", result.headers["Content-Disposition"])

        # check if DB has attachment marked as unclaimed
        entry = Attachment.objects.get(file_name="zulip.txt")
        self.assertEqual(entry.is_claimed(), False)

        hamlet = self.example_user("hamlet")
        self.subscribe(hamlet, "Denmark")
        body = f"First message ...[zulip.txt]({hamlet.realm.host}{url})"
        self.send_stream_message(hamlet, "Denmark", body, "test")

        # Now try the endpoint that's supposed to return a temporary URL for access
        # to the file.
        result = self.client_get("/json" + url)
        data = self.assert_json_success(result)
        url_only_url = data["url"]
        # Ensure this is different from the original url:
        self.assertNotEqual(url_only_url, url)
        self.assertIn("user_uploads/temporary/", url_only_url)
        self.assertTrue(url_only_url.endswith("zulip.txt"))
        # The generated URL has a token authorizing the requester to access the file
        # without being logged in.
        self.logout()
        self.assertEqual(self.client_get(url_only_url).getvalue(), b"zulip!")
        # The original url shouldn't work when logged out:
        result = self.client_get(url)
        self.assertEqual(result.status_code, 403)

    def test_serve_file_unauthed(self) -> None:
        self.login("hamlet")
        fp = StringIO("zulip!")
        fp.name = "zulip_web_public.txt"

        result = self.client_post("/json/user_uploads", {"file": fp})
        url = self.assert_json_success(result)["uri"]

        with ratelimit_rule(86400, 1000, domain="spectator_attachment_access_by_file"):
            # Deny file access for non-web-public stream
            self.subscribe(self.example_user("hamlet"), "Denmark")
            host = self.example_user("hamlet").realm.host
            body = f"First message ...[zulip.txt](http://{host}" + url + ")"
            self.send_stream_message(self.example_user("hamlet"), "Denmark", body, "test")

            self.logout()
            response = self.client_get(url)
            self.assertEqual(response.status_code, 403)

            # Allow file access for web-public stream
            self.login("hamlet")
            self.make_stream("web-public-stream", is_web_public=True)
            self.subscribe(self.example_user("hamlet"), "web-public-stream")
            body = f"First message ...[zulip.txt](http://{host}" + url + ")"
            self.send_stream_message(self.example_user("hamlet"), "web-public-stream", body, "test")

            self.logout()
            response = self.client_get(url)
            self.assertEqual(response.status_code, 200)

        # Deny file access since rate limited
        with ratelimit_rule(86400, 0, domain="spectator_attachment_access_by_file"):
            response = self.client_get(url)
            self.assertEqual(response.status_code, 403)

        # Check that the /download/ variant works as well
        download_url = url.replace("/user_uploads/", "/user_uploads/download/")
        with ratelimit_rule(86400, 1000, domain="spectator_attachment_access_by_file"):
            response = self.client_get(download_url)
            self.assertEqual(response.status_code, 200)
        with ratelimit_rule(86400, 0, domain="spectator_attachment_access_by_file"):
            response = self.client_get(download_url)
            self.assertEqual(response.status_code, 403)

        # Deny random file access
        response = self.client_get(
            "/user_uploads/2/71/QYB7LA-ULMYEad-QfLMxmI2e/zulip-non-existent.txt"
        )
        self.assertEqual(response.status_code, 404)

    def test_serve_local_file_unauthed_invalid_token(self) -> None:
        result = self.client_get("/user_uploads/temporary/badtoken/file.png")
        self.assert_json_error(result, "Invalid token")

    def test_serve_local_file_unauthed_altered_filename(self) -> None:
        self.login("hamlet")
        fp = StringIO("zulip!")
        fp.name = "zulip.txt"
        result = self.client_post("/json/user_uploads", {"file": fp})
        response_dict = self.assert_json_success(result)
        url = "/json" + response_dict["uri"]

        result = self.client_get(url)
        data = self.assert_json_success(result)
        url_only_url = data["url"]

        self.assertTrue(url_only_url.endswith("zulip.txt"))
        url_only_url_changed_filename = url_only_url.split("zulip.txt")[0] + "differentname.exe"
        result = self.client_get(url_only_url_changed_filename)
        self.assert_json_error(result, "Invalid filename")

    def test_serve_local_file_unauthed_token_expires(self) -> None:
        self.login("hamlet")
        fp = StringIO("zulip!")
        fp.name = "zulip.txt"
        result = self.client_post("/json/user_uploads", {"file": fp})
        response_dict = self.assert_json_success(result)
        url = "/json" + response_dict["uri"]

        start_time = time.time()
        with mock.patch("django.core.signing.time.time", return_value=start_time):
            result = self.client_get(url)
            data = self.assert_json_success(result)
            url_only_url = data["url"]

            self.logout()
            self.assertEqual(self.client_get(url_only_url).getvalue(), b"zulip!")

        # After over 60 seconds, the token should become invalid:
        with mock.patch("django.core.signing.time.time", return_value=start_time + 61):
            result = self.client_get(url_only_url)
            self.assert_json_error(result, "Invalid token")

    def test_file_download_unauthed(self) -> None:
        self.login("hamlet")
        fp = StringIO("zulip!")
        fp.name = "zulip.txt"
        result = self.client_post("/json/user_uploads", {"file": fp})
        response_dict = self.assert_json_success(result)
        url = response_dict["uri"]

        self.logout()
        response = self.client_get(url)
        self.assertEqual(response.status_code, 403)
        self.assert_in_response("<p>You are not authorized to view this file.</p>", response)

    def test_removed_file_download(self) -> None:
        """
        Trying to download deleted files should return 404 error
        """
        self.login("hamlet")
        fp = StringIO("zulip!")
        fp.name = "zulip.txt"
        result = self.client_post("/json/user_uploads", {"file": fp})
        response_dict = self.assert_json_success(result)

        assert settings.LOCAL_UPLOADS_DIR is not None
        self.rm_tree(settings.LOCAL_UPLOADS_DIR)

        response = self.client_get(response_dict["uri"])
        self.assertEqual(response.status_code, 404)

    def test_non_existing_file_download(self) -> None:
        """
        Trying to download a file that was never uploaded will return a json_error
        """
        hamlet = self.example_user("hamlet")
        self.login_user(hamlet)
        response = self.client_get(
            f"http://{hamlet.realm.host}/user_uploads/{hamlet.realm_id}/ff/gg/abc.py"
        )
        self.assertEqual(response.status_code, 404)
        self.assert_in_response("This file does not exist or has been deleted.", response)

    def test_attachment_url_without_upload(self) -> None:
        hamlet = self.example_user("hamlet")
        self.login_user(hamlet)
        with self.assertLogs(level="WARNING") as warn_log:
            body = f"Test message ...[zulip.txt](http://{hamlet.realm.host}/user_uploads/{hamlet.realm_id}/64/fake_path_id.txt)"
            message_id = self.send_stream_message(
                self.example_user("hamlet"), "Denmark", body, "test"
            )
        self.assertFalse(
            Attachment.objects.filter(path_id=f"{hamlet.realm_id}/64/fake_path_id.txt").exists()
        )

        self.assertEqual(
            warn_log.output,
            [
                f"WARNING:root:User {hamlet.id} tried to share upload {hamlet.realm_id}/64/fake_path_id.txt in message {message_id}, but lacks permission"
            ],
        )

    def test_multiple_claim_attachments(self) -> None:
        """
        This test tries to claim the same attachment twice. The messages field in
        the Attachment model should have both the messages in its entry.
        """
        self.login("hamlet")
        d1 = StringIO("zulip!")
        d1.name = "dummy_1.txt"
        result = self.client_post("/json/user_uploads", {"file": d1})
        response_dict = self.assert_json_success(result)
        d1_path_id = re.sub("/user_uploads/", "", response_dict["uri"])

        self.subscribe(self.example_user("hamlet"), "Denmark")
        host = self.example_user("hamlet").realm.host
        body = f"First message ...[zulip.txt](http://{host}/user_uploads/" + d1_path_id + ")"
        self.send_stream_message(self.example_user("hamlet"), "Denmark", body, "test")
        body = f"Second message ...[zulip.txt](http://{host}/user_uploads/" + d1_path_id + ")"
        self.send_stream_message(self.example_user("hamlet"), "Denmark", body, "test")

        self.assertEqual(Attachment.objects.get(path_id=d1_path_id).messages.count(), 2)

    def test_multiple_claim_attachments_different_owners(self) -> None:
        """This test tries to claim the same attachment more than once, first
        with a private stream and then with different recipients."""
        self.login("hamlet")
        d1 = StringIO("zulip!")
        d1.name = "dummy_1.txt"
        result = self.client_post("/json/user_uploads", {"file": d1})
        response_dict = self.assert_json_success(result)
        d1_path_id = re.sub("/user_uploads/", "", response_dict["uri"])
        host = self.example_user("hamlet").realm.host

        self.make_stream("private_stream", invite_only=True)
        self.subscribe(self.example_user("hamlet"), "private_stream")

