feat: Support IIIF Image's API HEAD requests (DEV-4072)

src/SipiHttpServer.cpp

@@ -1191,6 +1191,7 @@ static void serve_iiif(Connection &conn_obj,
   const std::string &uri,
   std::vector<std::string> params)
 {
+  auto not_head_request = conn_obj.method() != Connection::HEAD;
   //
   // getting the identifier (which in case of a PDF or multipage TIFF my contain a page id (identifier@pagenum)
   //
@@ -1387,7 +1388,7 @@ static void serve_iiif(Connection &conn_obj,
     }
     }
     try {
-      conn_obj.sendFile(infile);
+      if (not_head_request) conn_obj.sendFile(infile);
     } catch (shttps::InputFailure iofail) {
       syslog(LOG_WARNING, "Browser unexpectedly closed connection");
     } catch (Sipi::SipiError &err) {
@@ -1430,7 +1431,7 @@ static void serve_iiif(Connection &conn_obj,
 
       try {
         //!> send the file from cache
-        conn_obj.sendFile(cachefile);
+        if (not_head_request) conn_obj.sendFile(cachefile);
         //!> from now on the cache file can be deleted again
       } catch (shttps::InputFailure err) {
         // -1 was thrown
@@ -1530,15 +1531,15 @@ static void serve_iiif(Connection &conn_obj,
       conn_obj.header("Content-Type", "image/jpeg");// set the header (mimetype)
       conn_obj.setChunkedTransfer();
       Sipi::SipiCompressionParams qp = { { JPEG_QUALITY, std::to_string(server->jpeg_quality()) } };
-      img.write("jpg", "HTTP", &qp);
+      if (not_head_request) img.write("jpg", "HTTP", &qp);
       break;
     }
     case SipiQualityFormat::JP2: {
       conn_obj.status(Connection::OK);
       conn_obj.header("Link", canonical_header);
       conn_obj.header("Content-Type", "image/jp2");// set the header (mimetype)
       conn_obj.setChunkedTransfer();
-      img.write("jpx", "HTTP");
+      if (not_head_request) img.write("jpx", "HTTP");
       break;
     }
     case SipiQualityFormat::TIF: {
@@ -1547,7 +1548,7 @@ static void serve_iiif(Connection &conn_obj,
       conn_obj.header("Content-Type", "image/tiff");// set the header (mimetype)
       // no chunked transfer needed...
 
-      img.write("tif", "HTTP");
+      if (not_head_request) img.write("tif", "HTTP");
       break;
     }
     case SipiQualityFormat::PNG: {
@@ -1556,7 +1557,7 @@ static void serve_iiif(Connection &conn_obj,
       conn_obj.header("Content-Type", "image/png");// set the header (mimetype)
       conn_obj.setChunkedTransfer();
 
-      img.write("png", "HTTP");
+      if (not_head_request) img.write("png", "HTTP");
       break;
     }
     default: {
@@ -1701,6 +1702,7 @@ void SipiHttpServer::run()
 
   add_route(Connection::GET, "/favicon.ico", favicon_handler);
   add_route(Connection::GET, "/", iiif_handler);
+  add_route(Connection::HEAD, "/", iiif_handler);
 
   user_data(this);
 

test/e2e/conftest.py

@@ -298,7 +298,7 @@ def compare_server_images(self, url_path, expected_file_path, headers=None):
             raise SipiTestError(
                 "Sipi compare: pixels not identical {} {}:\n {}".format(downloaded_file_path, expected_file_path, compare_process.stdout))
 
-    def expect_status_code(self, url_path, status_code, headers=None):
+    def expect_status_code(self, url_path, status_code, headers=None, method='get'):
         """
         Requests a file and expects to get a particular HTTP status code.
 
@@ -308,15 +308,13 @@ def expect_status_code(self, url_path, status_code, headers=None):
         """
 
         sipi_url = self.make_sipi_url(url_path)
-        response = requests.get(sipi_url, headers=headers)
+        response = getattr(requests, method)(sipi_url, headers=headers)
 
         if response.status_code != status_code:
-            raise SipiTestError(
-                "Received status code {} for URL {}, expected {} (wrote {}). Response:\n{}".format(response.status_code,
-                                                                                                   sipi_url,
-                                                                                                   status_code,
-                                                                                                   self.sipi_log_file,
-                                                                                                   response.text))
+            format = "Received status code {} for URL {}, expected {} (wrote {}). Response:\n{}"
+            raise SipiTestError(format.format(response.status_code, sipi_url, status_code, self.sipi_log_file, response.text))
+
+        return response
 
     def get_image_info(self, url_path, headers=None):
         """

test/e2e/test_02_server.py

@@ -18,22 +18,21 @@
 # See the GNU Affero General Public License for more details.
 # You should have received a copy of the GNU Affero General Public
 # License along with Sipi.  If not, see <http://www.gnu.org/licenses/>.
-import filecmp
-import pprint
-import shutil
 
-import pytest
 from pathlib import Path
+import datetime
+import filecmp
 import os
 import os.path
-import time
-import datetime
+import pprint
+import pytest
+import shutil
+import subprocess
 import sys
-
+import time
 
 # Tests basic functionality of the Sipi server.
 
-
 class TestServer:
     component = "The Sipi server"
 
@@ -161,6 +160,15 @@ def test_odd_file(self, manager):
         downloaded_file_path = manager.download_file("/unit/{}/file".format(filename))
         assert filecmp.cmp(manager.data_dir_path("knora/test_odd.odd"), downloaded_file_path)
 
+    def test_head_response_should_be_empty(self, manager):
+        response_json = manager.post_file("/api/upload", manager.data_dir_path("unit/lena512.tif"), "image/tiff")
+
+        http_response = manager.expect_status_code("/unit/{}/full/max/0/default.jpg".format(response_json["filename"]), 200)
+        process = subprocess.run(['file', '-'], input=http_response.content, capture_output=True)
+        assert process.stdout.startswith(b'/dev/stdin: JPEG image data, JFIF standard 1.01, aspect ratio, density 1x1, segment length 16')
+
+        http_response = manager.expect_status_code("/unit/{}/full/max/0/default.jpg".format(response_json["filename"]), 200, method='head')
+        assert http_response.text == ""
 
     def test_mimeconsistency(self, manager):
         """upload any file and check mimetype consistency"""