Merge pull request #2 from sinisaos/async_version

async version experiment

Author: sinisaos

README.md

@@ -31,14 +31,15 @@ TaskModelOut: t.Any = create_pydantic_model(
 @app.get("/tasks/", response_model=t.List[TaskModelOut])
 async def tasks(
     request: Request,
-    __cursor: str,
+    __cursor: t.Optional[str] = None,
     __previous: t.Optional[str] = None,
 ):
     try:
-        cursor = request.query_params["__cursor"]
         previous = request.query_params["__previous"]
-        paginator = CursorPagination(cursor=cursor)
-        rows_result, headers_result = paginator.get_cursor_rows(Task, request)
+        paginator = CursorPagination(cursor=__cursor)
+        rows_result, headers_result = await paginator.get_cursor_rows(
+            Task, request
+        )
         rows = await rows_result.run()
         headers = headers_result
         response = JSONResponse(
@@ -48,9 +49,10 @@ async def tasks(
             },
         )
     except KeyError:
-        cursor = request.query_params["__cursor"]
-        paginator = CursorPagination(cursor=cursor)
-        rows_result, headers_result = paginator.get_cursor_rows(Task, request)
+        paginator = CursorPagination(cursor=__cursor)
+        rows_result, headers_result = await paginator.get_cursor_rows(
+            Task, request
+        )
         rows = await rows_result.run()
         headers = headers_result
         response = JSONResponse(

example/app.py

@@ -41,14 +41,17 @@
 @app.get("/tasks/", response_model=t.List[TaskModelOut])
 async def tasks(
     request: Request,
-    __cursor: str,
+    __cursor: t.Optional[str] = None,
     __previous: t.Optional[str] = None,
 ):
     try:
-        cursor = request.query_params["__cursor"]
         previous = request.query_params["__previous"]
-        paginator = CursorPagination(cursor=cursor, page_size=1, order_by="id")
-        rows_result, headers_result = paginator.get_cursor_rows(Task, request)
+        paginator = CursorPagination(
+            cursor=__cursor, page_size=10, order_by="id"
+        )
+        rows_result, headers_result = await paginator.get_cursor_rows(
+            Task, request
+        )
         rows = await rows_result.run()
         headers = headers_result
         response = JSONResponse(
@@ -58,9 +61,12 @@ async def tasks(
             },
         )
     except KeyError:
-        cursor = request.query_params["__cursor"]
-        paginator = CursorPagination(cursor=cursor, page_size=1, order_by="id")
-        rows_result, headers_result = paginator.get_cursor_rows(Task, request)
+        paginator = CursorPagination(
+            cursor=__cursor, page_size=10, order_by="id"
+        )
+        rows_result, headers_result = await paginator.get_cursor_rows(
+            Task, request
+        )
         rows = await rows_result.run()
         headers = headers_result
         response = JSONResponse(

piccolo_cursor_pagination/__init__.py

@@ -1 +0,0 @@
-__VERSION__ = "0.1.0"

piccolo_cursor_pagination/pagination.py

@@ -24,7 +24,7 @@ class CursorPagination:
     page_size: int = 15
     order_by: str = "-id"
 
-    def get_cursor_rows(self, table: t.Type[Table], request: Request):
+    async def get_cursor_rows(self, table: t.Type[Table], request: Request):
         # headers to adding next_cursor
         headers: t.Dict[str, str] = {}
 
@@ -37,7 +37,7 @@ def get_cursor_rows(self, table: t.Type[Table], request: Request):
             query = query.limit(self.page_size + 1)
 
             # decoded query params cursor
-            decoded_cursor = self.decode_cursor(self.cursor, table)
+            decoded_cursor = await self.decode_cursor(self.cursor, table)
 
             try:
                 # preform operation if previous in query params
@@ -50,15 +50,15 @@ def get_cursor_rows(self, table: t.Type[Table], request: Request):
                         .order_by(table._meta.primary_key, ascending=False)
                         .limit(self.page_size)
                     )
-                    rows = query.run_sync()
+                    rows = await query.run()
                     try:
                         # set new value to next_cursor
                         next_cursor = self.encode_cursor(str(rows[-1]["id"]))
                         headers["cursor"] = next_cursor
                         # return empty cursor if no more results
-                        last_row = table.select().limit(1).first().run_sync()
+                        last_row = await table.select().limit(1).first().run()
                         if (
-                            self.decode_cursor(next_cursor, table)
+                            await self.decode_cursor(next_cursor, table)
                             == last_row["id"]
                         ):
                             headers["cursor"] = ""
@@ -69,7 +69,7 @@ def get_cursor_rows(self, table: t.Type[Table], request: Request):
                 query = query.where(
                     table._meta.primary_key >= int(decoded_cursor)
                 ).limit(self.page_size + 1)
-                rows = query.run_sync()
+                rows = await query.run()
                 # set new value to next_cursor
                 next_cursor = self.encode_cursor(str(rows[-1]["id"]))
                 headers["cursor"] = next_cursor
@@ -83,7 +83,7 @@ def get_cursor_rows(self, table: t.Type[Table], request: Request):
             query = query.limit(self.page_size + 1)
 