        # First, send the message to the new private stream.
        body = f"First message ...[zulip.txt](http://{host}/user_uploads/" + d1_path_id + ")"
        self.send_stream_message(self.example_user("hamlet"), "private_stream", body, "test")
        self.assertFalse(Attachment.objects.get(path_id=d1_path_id).is_realm_public)
        self.assertEqual(Attachment.objects.get(path_id=d1_path_id).messages.count(), 1)

        # Then, try having a user who didn't receive the message try to publish it, and fail
        body = f"Illegal message ...[zulip.txt](http://{host}/user_uploads/" + d1_path_id + ")"
        cordelia = self.example_user("cordelia")
        with self.assertLogs(level="WARNING") as warn_log:
            self.send_stream_message(cordelia, "Verona", body, "test")
        self.assertTrue(
            f"WARNING:root:User {cordelia.id} tried to share upload" in warn_log.output[0]
            and "but lacks permission" in warn_log.output[0]
        )
        self.assertEqual(Attachment.objects.get(path_id=d1_path_id).messages.count(), 1)
        self.assertFalse(Attachment.objects.get(path_id=d1_path_id).is_realm_public)
        self.assertFalse(Attachment.objects.get(path_id=d1_path_id).is_web_public)

        # Then, have it in a direct message to another user, giving that other user access.
        body = f"Second message ...[zulip.txt](http://{host}/user_uploads/" + d1_path_id + ")"
        self.send_personal_message(self.example_user("hamlet"), self.example_user("othello"), body)
        self.assertEqual(Attachment.objects.get(path_id=d1_path_id).messages.count(), 2)
        self.assertFalse(Attachment.objects.get(path_id=d1_path_id).is_realm_public)
        self.assertFalse(Attachment.objects.get(path_id=d1_path_id).is_web_public)

        # Then, have that new recipient user publish it.
        body = f"Third message ...[zulip.txt](http://{host}/user_uploads/" + d1_path_id + ")"
        self.send_stream_message(self.example_user("othello"), "Verona", body, "test")
        self.assertEqual(Attachment.objects.get(path_id=d1_path_id).messages.count(), 3)
        self.assertTrue(Attachment.objects.get(path_id=d1_path_id).is_realm_public)
        self.assertFalse(Attachment.objects.get(path_id=d1_path_id).is_web_public)

        # Finally send to Rome, the web-public stream, and confirm it's now web-public
        body = f"Fourth message ...[zulip.txt](http://{host}/user_uploads/" + d1_path_id + ")"
        self.subscribe(self.example_user("othello"), "Rome")
        self.send_stream_message(self.example_user("othello"), "Rome", body, "test")
        self.assertEqual(Attachment.objects.get(path_id=d1_path_id).messages.count(), 4)
        self.assertTrue(Attachment.objects.get(path_id=d1_path_id).is_realm_public)
        self.assertTrue(Attachment.objects.get(path_id=d1_path_id).is_web_public)

    def test_check_attachment_reference_update(self) -> None:
        f1 = StringIO("file1")
        f1.name = "file1.txt"
        f2 = StringIO("file2")
        f2.name = "file2.txt"
        f3 = StringIO("file3")
        f3.name = "file3.txt"
        hamlet = self.example_user("hamlet")
        host = hamlet.realm.host

        self.login_user(hamlet)
        result = self.client_post("/json/user_uploads", {"file": f1})
        response_dict = self.assert_json_success(result)
        f1_path_id = re.sub("/user_uploads/", "", response_dict["uri"])

        result = self.client_post("/json/user_uploads", {"file": f2})
        response_dict = self.assert_json_success(result)
        f2_path_id = re.sub("/user_uploads/", "", response_dict["uri"])

        self.subscribe(hamlet, "test")
        body = (
            f"[f1.txt](http://{host}/user_uploads/" + f1_path_id + ") "
            f"[f2.txt](http://{host}/user_uploads/" + f2_path_id + ")"
        )
        msg_id = self.send_stream_message(hamlet, "test", body, "test")

        result = self.client_post("/json/user_uploads", {"file": f3})
        response_dict = self.assert_json_success(result)
        f3_path_id = re.sub("/user_uploads/", "", response_dict["uri"])

        new_body = (
            f"[f3.txt](http://{host}/user_uploads/" + f3_path_id + ") "
            f"[f2.txt](http://{host}/user_uploads/" + f2_path_id + ")"
        )
        result = self.client_patch(
            "/json/messages/" + str(msg_id),
            {
                "content": new_body,
            },
        )
        self.assert_json_success(result)

        message = Message.objects.get(id=msg_id)
        f1_attachment = Attachment.objects.get(path_id=f1_path_id)
        f2_attachment = Attachment.objects.get(path_id=f2_path_id)
        f3_attachment = Attachment.objects.get(path_id=f3_path_id)

        self.assertTrue(message not in f1_attachment.messages.all())
        self.assertTrue(message in f2_attachment.messages.all())
        self.assertTrue(message in f3_attachment.messages.all())

        # Delete all the attachments from the message
        new_body = "(deleted)"
        result = self.client_patch(
            "/json/messages/" + str(msg_id),
            {
                "content": new_body,
            },
        )
        self.assert_json_success(result)

        message = Message.objects.get(id=msg_id)
        f1_attachment = Attachment.objects.get(path_id=f1_path_id)
        f2_attachment = Attachment.objects.get(path_id=f2_path_id)
        f3_attachment = Attachment.objects.get(path_id=f3_path_id)
        self.assertTrue(message not in f1_attachment.messages.all())
        self.assertTrue(message not in f2_attachment.messages.all())
        self.assertTrue(message not in f3_attachment.messages.all())

    def test_file_name(self) -> None:
        """
        Unicode filenames should be processed correctly.
        """
        self.login("hamlet")
        for expected in ["Здравейте.txt", "test"]:
            fp = StringIO("bah!")
            fp.name = urllib.parse.quote(expected)

            result = self.client_post("/json/user_uploads", {"f1": fp})
            response_dict = self.assert_json_success(result)
            assert sanitize_name(expected) in response_dict["uri"]

    def test_sanitize_file_name(self) -> None:
        self.login("hamlet")
        for uploaded_filename, expected in [
            ("../foo", "foo"),
            (".. ", "uploaded-file"),
            ("/", "f1"),
            ("./", "f1"),
            ("././", "f1"),
            (".!", "uploaded-file"),
            ("**", "uploaded-file"),
        ]:
            fp = StringIO("bah!")
            fp.name = urllib.parse.quote(uploaded_filename)

            result = self.client_post("/json/user_uploads", {"f1": fp})
            response_dict = self.assert_json_success(result)
            self.assertNotIn(response_dict["uri"], uploaded_filename)
            self.assertTrue(response_dict["uri"].endswith("/" + expected))

    def test_realm_quota(self) -> None:
        """
        Realm quota for uploading should not be exceeded.
        """
        self.login("hamlet")

        d1 = StringIO("zulip!")
        d1.name = "dummy_1.txt"
        result = self.client_post("/json/user_uploads", {"file": d1})
        response_dict = self.assert_json_success(result)
        d1_path_id = re.sub("/user_uploads/", "", response_dict["uri"])
        d1_attachment = Attachment.objects.get(path_id=d1_path_id)

        realm = get_realm("zulip")
        realm.upload_quota_gb = 1
        realm.save(update_fields=["upload_quota_gb"])

        # The size of StringIO("zulip!") is 6 bytes. Setting the size of
        # d1_attachment to realm.upload_quota_bytes() - 11 should allow
        # us to upload only one more attachment.
        quota = realm.upload_quota_bytes()
        assert quota is not None
        d1_attachment.size = quota - 11
        d1_attachment.save(update_fields=["size"])

        d2 = StringIO("zulip!")
        d2.name = "dummy_2.txt"
        result = self.client_post("/json/user_uploads", {"file": d2})
        self.assert_json_success(result)

        d3 = StringIO("zulip!")
        d3.name = "dummy_3.txt"
        result = self.client_post("/json/user_uploads", {"file": d3})
        self.assert_json_error(result, "Upload would exceed your organization's upload quota.")

