Use JSONResponse class throughout

There seems to be something up with the ORJSONResponse class when used
with the CORS middleware. If ORJSONResponse is used then the CORS headers
aren't included in the response but if JSONResponse is used then they are.
Pretty weird... Additional bonus is that we really don't need to be using
orjson for this project, speed is not a problem when generating JSON
responses, so binning the orjson stuff makes it simpler and leaves us with
one less dependency :)

iiif/routers/iiif.py

@@ -1,6 +1,5 @@
 from fastapi import APIRouter
-from fastapi.responses import ORJSONResponse
-from starlette.responses import FileResponse
+from starlette.responses import FileResponse, JSONResponse
 
 from iiif.ops import IIIF_LEVEL, parse_params
 from iiif.processing import Task
@@ -11,7 +10,7 @@
 
 
 @router.get('/{identifier}/info.json')
-async def get_image_info(identifier: str) -> ORJSONResponse:
+async def get_image_info(identifier: str) -> JSONResponse:
     """
     IIIF image info endpoint compliant with the specification:
     https://iiif.io/api/image/3.0/#22-image-information-request-uri-syntax.
@@ -30,7 +29,7 @@ async def get_image_info(identifier: str) -> ORJSONResponse:
         'cache-control': f'max-age={profile.cache_for}',
         'link': f'<http://iiif.io/api/image/3/level{IIIF_LEVEL}.json>;rel="profile"'
     }
-    return ORJSONResponse(content=info_json, headers=headers)
+    return JSONResponse(content=info_json, headers=headers)
 
 
 @router.get('/{identifier}/{region}/{size}/{rotation}/{quality}.{fmt}')

iiif/web.py

@@ -4,7 +4,7 @@
 from PIL import Image
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
-from fastapi.responses import ORJSONResponse
+from starlette.responses import JSONResponse
 
 from iiif.routers import iiif, originals, simple
 from iiif.state import state
@@ -35,7 +35,7 @@ async def on_shutdown():
 
 
 @app.get('/status')
-async def status(full: bool = False) -> ORJSONResponse:
+async def status(full: bool = False) -> JSONResponse:
     """
     Returns the status of the server along with some stats about current resource usages.
     \f
@@ -53,7 +53,7 @@ async def status(full: bool = False) -> ORJSONResponse:
             for profile in state.profiles.values()
         }
     }
-    return ORJSONResponse(body, headers={'cache-control': 'no-store'})
+    return JSONResponse(body, headers={'cache-control': 'no-store'})
 
 
 # order matters here btw!

setup.py

@@ -21,7 +21,6 @@
     'fastapi~=0.63.0',
     'humanize~=3.4.1',
     f'jpegtran-cffi @ {jpegtran_url}',
-    'orjson~=3.5.2',
     'pillow~=8.2.0',
     'pyyaml~=5.4.1',
     'uvicorn[standard]~=0.13.4',