             # decoded query params cursor
-            decoded_cursor = self.decode_cursor(self.cursor, table)
+            decoded_cursor = await self.decode_cursor(self.cursor, table)
 
             try:
                 # preform operation if previous in query params
@@ -96,21 +96,21 @@ def get_cursor_rows(self, table: t.Type[Table], request: Request):
                         .order_by(table._meta.primary_key, ascending=True)
                         .limit(self.page_size)
                     )
-                    rows = query.run_sync()
+                    rows = await query.run()
                     try:
                         # set new value to next_cursor
                         next_cursor = self.encode_cursor(str(rows[-1]["id"]))
                         headers["cursor"] = next_cursor
                         # return empty cursor if no more results
-                        last_row = (
+                        last_row = await (
                             table.select()
                             .limit(1)
                             .order_by(table._meta.primary_key, ascending=False)
                             .first()
-                            .run_sync()
+                            .run()
                         )
                         if (
-                            self.decode_cursor(next_cursor, table)
+                            await self.decode_cursor(next_cursor, table)
                             == last_row["id"]
                         ):
                             headers["cursor"] = ""
@@ -121,7 +121,7 @@ def get_cursor_rows(self, table: t.Type[Table], request: Request):
                 query = query.where(
                     table._meta.primary_key <= int(decoded_cursor)
                 ).limit(self.page_size + 1)
-                rows = query.run_sync()
+                rows = await query.run()
                 # set new value to next_cursor
                 next_cursor = self.encode_cursor(str(rows[-1]["id"]))
                 headers["cursor"] = next_cursor
@@ -134,17 +134,17 @@ def encode_cursor(self, cursor: str) -> str:
         base64_bytes = base64.b64encode(cursor_bytes)
         return base64_bytes.decode("ascii")
 
-    def decode_cursor(self, cursor: str, table: t.Type[Table]) -> int:
+    async def decode_cursor(self, cursor: str, table: t.Type[Table]) -> int:
+        if cursor is None:
+            cursor = ""
         base64_bytes = cursor.encode("ascii")
         cursor_bytes = base64.b64decode(base64_bytes)
-        # we provide initial cursor like this because
-        # we cannot pass empty string to FastAPI openapi
-        initial_cursor = (
+        initial_cursor = await (
             table.select()
             .order_by(table._meta.primary_key, ascending=False)
             .limit(1)
             .first()
-            .run_sync()
+            .run()
         )
         return (
             int(cursor_bytes.decode("ascii") or 0)

tests/test_cursor_pagination_asc.py

@@ -24,16 +24,18 @@ def get_readable(cls):
 
 
 @app.get("/movies/")
-def movies(
+async def movies(
     request: Request,
     __cursor: str,
     __previous: t.Optional[str] = None,
 ):
     try:
         cursor = request.query_params["__cursor"]
         paginator = CursorPagination(cursor=cursor, page_size=1, order_by="id")
-        rows_result, headers_result = paginator.get_cursor_rows(Movie, request)
-        rows = rows_result.run_sync()
+        rows_result, headers_result = await paginator.get_cursor_rows(
+            Movie, request
+        )
+        rows = await rows_result.run()
         headers = headers_result
         response = JSONResponse(
             {"rows": rows[::-1]},
@@ -44,8 +46,10 @@ def movies(
     except KeyError:
         cursor = request.query_params["__cursor"]
         paginator = CursorPagination(cursor=cursor, page_size=1, order_by="id")
-        rows_result, headers_result = paginator.get_cursor_rows(Movie, request)
-        rows = rows_result.run_sync()
+        rows_result, headers_result = await paginator.get_cursor_rows(
+            Movie, request
+        )
+        rows = await rows_result.run()
         headers = headers_result
         response = JSONResponse(
             {"rows": rows},

tests/test_cursor_pagination_desc.py

@@ -24,7 +24,7 @@ def get_readable(cls):
 
 
 @app.get("/movies/")
-def movies(
+async def movies(
     request: Request,
     __cursor: str,
     __previous: t.Optional[str] = None,
@@ -34,8 +34,10 @@ def movies(
         paginator = CursorPagination(
             cursor=cursor, page_size=1, order_by="-id"
         )
-        rows_result, headers_result = paginator.get_cursor_rows(Movie, request)
-        rows = rows_result.run_sync()
+        rows_result, headers_result = await paginator.get_cursor_rows(
+            Movie, request
+        )
+        rows = await rows_result.run()
         headers = headers_result
         response = JSONResponse(
             {"rows": rows[::-1]},
@@ -48,8 +50,10 @@ def movies(
         paginator = CursorPagination(
             cursor=cursor, page_size=1, order_by="-id"
         )
-        rows_result, headers_result = paginator.get_cursor_rows(Movie, request)
-        rows = rows_result.run_sync()
+        rows_result, headers_result = await paginator.get_cursor_rows(
+            Movie, request
+        )
+        rows = await rows_result.run()
         headers = headers_result
         response = JSONResponse(
             {"rows": rows},