        realm.upload_quota_gb = None
        realm.save(update_fields=["upload_quota_gb"])
        result = self.client_post("/json/user_uploads", {"file": d3})
        self.assert_json_success(result)

    def test_cross_realm_file_access(self) -> None:
        def create_user(email: str, realm_id: str) -> UserProfile:
            password = initial_password(email)
            if password is not None:
                self.register(email, password, subdomain=realm_id)
                # self.register has the side-effect of ending up with a logged in session
                # for the new user. We don't want that in these tests.
                self.logout()
            return get_user_by_delivery_email(email, get_realm(realm_id))

        test_subdomain = "uploadtest.example.com"
        user1_email = "user1@uploadtest.example.com"
        user2_email = "test-og-bot@zulip.com"
        user3_email = "other-user@uploadtest.example.com"

        r1 = do_create_realm(string_id=test_subdomain, name=test_subdomain)
        do_set_realm_property(r1, "invite_required", False, acting_user=None)
        RealmDomain.objects.create(realm=r1, domain=test_subdomain)

        user_1 = create_user(user1_email, test_subdomain)
        user_2 = create_user(user2_email, "zulip")
        user_3 = create_user(user3_email, test_subdomain)
        host = user_3.realm.host

        # Send a message from @zulip.com -> @uploadtest.example.com
        self.login_user(user_2)
        fp = StringIO("zulip!")
        fp.name = "zulip.txt"
        result = self.client_post("/json/user_uploads", {"file": fp})
        url = self.assert_json_success(result)["uri"]
        fp_path_id = re.sub("/user_uploads/", "", url)
        body = f"First message ...[zulip.txt](http://{host}/user_uploads/" + fp_path_id + ")"
        with self.settings(CROSS_REALM_BOT_EMAILS={user_2.email, user_3.email}):
            internal_send_private_message(
                sender=get_system_bot(user_2.email, user_2.realm_id),
                recipient_user=user_1,
                content=body,
            )

        self.login_user(user_1)
        response = self.client_get(url, subdomain=test_subdomain)
        self.assertEqual(response.status_code, 200)
        self.assertEqual(response.getvalue(), b"zulip!")
        self.logout()

        # Confirm other cross-realm users can't read it.
        self.login_user(user_3)
        response = self.client_get(url, subdomain=test_subdomain)
        self.assertEqual(response.status_code, 403)
        self.assert_in_response("You are not authorized to view this file.", response)

        # Verify that cross-realm access to files for spectators is denied.
        self.logout()
        response = self.client_get(url, subdomain=test_subdomain)
        self.assertEqual(response.status_code, 403)

    def test_file_download_authorization_invite_only(self) -> None:
        hamlet = self.example_user("hamlet")
        cordelia = self.example_user("cordelia")
        realm = hamlet.realm
        subscribed_users = [hamlet, cordelia]
        unsubscribed_users = [self.example_user("othello"), self.example_user("prospero")]
        stream_name = "test-subscribe"
        self.make_stream(
            stream_name, realm=realm, invite_only=True, history_public_to_subscribers=False
        )

        for subscribed_user in subscribed_users:
            self.subscribe(subscribed_user, stream_name)

        self.login_user(hamlet)
        fp = StringIO("zulip!")
        fp.name = "zulip.txt"
        result = self.client_post("/json/user_uploads", {"file": fp})
        url = self.assert_json_success(result)["uri"]
        fp_path_id = re.sub("/user_uploads/", "", url)
        body = f"First message ...[zulip.txt](http://{realm.host}/user_uploads/" + fp_path_id + ")"
        self.send_stream_message(hamlet, stream_name, body, "test")
        self.logout()

        # Owner user should be able to view file
        self.login_user(hamlet)
        with self.assert_database_query_count(5):
            response = self.client_get(url)
            self.assertEqual(response.status_code, 200)
            self.assertEqual(response.getvalue(), b"zulip!")
        self.logout()

        # Subscribed user who received the message should be able to view file
        self.login_user(cordelia)
        with self.assert_database_query_count(6):
            response = self.client_get(url)
            self.assertEqual(response.status_code, 200)
            self.assertEqual(response.getvalue(), b"zulip!")
        self.logout()

        def assert_cannot_access_file(user: UserProfile) -> None:
            response = self.api_get(user, url)
            self.assertEqual(response.status_code, 403)
            self.assert_in_response("You are not authorized to view this file.", response)

        late_subscribed_user = self.example_user("aaron")
        self.subscribe(late_subscribed_user, stream_name)
        assert_cannot_access_file(late_subscribed_user)

        # Unsubscribed user should not be able to view file
        for unsubscribed_user in unsubscribed_users:
            assert_cannot_access_file(unsubscribed_user)

    def test_file_download_authorization_invite_only_with_shared_history(self) -> None:
        user = self.example_user("hamlet")
        polonius = self.example_user("polonius")
        subscribed_users = [user, polonius]
        unsubscribed_users = [self.example_user("othello"), self.example_user("prospero")]
        stream_name = "test-subscribe"
        self.make_stream(
            stream_name, realm=user.realm, invite_only=True, history_public_to_subscribers=True
        )

        for subscribed_user in subscribed_users:
            self.subscribe(subscribed_user, stream_name)

        self.login_user(user)
        fp = StringIO("zulip!")
        fp.name = "zulip.txt"
        result = self.client_post("/json/user_uploads", {"file": fp})
        url = self.assert_json_success(result)["uri"]
        fp_path_id = re.sub("/user_uploads/", "", url)
        body = (
            f"First message ...[zulip.txt](http://{user.realm.host}/user_uploads/"
            + fp_path_id
            + ")"
        )
        self.send_stream_message(user, stream_name, body, "test")
        self.logout()

        # Add aaron as a subscribed after the message was sent
        late_subscribed_user = self.example_user("aaron")
        self.subscribe(late_subscribed_user, stream_name)
        subscribed_users.append(late_subscribed_user)

        # Owner user should be able to view file
        self.login_user(user)
        with self.assert_database_query_count(5):
            response = self.client_get(url)
            self.assertEqual(response.status_code, 200)
            self.assertEqual(response.getvalue(), b"zulip!")
        self.logout()

        # Originally subscribed user should be able to view file
        self.login_user(polonius)
        with self.assert_database_query_count(6):
            response = self.client_get(url)
            self.assertEqual(response.status_code, 200)
            self.assertEqual(response.getvalue(), b"zulip!")
        self.logout()

        # Subscribed user who did not receive the message should also be able to view file
        self.login_user(late_subscribed_user)
        with self.assert_database_query_count(9):
            response = self.client_get(url)
            self.assertEqual(response.status_code, 200)
            self.assertEqual(response.getvalue(), b"zulip!")
        self.logout()
        # It takes a few extra queries to verify access because of shared history.

        def assert_cannot_access_file(user: UserProfile) -> None:
            self.login_user(user)
            # It takes a few extra queries to verify lack of access with shared history.
            with self.assert_database_query_count(8):
                response = self.client_get(url)
            self.assertEqual(response.status_code, 403)
            self.assert_in_response("You are not authorized to view this file.", response)
            self.logout()

        # Unsubscribed user should not be able to view file
        for unsubscribed_user in unsubscribed_users:
            assert_cannot_access_file(unsubscribed_user)

    def test_multiple_message_attachment_file_download(self) -> None:
        hamlet = self.example_user("hamlet")
        for i in range(0, 5):
            stream_name = f"test-subscribe {i}"
            self.make_stream(
                stream_name,
                realm=hamlet.realm,
                invite_only=True,
                history_public_to_subscribers=True,
            )
            self.subscribe(hamlet, stream_name)

        self.login_user(hamlet)
        fp = StringIO("zulip!")
        fp.name = "zulip.txt"
        result = self.client_post("/json/user_uploads", {"file": fp})
        url = self.assert_json_success(result)["uri"]
        fp_path_id = re.sub("/user_uploads/", "", url)
        for i in range(20):
            body = (
                f"First message ...[zulip.txt](http://{hamlet.realm.host}/user_uploads/"
                + fp_path_id
                + ")"
            )
            self.send_stream_message(
                self.example_user("hamlet"), f"test-subscribe {i % 5}", body, "test"
            )
        self.logout()

        user = self.example_user("aaron")
        self.login_user(user)
        with self.assert_database_query_count(8):
            response = self.client_get(url)
            self.assertEqual(response.status_code, 403)
            self.assert_in_response("You are not authorized to view this file.", response)

        self.subscribe(user, "test-subscribe 1")
        self.subscribe(user, "test-subscribe 2")

