feat(page): add page param to support pagination without knowing dids (…

…#254)

* feat(page): add page param to support pagination without knowing dids

* fix(page): don't default page value

* fix(page): check if none

* feat(page): order by udpated date when paginating with page

* fix(page): fix order by when page is zero

* feat(pagination): always order by date, add unit test for pagination

indexd/alias/drivers/alchemy.py

@@ -138,7 +138,7 @@ def session(self):
         finally:
             session.close()
 
-    def aliases(self, limit=100, start=None, size=None, hashes=None):
+    def aliases(self, limit=100, start=None, size=None, hashes=None, page=None):
         """
         Returns list of records stored by the backend.
         """

indexd/index/blueprint.py

@@ -57,11 +57,12 @@ def get_index():
     """
     limit = flask.request.args.get("limit")
     start = flask.request.args.get("start")
+    page = flask.request.args.get("page")
 
     ids = flask.request.args.get("ids")
     if ids:
         ids = ids.split(",")
-        if start is not None or limit is not None:
+        if start is not None or limit is not None or page is not None:
             raise UserError("pagination is not supported when ids is provided")
     try:
         limit = 100 if limit is None else int(limit)
@@ -71,6 +72,12 @@ def get_index():
     if limit < 0 or limit > 1024:
         raise UserError("limit must be between 0 and 1024")
 
+    if page is not None:
+        try:
+            page = int(page)
+        except ValueError as err:
+            raise UserError("page must be an integer")
+
     size = flask.request.args.get("size")
     try:
         size = size if size is None else int(size)
@@ -123,6 +130,7 @@ def get_index():
     records = blueprint.index_driver.ids(
         start=start,
         limit=limit,
+        page=page,
         size=size,
         file_name=file_name,
         version=version,
@@ -142,6 +150,7 @@ def get_index():
         "records": records,
         "limit": limit,
         "start": start,
+        "page": page,
         "size": size,
         "file_name": file_name,
         "version": version,

indexd/index/drivers/alchemy.py

@@ -323,6 +323,7 @@ def session(self):
     def ids(
         self,
         limit=100,
+        page=None,
         start=None,
         size=None,
         urls=None,
@@ -432,14 +433,23 @@ def ids(
             if urls_metadata or negate_params:
                 query = query.distinct(IndexRecord.did)
 
-            query = query.order_by(IndexRecord.did)
+            # order by updated date so newly added stuff is
+            # at the end (reduce risk that a new records ends up in a page
+            # earlier on) and allows for some logic to check for newly added records
+            # (e.g. parallelly processing from beginning -> middle and ending -> middle
+            #       and as a final step, checking the "ending"+1 to see if there are
+            #       new records).
+            query = query.order_by(IndexRecord.updated_date)
 
             if ids:
                 query = query.filter(IndexRecord.did.in_(ids))
             else:
                 # only apply limit when ids is not provided
                 query = query.limit(limit)
 
+            if page is not None:
+                query = query.offset(limit * page)
+
             return [i.to_document_dict() for i in query]
 
     @staticmethod

openapis/swagger.yaml

@@ -204,6 +204,11 @@ paths:
           description: number of records to return for this page, default to 100
           required: false
           type: integer
+        - name: page
+          in: query
+          description: pagination support without relying on dids. offsets results by limit*page
+          required: false
+          type: integer
       produces:
         - application/json
       responses:
@@ -423,7 +428,7 @@ paths:
       parameters:
         - name: GUID
           in: path
-          description: The GUID to associate the new aliases with. 
+          description: The GUID to associate the new aliases with.
           required: true
           type: string
         - in: body
@@ -495,7 +500,7 @@ paths:
       parameters:
         - name: GUID
           in: path
-          description: The GUID to delete these aliases from. 
+          description: The GUID to delete these aliases from.
           required: true
           type: string
       responses:
@@ -506,7 +511,7 @@ paths:
           schema:
             $ref: '#/definitions/ErrorResponse'
       security:
-        - basic_auth: []      
+        - basic_auth: []
   '/index/{GUID}/aliases/{ALIAS}':
     delete:
       tags:
@@ -519,7 +524,7 @@ paths:
       parameters:
         - name: GUID
           in: path
-          description: The GUID to delete this alias from. 
+          description: The GUID to delete this alias from.
           required: true
           type: string
         - name: ALIAS
@@ -535,7 +540,7 @@ paths:
           schema:
             $ref: '#/definitions/ErrorResponse'
       security:
-        - basic_auth: []      
+        - basic_auth: []
 
   '/index/{GUID}/latest':
     get:
@@ -1022,7 +1027,7 @@ definitions:
       properties:
         aliases:
           type: array
-          items: 
+          items:
             type: object
             properties:
               value:

tests/test_client.py

@@ -848,6 +848,46 @@ def test_index_list_with_start(client, user):
     assert rec3["did"] in dids
 
 
+def test_index_list_with_page(client, user):
+    data = {
+        "did": "testprefix:11111111-1111-1111-1111-111111111111",
+        "form": "object",
+        "size": 123,
+        "urls": ["s3://endpointurl/bucket/key"],
+        "hashes": {"md5": "8b9942cf415384b27cadf1f4d2d682e5"},
+    }
+    res = client.post("/index/", json=data, headers=user)
+    assert res.status_code == 200
+    rec1 = res.json
+
+    data["did"] = "testprefix:22222222-2222-2222-2222-222222222222"
+    res = client.post("/index/", json=data, headers=user)
+    assert res.status_code == 200
+    rec2 = res.json
+
+    data["did"] = "testprefix:33333333-3333-3333-3333-333333333333"
+    res = client.post("/index/", json=data, headers=user)
+    assert res.status_code == 200
+    rec3 = res.json
+
+    res = client.get("/index/?page=0&limit=2")
+    assert res.status_code == 200
+    rec = res.json
+
+    dids = [record["did"] for record in rec["records"]]
+    assert len(rec["records"]) == 2
+    assert rec1["did"] in dids
+    assert rec2["did"] in dids
+
+    res = client.get("/index/?page=1&limit=2")
+    assert res.status_code == 200
+    rec = res.json
+
+    dids = [record["did"] for record in rec["records"]]
+    assert len(rec["records"]) == 1
+    assert rec3["did"] in dids
+
+
 def test_unauthorized_create(client):
     # test that unauthorized post throws 403 error
     data = get_doc()