Server throws HTTP 500 error when there is no accept header in the request #402
Description
To reproduce the error, use this curl command:
curl "http://grlc.io/api-git/CLARIAH/grlc-queries/defaults?genre=http%3A%2F%2Fdbpedia.org%2Fresource%2FRock_music&endpoint=https%3A%2F%2Fdbpedia.org%2Fsparql" -H "accept:"
The verbose output showing request and response headers:
* Trying 213.187.244.59:80...
* Connected to grlc.io (213.187.244.59) port 80 (#0)
> GET /api-git/CLARIAH/grlc-queries/defaults?genre=http%3A%2F%2Fdbpedia.org%2Fresource%2FRock_music&endpoint=https%3A%2F%2Fdbpedia.org%2Fsparql HTTP/1.1
> Host: grlc.io
> User-Agent: curl/7.87.0
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 500 INTERNAL SERVER ERROR
< Date: Mon, 19 Jun 2023 12:19:18 GMT
< Content-Type: text/html; charset=utf-8
< Content-Length: 290
< Connection: keep-alive
< Server: gunicorn/19.6.0
< Access-Control-Allow-Origin: *
<
{ [290 bytes data]
* Connection #0 to host grlc.io left intact
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<title>500 Internal Server Error</title>
<h1>Internal Server Error</h1>
<p>The server encountered an internal error and was unable to complete your request. Either the server is overloaded or there is an error in the application.</p>
Running a local instance of grlc, I see these kind of errors in the application logs:
/usr/local/lib/python3.6/site-packages/grlc/fileLoaders.py:272: YAMLLoadWarning: calling yaml.load() without Loader=... is deprecated, as the default Loader is unsafe. Please read https://msg.pyyaml.org/load for full details.
self.spec = yaml.load(resp.text)
/usr/local/lib/python3.6/site-packages/grlc/gquery.py:277: YAMLLoadWarning: calling yaml.load() without Loader=... is deprecated, as the default Loader is unsafe. Please read https://msg.pyyaml.org/load for full details.
query_metadata = yaml.load(yaml_string)
ERROR:Exception on /api-url/company-detail [GET]
Traceback (most recent call last):
File "/usr/local/lib/python3.6/site-packages/flask/app.py", line 2292, in wsgi_app
response = self.full_dispatch_request()
File "/usr/local/lib/python3.6/site-packages/flask/app.py", line 1815, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/usr/local/lib/python3.6/site-packages/flask_cors/extension.py", line 161, in wrapped_function
return cors_after_request(app.make_response(f(*args, **kwargs)))
File "/usr/local/lib/python3.6/site-packages/flask/app.py", line 1718, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/usr/local/lib/python3.6/site-packages/flask/_compat.py", line 35, in reraise
raise value
File "/usr/local/lib/python3.6/site-packages/flask/app.py", line 1813, in full_dispatch_request
rv = self.dispatch_request()
File "/usr/local/lib/python3.6/site-packages/flask/app.py", line 1799, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/usr/local/lib/python3.6/site-packages/grlc/server.py", line 125, in query_param
return query(user=None, repo=None, query_name=query_name, spec_url=spec_url, content=content)
File "/usr/local/lib/python3.6/site-packages/grlc/server.py", line 47, in query
glogger.debug("Request accept header: " + request.headers["Accept"])
File "/usr/local/lib/python3.6/site-packages/werkzeug/datastructures.py", line 1463, in __getitem__
return _unicodify_header_value(self.environ["HTTP_" + key])
KeyError: 'HTTP_ACCEPT'
If the accept header is expected/required, it'd be more appropriate to return a 4XX response code.
Otherwise, if no accept header is present, then serve JSON by default.