        # If we were accidentally one query per message, this would be 20+
        with self.assert_database_query_count(9):
            response = self.client_get(url)
            self.assertEqual(response.status_code, 200)
            self.assertEqual(response.getvalue(), b"zulip!")

        with self.assert_database_query_count(6):
            self.assertTrue(validate_attachment_request(user, fp_path_id))

        self.logout()

    def test_file_download_authorization_public(self) -> None:
        subscribed_users = [self.example_user("hamlet"), self.example_user("iago")]
        unsubscribed_users = [self.example_user("othello"), self.example_user("prospero")]
        realm = get_realm("zulip")
        for subscribed_user in subscribed_users:
            self.subscribe(subscribed_user, "test-subscribe")

        self.login("hamlet")
        fp = StringIO("zulip!")
        fp.name = "zulip.txt"
        result = self.client_post("/json/user_uploads", {"file": fp})
        url = self.assert_json_success(result)["uri"]
        fp_path_id = re.sub("/user_uploads/", "", url)
        body = f"First message ...[zulip.txt](http://{realm.host}/user_uploads/" + fp_path_id + ")"
        self.send_stream_message(self.example_user("hamlet"), "test-subscribe", body, "test")
        self.logout()

        # Now all users should be able to access the files
        for user in subscribed_users + unsubscribed_users:
            self.login_user(user)
            response = self.client_get(url)
            self.assertEqual(response.getvalue(), b"zulip!")
            self.logout()

    def test_serve_local(self) -> None:
        def check_xsend_links(
            name: str,
            name_str_for_test: str,
            content_disposition: str = "",
            download: bool = False,
        ) -> None:
            self.login("hamlet")
            fp = StringIO("zulip!")
            fp.name = name
            result = self.client_post("/json/user_uploads", {"file": fp})
            url = self.assert_json_success(result)["uri"]
            fp_path_id = re.sub("/user_uploads/", "", url)
            fp_path = os.path.split(fp_path_id)[0]
            if download:
                url = url.replace("/user_uploads/", "/user_uploads/download/")
            with self.settings(DEVELOPMENT=False):
                response = self.client_get(url)
            assert settings.LOCAL_UPLOADS_DIR is not None
            test_run, worker = os.path.split(os.path.dirname(settings.LOCAL_UPLOADS_DIR))
            self.assertEqual(
                response["X-Accel-Redirect"],
                "/internal/local/uploads/" + fp_path + "/" + name_str_for_test,
            )
            if content_disposition != "":
                self.assertIn("attachment;", response["Content-disposition"])
                self.assertIn(content_disposition, response["Content-disposition"])
            else:
                self.assertIn("inline;", response["Content-disposition"])
            self.assertEqual(set(response["Cache-Control"].split(", ")), {"private", "immutable"})

        check_xsend_links("zulip.txt", "zulip.txt", 'filename="zulip.txt"')
        check_xsend_links(
            "áéБД.txt",
            "%C3%A1%C3%A9%D0%91%D0%94.txt",
            "filename*=utf-8''%C3%A1%C3%A9%D0%91%D0%94.txt",
        )
        check_xsend_links("zulip.html", "zulip.html", 'filename="zulip.html"')
        check_xsend_links("zulip.sh", "zulip.sh", 'filename="zulip.sh"')
        check_xsend_links("zulip.jpeg", "zulip.jpeg")
        check_xsend_links(
            "zulip.jpeg", "zulip.jpeg", download=True, content_disposition='filename="zulip.jpeg"'
        )
        check_xsend_links("áéБД.pdf", "%C3%A1%C3%A9%D0%91%D0%94.pdf")
        check_xsend_links("zulip", "zulip", 'filename="zulip"')


class AvatarTest(UploadSerializeMixin, ZulipTestCase):
    def test_get_avatar_field(self) -> None:
        with self.settings(AVATAR_SALT="salt"):
            url = get_avatar_field(
                user_id=17,
                realm_id=5,
                email="foo@example.com",
                avatar_source=UserProfile.AVATAR_FROM_USER,
                avatar_version=2,
                medium=True,
                client_gravatar=False,
            )

        self.assertEqual(
            url,
            "/user_avatars/5/fc2b9f1a81f4508a4df2d95451a2a77e0524ca0e-medium.png?version=2",
        )

        url = get_avatar_field(
            user_id=9999,
            realm_id=9999,
            email="foo@example.com",
            avatar_source=UserProfile.AVATAR_FROM_GRAVATAR,
            avatar_version=2,
            medium=True,
            client_gravatar=False,
        )

        self.assertEqual(
            url,
            "https://secure.gravatar.com/avatar/b48def645758b95537d4424c84d1a9ff?d=identicon&s=500&version=2",
        )

        url = get_avatar_field(
            user_id=9999,
            realm_id=9999,
            email="foo@example.com",
            avatar_source=UserProfile.AVATAR_FROM_GRAVATAR,
            avatar_version=2,
            medium=True,
            client_gravatar=True,
        )

        self.assertEqual(url, None)

    def test_avatar_url(self) -> None:
        """Verifies URL schemes for avatars and realm icons."""
        backend: ZulipUploadBackend = LocalUploadBackend()
        self.assertEqual(backend.get_public_upload_root_url(), "/user_avatars/")
        self.assertEqual(backend.get_avatar_url("hash", False), "/user_avatars/hash.png")
        self.assertEqual(backend.get_avatar_url("hash", True), "/user_avatars/hash-medium.png")
        self.assertEqual(
            backend.get_realm_icon_url(15, 1), "/user_avatars/15/realm/icon.png?version=1"
        )
        self.assertEqual(
            backend.get_realm_logo_url(15, 1, False), "/user_avatars/15/realm/logo.png?version=1"
        )
        self.assertEqual(
            backend.get_realm_logo_url(15, 1, True),
            "/user_avatars/15/realm/night_logo.png?version=1",
        )

        with self.settings(S3_AVATAR_BUCKET="bucket"):
            backend = S3UploadBackend()
            self.assertEqual(
                backend.get_avatar_url("hash", False), "https://bucket.s3.amazonaws.com/hash"
            )
            self.assertEqual(
                backend.get_avatar_url("hash", True),
                "https://bucket.s3.amazonaws.com/hash-medium.png",
            )
            self.assertEqual(
                backend.get_realm_icon_url(15, 1),
                "https://bucket.s3.amazonaws.com/15/realm/icon.png?version=1",
            )
            self.assertEqual(
                backend.get_realm_logo_url(15, 1, False),
                "https://bucket.s3.amazonaws.com/15/realm/logo.png?version=1",
            )
            self.assertEqual(
                backend.get_realm_logo_url(15, 1, True),
                "https://bucket.s3.amazonaws.com/15/realm/night_logo.png?version=1",
            )

    def test_multiple_upload_failure(self) -> None:
        """
        Attempting to upload two files should fail.
        """
        self.login("hamlet")
        with get_test_image_file("img.png") as fp1, get_test_image_file("img.png") as fp2:
            result = self.client_post("/json/users/me/avatar", {"f1": fp1, "f2": fp2})
        self.assert_json_error(result, "You must upload exactly one avatar.")

    def test_no_file_upload_failure(self) -> None:
        """
        Calling this endpoint with no files should fail.
        """
        self.login("hamlet")

        result = self.client_post("/json/users/me/avatar")
        self.assert_json_error(result, "You must upload exactly one avatar.")

    def test_avatar_changes_disabled_failure(self) -> None:
        """
        Attempting to upload avatar on a realm with avatar changes disabled should fail.
        """
        self.login("cordelia")
        do_set_realm_property(
            self.example_user("cordelia").realm,
            "avatar_changes_disabled",
            True,
            acting_user=None,
        )

        with get_test_image_file("img.png") as fp1:
            result = self.client_post("/json/users/me/avatar", {"f1": fp1})
        self.assert_json_error(result, "Avatar changes are disabled in this organization.")

