Refactor module MediaType.hs to use Network.HTTP.Media

[taimoorzaeem]

Description of issue

The MediaType.hs module is quite verbose and the code looks kind of ugly. For instance:

postgrest/src/PostgREST/MediaType.hs

Lines 36 to 50 in 87d6a0d

	instance Eq MediaType where
	MTApplicationJSON == MTApplicationJSON = True
	MTArrayJSONStrip == MTArrayJSONStrip = True
	MTSingularJSON x == MTSingularJSON y = x == y
	MTGeoJSON == MTGeoJSON = True
	MTTextCSV == MTTextCSV = True
	MTTextPlain == MTTextPlain = True
	MTTextXML == MTTextXML = True
	MTOpenAPI == MTOpenAPI = True
	MTUrlEncoded == MTUrlEncoded = True
	MTOctetStream == MTOctetStream = True
	MTAny == MTAny = True
	MTOther x == MTOther y = x == y
	MTPlan{} == MTPlan{} = True
	_ == _ = False

Solution

The module could be refactored to use Network.HTTP.Media. This would let us remove the above mentioned part.

[steve-chavez]

Maybe we're being too strict with the types for media type parsing. For example https://httpbin.org/ behaves like:

$ curl -H "Content-Type: application/json; any=44; thing=33" 'https://httpbin.org/post' -d @- <<JSON
{"a": 3}
JSON

{
  "args": {}, 
  "data": "{\"a\": 3}", 
  "files": {}, 
  "form": {}, 
  "headers": {
    "Accept": "*/*", 
    "Content-Length": "8", 
    "Content-Type": "application/json; any=44; thing=33", 
    "Host": "httpbin.org", 
    "User-Agent": "curl/7.81.0", 
    "X-Amzn-Trace-Id": "Root=1-64de9754-6ca0259374ed248d769677e9"
  }, 
  "json": {
    "a": 3
  }, 
  "origin": "179.6.5.245", 
  "url": "https://httpbin.org/post"
}

Meaning it ignores unknown media type parameters.

[taimoorzaeem]

Well, the RFC 6838 states that we shouldn't add parameters to standard media types. However, yes I think we are being a little bit too strict for discarding the parameters for our custom media types. However parsing these parameters complicate the code. For example, the way MTPlan media type is handled.