    correct_files = [
        ("img.png", "png_resized.png"),
        ("img.jpg", None),  # jpeg resizing is platform-dependent
        ("img.gif", "gif_resized.png"),
        ("img.tif", "tif_resized.png"),
        ("cmyk.jpg", None),
    ]
    corrupt_files = ["text.txt", "corrupt.png", "corrupt.gif"]

    def test_get_gravatar_avatar(self) -> None:
        self.login("hamlet")
        cordelia = self.example_user("cordelia")
        cordelia.email = cordelia.delivery_email
        cordelia.save()

        cordelia.avatar_source = UserProfile.AVATAR_FROM_GRAVATAR
        cordelia.save()
        with self.settings(ENABLE_GRAVATAR=True):
            response = self.client_get("/avatar/cordelia@zulip.com", {"foo": "bar"})
            redirect_url = response["Location"]
            self.assertEqual(redirect_url, str(avatar_url(cordelia)) + "&foo=bar")

        with self.settings(ENABLE_GRAVATAR=False):
            response = self.client_get("/avatar/cordelia@zulip.com", {"foo": "bar"})
            redirect_url = response["Location"]
            self.assertTrue(redirect_url.endswith(str(avatar_url(cordelia)) + "&foo=bar"))

    def test_get_settings_avatar(self) -> None:
        self.login("hamlet")
        cordelia = self.example_user("cordelia")
        cordelia.email = cordelia.delivery_email
        cordelia.save()
        with self.settings(
            ENABLE_GRAVATAR=False, DEFAULT_AVATAR_URI="http://other.server/avatar.svg"
        ):
            response = self.client_get("/avatar/cordelia@zulip.com", {"foo": "bar"})
            redirect_url = response["Location"]
            self.assertEqual(redirect_url, "http://other.server/avatar.svg?version=1&foo=bar")

    def test_get_user_avatar(self) -> None:
        hamlet = self.example_user("hamlet")
        self.login_user(hamlet)
        cordelia = self.example_user("cordelia")
        cordelia.email = cordelia.delivery_email
        cordelia.save()

        internal_realm = get_realm(settings.SYSTEM_BOT_REALM)
        cross_realm_bot = get_system_bot(settings.WELCOME_BOT, internal_realm.id)

        cordelia.avatar_source = UserProfile.AVATAR_FROM_USER
        cordelia.save()
        response = self.client_get("/avatar/cordelia@zulip.com", {"foo": "bar"})
        redirect_url = response["Location"]
        self.assertTrue(redirect_url.endswith(str(avatar_url(cordelia)) + "&foo=bar"))

        response = self.client_get(f"/avatar/{cordelia.id}", {"foo": "bar"})
        redirect_url = response["Location"]
        self.assertTrue(redirect_url.endswith(str(avatar_url(cordelia)) + "&foo=bar"))

        response = self.client_get("/avatar/")
        self.assertEqual(response.status_code, 404)

        self.logout()

        with self.settings(WEB_PUBLIC_STREAMS_ENABLED=False):
            # Test /avatar/<email_or_id> endpoint with HTTP basic auth.
            response = self.api_get(hamlet, "/avatar/cordelia@zulip.com", {"foo": "bar"})
            redirect_url = response["Location"]
            self.assertTrue(redirect_url.endswith(str(avatar_url(cordelia)) + "&foo=bar"))

            response = self.api_get(hamlet, f"/avatar/{cordelia.id}", {"foo": "bar"})
            redirect_url = response["Location"]
            self.assertTrue(redirect_url.endswith(str(avatar_url(cordelia)) + "&foo=bar"))

            # Test cross_realm_bot avatar access using email.
            response = self.api_get(hamlet, "/avatar/welcome-bot@zulip.com", {"foo": "bar"})
            redirect_url = response["Location"]
            self.assertTrue(redirect_url.endswith(str(avatar_url(cross_realm_bot)) + "&foo=bar"))

            # Test cross_realm_bot avatar access using id.
            response = self.api_get(hamlet, f"/avatar/{cross_realm_bot.id}", {"foo": "bar"})
            redirect_url = response["Location"]
            self.assertTrue(redirect_url.endswith(str(avatar_url(cross_realm_bot)) + "&foo=bar"))

            # Without spectators enabled, no unauthenticated access.
            response = self.client_get("/avatar/cordelia@zulip.com", {"foo": "bar"})
            self.assert_json_error(
                response,
                "Not logged in: API authentication or user session required",
                status_code=401,
            )

        # Allow unauthenticated/spectator requests by ID.
        response = self.client_get(f"/avatar/{cordelia.id}", {"foo": "bar"})
        self.assertEqual(302, response.status_code)

        # Disallow unauthenticated/spectator requests by email.
        response = self.client_get("/avatar/cordelia@zulip.com", {"foo": "bar"})
        self.assert_json_error(
            response,
            "Not logged in: API authentication or user session required",
            status_code=401,
        )

    def test_get_user_avatar_medium(self) -> None:
        hamlet = self.example_user("hamlet")
        self.login_user(hamlet)
        cordelia = self.example_user("cordelia")
        cordelia.email = cordelia.delivery_email
        cordelia.save()

        cordelia.avatar_source = UserProfile.AVATAR_FROM_USER
        cordelia.save()
        response = self.client_get("/avatar/cordelia@zulip.com/medium", {"foo": "bar"})
        redirect_url = response["Location"]
        self.assertTrue(redirect_url.endswith(str(avatar_url(cordelia, True)) + "&foo=bar"))

        response = self.client_get(f"/avatar/{cordelia.id}/medium", {"foo": "bar"})
        redirect_url = response["Location"]
        self.assertTrue(redirect_url.endswith(str(avatar_url(cordelia, True)) + "&foo=bar"))

        self.logout()

        with self.settings(WEB_PUBLIC_STREAMS_ENABLED=False):
            # Test /avatar/<email_or_id>/medium endpoint with HTTP basic auth.
            response = self.api_get(hamlet, "/avatar/cordelia@zulip.com/medium", {"foo": "bar"})
            redirect_url = response["Location"]
            self.assertTrue(redirect_url.endswith(str(avatar_url(cordelia, True)) + "&foo=bar"))

            response = self.api_get(hamlet, f"/avatar/{cordelia.id}/medium", {"foo": "bar"})
            redirect_url = response["Location"]
            self.assertTrue(redirect_url.endswith(str(avatar_url(cordelia, True)) + "&foo=bar"))

            # Without spectators enabled, no unauthenticated access.
            response = self.client_get("/avatar/cordelia@zulip.com/medium", {"foo": "bar"})
            self.assert_json_error(
                response,
                "Not logged in: API authentication or user session required",
                status_code=401,
            )

        # Allow unauthenticated/spectator requests by ID.
        response = self.client_get(f"/avatar/{cordelia.id}/medium", {"foo": "bar"})
        self.assertEqual(302, response.status_code)

        # Disallow unauthenticated/spectator requests by email.
        response = self.client_get("/avatar/cordelia@zulip.com/medium", {"foo": "bar"})
        self.assert_json_error(
            response,
            "Not logged in: API authentication or user session required",
            status_code=401,
        )

        # Allow unauthenticated/spectator requests by ID for a reasonable number of requests.
        with ratelimit_rule(86400, 1000, domain="spectator_attachment_access_by_file"):
            response = self.client_get(f"/avatar/{cordelia.id}/medium", {"foo": "bar"})
            self.assertEqual(302, response.status_code)

        # Deny file access since rate limited
        with ratelimit_rule(86400, 0, domain="spectator_attachment_access_by_file"):
            response = self.client_get(f"/avatar/{cordelia.id}/medium", {"foo": "bar"})
            self.assertEqual(429, response.status_code)

    def test_non_valid_user_avatar(self) -> None:
        # It's debatable whether we should generate avatars for non-users,
        # but this test just validates the current code's behavior.
        self.login("hamlet")

        response = self.client_get("/avatar/nonexistent_user@zulip.com", {"foo": "bar"})
        redirect_url = response["Location"]
        actual_url = "https://secure.gravatar.com/avatar/444258b521f152129eb0c162996e572d?d=identicon&version=1&foo=bar"
        self.assertEqual(redirect_url, actual_url)

    def test_valid_avatars(self) -> None:
        """
        A PUT request to /json/users/me/avatar with a valid file should return a URL and actually create an avatar.
        """
        version = 2
        for fname, rfname in self.correct_files:
            with self.subTest(fname=fname):
                self.login("hamlet")
                with get_test_image_file(fname) as fp:
                    result = self.client_post("/json/users/me/avatar", {"file": fp})

                response_dict = self.assert_json_success(result)
                self.assertIn("avatar_url", response_dict)
                base = "/user_avatars/"
                url = self.assert_json_success(result)["avatar_url"]
                self.assertEqual(base, url[: len(base)])

                if rfname is not None:
                    response = self.client_get(url)
                    data = response.getvalue()
                    self.assertEqual(Image.open(io.BytesIO(data)).size, (100, 100))

                # Verify that the medium-size avatar was created
                user_profile = self.example_user("hamlet")
                medium_avatar_disk_path = avatar_disk_path(user_profile, medium=True)
                self.assertTrue(os.path.exists(medium_avatar_disk_path))

                # Verify that ensure_medium_avatar_url does not overwrite this file if it exists
                with mock.patch(
                    "zerver.lib.upload.local.write_local_file"
                ) as mock_write_local_file:
                    zerver.lib.upload.upload_backend.ensure_avatar_image(
                        user_profile, is_medium=True
                    )
                    self.assertFalse(mock_write_local_file.called)

                # Confirm that ensure_medium_avatar_url works to recreate
                # medium size avatars from the original if needed
                os.remove(medium_avatar_disk_path)
                self.assertFalse(os.path.exists(medium_avatar_disk_path))
                zerver.lib.upload.upload_backend.ensure_avatar_image(user_profile, is_medium=True)
                self.assertTrue(os.path.exists(medium_avatar_disk_path))

                # Verify whether the avatar_version gets incremented with every new upload
                self.assertEqual(user_profile.avatar_version, version)
                version += 1

    def test_copy_avatar_image(self) -> None:
        self.login("hamlet")
        with get_test_image_file("img.png") as image_file:
            self.client_post("/json/users/me/avatar", {"file": image_file})

        source_user_profile = self.example_user("hamlet")
        target_user_profile = self.example_user("iago")

        copy_default_settings(source_user_profile, target_user_profile)

        source_path_id = avatar_disk_path(source_user_profile)
        target_path_id = avatar_disk_path(target_user_profile)
        self.assertNotEqual(source_path_id, target_path_id)
        with open(source_path_id, "rb") as source, open(target_path_id, "rb") as target:
            self.assertEqual(source.read(), target.read())

        source_original_path_id = avatar_disk_path(source_user_profile, original=True)
        target_original_path_id = avatar_disk_path(target_user_profile, original=True)
        with open(source_original_path_id, "rb") as source, open(
            target_original_path_id, "rb"
        ) as target:
            self.assertEqual(source.read(), target.read())

        source_medium_path_id = avatar_disk_path(source_user_profile, medium=True)
        target_medium_path_id = avatar_disk_path(target_user_profile, medium=True)
        with open(source_medium_path_id, "rb") as source, open(
            target_medium_path_id, "rb"
        ) as target:
            self.assertEqual(source.read(), target.read())

    def test_delete_avatar_image(self) -> None:
        self.login("hamlet")
        with get_test_image_file("img.png") as image_file:
            self.client_post("/json/users/me/avatar", {"file": image_file})

        user = self.example_user("hamlet")

        avatar_path_id = avatar_disk_path(user)
        avatar_original_path_id = avatar_disk_path(user, original=True)
        avatar_medium_path_id = avatar_disk_path(user, medium=True)

        self.assertEqual(user.avatar_source, UserProfile.AVATAR_FROM_USER)
        self.assertTrue(os.path.isfile(avatar_path_id))
        self.assertTrue(os.path.isfile(avatar_original_path_id))
        self.assertTrue(os.path.isfile(avatar_medium_path_id))

        do_delete_avatar_image(user, acting_user=user)

        self.assertEqual(user.avatar_source, UserProfile.AVATAR_FROM_GRAVATAR)
        self.assertFalse(os.path.isfile(avatar_path_id))
        self.assertFalse(os.path.isfile(avatar_original_path_id))
        self.assertFalse(os.path.isfile(avatar_medium_path_id))

    def test_invalid_avatars(self) -> None:
        """
        A PUT request to /json/users/me/avatar with an invalid file should fail.
        """
        for fname in self.corrupt_files:
            with self.subTest(fname=fname):
                self.login("hamlet")
                with get_test_image_file(fname) as fp:
                    result = self.client_post("/json/users/me/avatar", {"file": fp})

                self.assert_json_error(
                    result, "Could not decode image; did you upload an image file?"
                )
                user_profile = self.example_user("hamlet")
                self.assertEqual(user_profile.avatar_version, 1)

    def test_delete_avatar(self) -> None:
        """
        A DELETE request to /json/users/me/avatar should delete the profile picture and return gravatar URL
        """
        self.login("cordelia")
        cordelia = self.example_user("cordelia")
        cordelia.avatar_source = UserProfile.AVATAR_FROM_USER
        cordelia.save()

        do_set_realm_property(cordelia.realm, "avatar_changes_disabled", True, acting_user=None)
        result = self.client_delete("/json/users/me/avatar")
        self.assert_json_error(result, "Avatar changes are disabled in this organization.", 400)

        do_set_realm_property(cordelia.realm, "avatar_changes_disabled", False, acting_user=None)
        result = self.client_delete("/json/users/me/avatar")
        user_profile = self.example_user("cordelia")

        response_dict = self.assert_json_success(result)
        self.assertIn("avatar_url", response_dict)
        self.assertEqual(response_dict["avatar_url"], avatar_url(user_profile))

        self.assertEqual(user_profile.avatar_source, UserProfile.AVATAR_FROM_GRAVATAR)
        self.assertEqual(user_profile.avatar_version, 2)

    def test_avatar_upload_file_size_error(self) -> None:
        self.login("hamlet")
        with get_test_image_file(self.correct_files[0][0]) as fp:
            with self.settings(MAX_AVATAR_FILE_SIZE_MIB=0):
                result = self.client_post("/json/users/me/avatar", {"file": fp})
        self.assert_json_error(result, "Uploaded file is larger than the allowed limit of 0 MiB")


class EmojiTest(UploadSerializeMixin, ZulipTestCase):
    # While testing GIF resizing, we can't test if the final GIF has the same
    # number of frames as the original one because PIL drops duplicate frames
    # with a corresponding increase in the duration of the previous frame.
    def test_resize_emoji(self) -> None:
        # Test unequal width and height of animated GIF image
        animated_unequal_img_data = read_test_image_file("animated_unequal_img.gif")
        resized_img_data, is_animated, still_img_data = resize_emoji(
            animated_unequal_img_data, size=50
        )
        im = Image.open(io.BytesIO(resized_img_data))
        self.assertEqual((50, 50), im.size)
        self.assertTrue(is_animated)
        assert still_img_data is not None
        still_image = Image.open(io.BytesIO(still_img_data))
        self.assertEqual((50, 50), still_image.size)

        # Test corrupt image exception
        corrupted_img_data = read_test_image_file("corrupt.gif")
        with self.assertRaises(BadImageError):
            resize_emoji(corrupted_img_data)

        for img_format in ("gif", "png"):
            animated_large_img_data = read_test_image_file(f"animated_large_img.{img_format}")

            def test_resize(size: int = 50) -> None:
                resized_img_data, is_animated, still_img_data = resize_emoji(
                    animated_large_img_data, size=50
                )
                im = Image.open(io.BytesIO(resized_img_data))
                self.assertEqual((size, size), im.size)
                self.assertTrue(is_animated)
                assert still_img_data
                still_image = Image.open(io.BytesIO(still_img_data))
                self.assertEqual((50, 50), still_image.size)

            # Test an image larger than max is resized
            with patch("zerver.lib.upload.base.MAX_EMOJI_GIF_SIZE", 128):
                test_resize()

            # Test an image file larger than max is resized
            with patch("zerver.lib.upload.base.MAX_EMOJI_GIF_FILE_SIZE_BYTES", 3 * 1024 * 1024):
                test_resize()

            # Test an image smaller than max and smaller than file size max is not resized
            with patch("zerver.lib.upload.base.MAX_EMOJI_GIF_SIZE", 512):
                test_resize(size=256)

        # Test a non-animated GIF image which does need to be resized
        still_large_img_data = read_test_image_file("still_large_img.gif")
        resized_img_data, is_animated, no_still_data = resize_emoji(still_large_img_data, size=50)
        im = Image.open(io.BytesIO(resized_img_data))
        self.assertEqual((50, 50), im.size)
        self.assertFalse(is_animated)
        assert no_still_data is None

        # Test a non-animated and non-animatable image format which needs to be resized
        still_large_img_data = read_test_image_file("img.jpg")
        resized_img_data, is_animated, no_still_data = resize_emoji(still_large_img_data, size=50)
        im = Image.open(io.BytesIO(resized_img_data))
        self.assertEqual((50, 50), im.size)
        self.assertFalse(is_animated)
        assert no_still_data is None


class RealmIconTest(UploadSerializeMixin, ZulipTestCase):
    def test_multiple_upload_failure(self) -> None:
        """
        Attempting to upload two files should fail.
        """
        # Log in as admin
        self.login("iago")
        with get_test_image_file("img.png") as fp1, get_test_image_file("img.png") as fp2:
            result = self.client_post("/json/realm/icon", {"f1": fp1, "f2": fp2})
        self.assert_json_error(result, "You must upload exactly one icon.")

    def test_no_file_upload_failure(self) -> None:
        """
        Calling this endpoint with no files should fail.
        """
        self.login("iago")

        result = self.client_post("/json/realm/icon")
        self.assert_json_error(result, "You must upload exactly one icon.")

    correct_files = [
        ("img.png", "png_resized.png"),
        ("img.jpg", None),  # jpeg resizing is platform-dependent
        ("img.gif", "gif_resized.png"),
        ("img.tif", "tif_resized.png"),
        ("cmyk.jpg", None),
    ]
    corrupt_files = ["text.txt", "corrupt.png", "corrupt.gif"]

    def test_no_admin_user_upload(self) -> None:
        self.login("hamlet")
        with get_test_image_file(self.correct_files[0][0]) as fp:
            result = self.client_post("/json/realm/icon", {"file": fp})
        self.assert_json_error(result, "Must be an organization administrator")

    def test_get_gravatar_icon(self) -> None:
        self.login("hamlet")
        realm = get_realm("zulip")
        do_change_icon_source(realm, Realm.ICON_FROM_GRAVATAR, acting_user=None)
        with self.settings(ENABLE_GRAVATAR=True):
            response = self.client_get("/json/realm/icon", {"foo": "bar"})
            redirect_url = response["Location"]
            self.assertEqual(redirect_url, realm_icon_url(realm) + "&foo=bar")

        with self.settings(ENABLE_GRAVATAR=False):
            response = self.client_get("/json/realm/icon", {"foo": "bar"})
            redirect_url = response["Location"]
            self.assertTrue(redirect_url.endswith(realm_icon_url(realm) + "&foo=bar"))

    def test_get_settings_realm_icon(self) -> None:
        self.login("hamlet")
        with self.settings(
            ENABLE_GRAVATAR=False, DEFAULT_AVATAR_URI="http://other.server/icon.svg"
        ):
            response = self.client_get("/json/realm/icon", {"foo": "bar"})
            redirect_url = response["Location"]
            self.assertEqual(redirect_url, "http://other.server/icon.svg?foo=bar")

    def test_get_uploaded_realm_icon(self) -> None:
        self.login("hamlet")

        realm = get_realm("zulip")
        do_change_icon_source(realm, Realm.ICON_UPLOADED, acting_user=None)
        response = self.client_get("/json/realm/icon", {"foo": "bar"})
        redirect_url = response["Location"]
        self.assertTrue(redirect_url.endswith(realm_icon_url(realm) + "&foo=bar"))

    def test_valid_icons(self) -> None:
        """
        A PUT request to /json/realm/icon with a valid file should return a URL
        and actually create an realm icon.
        """
        for fname, rfname in self.correct_files:
            with self.subTest(fname=fname):
                self.login("iago")
                with get_test_image_file(fname) as fp:
                    result = self.client_post("/json/realm/icon", {"file": fp})
                realm = get_realm("zulip")
                response_dict = self.assert_json_success(result)
                self.assertIn("icon_url", response_dict)
                base = f"/user_avatars/{realm.id}/realm/icon.png"
                url = response_dict["icon_url"]
                self.assertEqual(base, url[: len(base)])

                if rfname is not None:
                    response = self.client_get(url)
                    data = response.getvalue()
                    self.assertEqual(Image.open(io.BytesIO(data)).size, (100, 100))

    def test_invalid_icons(self) -> None:
        """
        A PUT request to /json/realm/icon with an invalid file should fail.
        """
        for fname in self.corrupt_files:
            with self.subTest(fname=fname):
                self.login("iago")
                with get_test_image_file(fname) as fp:
                    result = self.client_post("/json/realm/icon", {"file": fp})

                self.assert_json_error(
                    result, "Could not decode image; did you upload an image file?"
                )

    def test_delete_icon(self) -> None:
        """
        A DELETE request to /json/realm/icon should delete the realm icon and return gravatar URL
        """
        self.login("iago")
        realm = get_realm("zulip")
        do_change_icon_source(realm, Realm.ICON_UPLOADED, acting_user=None)

        result = self.client_delete("/json/realm/icon")

        response_dict = self.assert_json_success(result)
        self.assertIn("icon_url", response_dict)
        realm = get_realm("zulip")
        self.assertEqual(response_dict["icon_url"], realm_icon_url(realm))
        self.assertEqual(realm.icon_source, Realm.ICON_FROM_GRAVATAR)

    def test_realm_icon_version(self) -> None:
        self.login("iago")
        realm = get_realm("zulip")
        icon_version = realm.icon_version
        self.assertEqual(icon_version, 1)
        with get_test_image_file(self.correct_files[0][0]) as fp:
            self.client_post("/json/realm/icon", {"file": fp})
        realm = get_realm("zulip")
        self.assertEqual(realm.icon_version, icon_version + 1)

    def test_realm_icon_upload_file_size_error(self) -> None:
        self.login("iago")
        with get_test_image_file(self.correct_files[0][0]) as fp:
            with self.settings(MAX_ICON_FILE_SIZE_MIB=0):
                result = self.client_post("/json/realm/icon", {"file": fp})
        self.assert_json_error(result, "Uploaded file is larger than the allowed limit of 0 MiB")


class RealmLogoTest(UploadSerializeMixin, ZulipTestCase):
    night = False

    def test_multiple_upload_failure(self) -> None:
        """
        Attempting to upload two files should fail.
        """
        # Log in as admin
        self.login("iago")
        with get_test_image_file("img.png") as fp1, get_test_image_file("img.png") as fp2:
            result = self.client_post(
                "/json/realm/logo",
                {"f1": fp1, "f2": fp2, "night": orjson.dumps(self.night).decode()},
            )
        self.assert_json_error(result, "You must upload exactly one logo.")

    def test_no_file_upload_failure(self) -> None:
        """
        Calling this endpoint with no files should fail.
        """
        self.login("iago")

        result = self.client_post("/json/realm/logo", {"night": orjson.dumps(self.night).decode()})
        self.assert_json_error(result, "You must upload exactly one logo.")

    correct_files = [
        ("img.png", "png_resized.png"),
        ("img.jpg", None),  # jpeg resizing is platform-dependent
        ("img.gif", "gif_resized.png"),
        ("img.tif", "tif_resized.png"),
        ("cmyk.jpg", None),
    ]
    corrupt_files = ["text.txt", "corrupt.png", "corrupt.gif"]

    def test_no_admin_user_upload(self) -> None:
        self.login("hamlet")
        with get_test_image_file(self.correct_files[0][0]) as fp:
            result = self.client_post(
                "/json/realm/logo", {"file": fp, "night": orjson.dumps(self.night).decode()}
            )
        self.assert_json_error(result, "Must be an organization administrator")

    def test_upload_limited_plan_type(self) -> None:
        user_profile = self.example_user("iago")
        do_change_realm_plan_type(user_profile.realm, Realm.PLAN_TYPE_LIMITED, acting_user=None)
        self.login_user(user_profile)
        with get_test_image_file(self.correct_files[0][0]) as fp:
            result = self.client_post(
                "/json/realm/logo", {"file": fp, "night": orjson.dumps(self.night).decode()}
            )
        self.assert_json_error(result, "Available on Zulip Cloud Standard. Upgrade to access.")

    def test_get_default_logo(self) -> None:
        user_profile = self.example_user("hamlet")
        self.login_user(user_profile)
        realm = user_profile.realm
        do_change_logo_source(realm, Realm.LOGO_DEFAULT, self.night, acting_user=user_profile)
        response = self.client_get("/json/realm/logo", {"night": orjson.dumps(self.night).decode()})
        redirect_url = response["Location"]
        is_night_str = str(self.night).lower()
        self.assertEqual(
            redirect_url,
            f"http://testserver/static/images/logo/zulip-org-logo.svg?version=0&night={is_night_str}",
        )

    def test_get_settings_logo(self) -> None:
        self.login("hamlet")
        with self.settings(DEFAULT_LOGO_URI="http://other.server/logo.svg"):
            response = self.client_get(
                "/json/realm/logo", {"night": orjson.dumps(self.night).decode()}
            )
            redirect_url = response["Location"]
            self.assertEqual(
                redirect_url,
                f"http://other.server/logo.svg?night={str(self.night).lower()}",
            )

    def test_get_realm_logo(self) -> None:
        user_profile = self.example_user("hamlet")
        self.login_user(user_profile)
        realm = user_profile.realm
        do_change_logo_source(realm, Realm.LOGO_UPLOADED, self.night, acting_user=user_profile)
        response = self.client_get("/json/realm/logo", {"night": orjson.dumps(self.night).decode()})
        redirect_url = response["Location"]
        self.assertTrue(
            redirect_url.endswith(
                get_realm_logo_url(realm, self.night) + f"&night={str(self.night).lower()}"
            )
        )

        is_night_str = str(self.night).lower()

        if self.night:
            file_name = "night_logo.png"
        else:
            file_name = "logo.png"
        self.assertEqual(
            redirect_url,
            f"/user_avatars/{realm.id}/realm/{file_name}?version=2&night={is_night_str}",
        )

        do_change_realm_plan_type(realm, Realm.PLAN_TYPE_LIMITED, acting_user=user_profile)
        if self.night:
            self.assertEqual(realm.night_logo_source, Realm.LOGO_UPLOADED)
        else:
            self.assertEqual(realm.logo_source, Realm.LOGO_UPLOADED)
        response = self.client_get("/json/realm/logo", {"night": orjson.dumps(self.night).decode()})
        redirect_url = response["Location"]
        self.assertEqual(
            redirect_url,
            f"http://testserver/static/images/logo/zulip-org-logo.svg?version=0&night={is_night_str}",
        )

    def test_valid_logos(self) -> None:
        """
        A PUT request to /json/realm/logo with a valid file should return a URL
        and actually create an realm logo.
        """
        for fname, rfname in self.correct_files:
            with self.subTest(fname=fname):
                self.login("iago")
                with get_test_image_file(fname) as fp:
                    result = self.client_post(
                        "/json/realm/logo", {"file": fp, "night": orjson.dumps(self.night).decode()}
                    )
                realm = get_realm("zulip")
                self.assert_json_success(result)
                logo_url = get_realm_logo_url(realm, self.night)

                if rfname is not None:
                    response = self.client_get(logo_url)
                    data = response.getvalue()
                    # size should be 100 x 100 because thumbnail keeps aspect ratio
                    # while trying to fit in a 800 x 100 box without losing part of the image
                    self.assertEqual(Image.open(io.BytesIO(data)).size, (100, 100))

    def test_invalid_logo_upload(self) -> None:
        """
        A PUT request to /json/realm/logo with an invalid file should fail.
        """
        for fname in self.corrupt_files:
            with self.subTest(fname=fname):
                self.login("iago")
                with get_test_image_file(fname) as fp:
                    result = self.client_post(
                        "/json/realm/logo", {"file": fp, "night": orjson.dumps(self.night).decode()}
                    )

                self.assert_json_error(
                    result, "Could not decode image; did you upload an image file?"
                )

    def test_delete_logo(self) -> None:
        """
        A DELETE request to /json/realm/logo should delete the realm logo and return gravatar URL
        """
        user_profile = self.example_user("iago")
        self.login_user(user_profile)
        realm = user_profile.realm
        do_change_logo_source(realm, Realm.LOGO_UPLOADED, self.night, acting_user=user_profile)
        result = self.client_delete(
            "/json/realm/logo", {"night": orjson.dumps(self.night).decode()}
        )
        self.assert_json_success(result)
        realm = get_realm("zulip")
        if self.night:
            self.assertEqual(realm.night_logo_source, Realm.LOGO_DEFAULT)
        else:
            self.assertEqual(realm.logo_source, Realm.LOGO_DEFAULT)

    def test_logo_version(self) -> None:
        self.login("iago")
        realm = get_realm("zulip")
        if self.night:
            version = realm.night_logo_version
        else:
            version = realm.logo_version
        self.assertEqual(version, 1)
        with get_test_image_file(self.correct_files[0][0]) as fp:
            self.client_post(
                "/json/realm/logo", {"file": fp, "night": orjson.dumps(self.night).decode()}
            )
        realm = get_realm("zulip")
        if self.night:
            self.assertEqual(realm.night_logo_version, version + 1)
        else:
            self.assertEqual(realm.logo_version, version + 1)

    def test_logo_upload_file_size_error(self) -> None:
        self.login("iago")
        with get_test_image_file(self.correct_files[0][0]) as fp:
            with self.settings(MAX_LOGO_FILE_SIZE_MIB=0):
                result = self.client_post(
                    "/json/realm/logo", {"file": fp, "night": orjson.dumps(self.night).decode()}
                )
        self.assert_json_error(result, "Uploaded file is larger than the allowed limit of 0 MiB")


class RealmNightLogoTest(RealmLogoTest):
    # Run the same tests as for RealmLogoTest, just with dark theme enabled
    night = True


class SanitizeNameTests(ZulipTestCase):
    def test_file_name(self) -> None:
        self.assertEqual(sanitize_name("test.txt"), "test.txt")
        self.assertEqual(sanitize_name(".hidden"), ".hidden")
        self.assertEqual(sanitize_name(".hidden.txt"), ".hidden.txt")
        self.assertEqual(sanitize_name("tarball.tar.gz"), "tarball.tar.gz")
        self.assertEqual(sanitize_name(".hidden_tarball.tar.gz"), ".hidden_tarball.tar.gz")
        self.assertEqual(sanitize_name("Testing{}*&*#().ta&&%$##&&r.gz"), "Testing.tar.gz")
        self.assertEqual(sanitize_name("*testingfile?*.txt"), "testingfile.txt")
        self.assertEqual(sanitize_name("snowman☃.txt"), "snowman.txt")
        self.assertEqual(sanitize_name("테스트.txt"), "테스트.txt")
        self.assertEqual(
            sanitize_name('~/."\\`\\?*"u0`000ssh/test.t**{}ar.gz'), ".u0000sshtest.tar.gz"
        )


class UploadSpaceTests(UploadSerializeMixin, ZulipTestCase):
    def setUp(self) -> None:
        super().setUp()
        self.realm = get_realm("zulip")
        self.user_profile = self.example_user("hamlet")

    def test_currently_used_upload_space(self) -> None:
        self.assertEqual(None, cache_get(get_realm_used_upload_space_cache_key(self.realm.id)))
        self.assertEqual(0, self.realm.currently_used_upload_space_bytes())
        self.assertEqual(0, cache_get(get_realm_used_upload_space_cache_key(self.realm.id))[0])

        data = b"zulip!"
        upload_message_attachment("dummy.txt", len(data), "text/plain", data, self.user_profile)
        # notify_attachment_update function calls currently_used_upload_space_bytes which
        # updates the cache.
        self.assert_length(data, cache_get(get_realm_used_upload_space_cache_key(self.realm.id))[0])
        self.assert_length(data, self.realm.currently_used_upload_space_bytes())

        data2 = b"more-data!"
        upload_message_attachment("dummy2.txt", len(data2), "text/plain", data2, self.user_profile)
        self.assertEqual(
            len(data) + len(data2),
            cache_get(get_realm_used_upload_space_cache_key(self.realm.id))[0],
        )
        self.assertEqual(len(data) + len(data2), self.realm.currently_used_upload_space_bytes())

        attachment = Attachment.objects.get(file_name="dummy.txt")
        attachment.file_name = "dummy1.txt"
        attachment.save(update_fields=["file_name"])
        self.assertEqual(
            len(data) + len(data2),
            cache_get(get_realm_used_upload_space_cache_key(self.realm.id))[0],
        )
        self.assertEqual(len(data) + len(data2), self.realm.currently_used_upload_space_bytes())

        attachment.delete()
        self.assertEqual(None, cache_get(get_realm_used_upload_space_cache_key(self.realm.id)))
        self.assert_length(data2, self.realm.currently_used_upload_space_bytes())


class DecompressionBombTests(ZulipTestCase):
    def setUp(self) -> None:
        super().setUp()
        self.test_urls = [
            "/json/users/me/avatar",
            "/json/realm/logo",
            "/json/realm/icon",
            "/json/realm/emoji/bomb_emoji",
        ]

    def test_decompression_bomb(self) -> None:
        self.login("iago")
        with get_test_image_file("bomb.png") as fp:
            for url in self.test_urls:
                fp.seek(0, 0)
                if url == "/json/realm/logo":
                    result = self.client_post(
                        url, {"f1": fp, "night": orjson.dumps(False).decode()}
                    )
                else:
                    result = self.client_post(url, {"f1": fp})
                self.assert_json_error(result, "Image size exceeds limit.")