remove brotli compression (#2967)

Although brotli itself is MIT-licensed, the Haskell brotli library that provides bindings to it is GPL-licensed, so we cannot use it unless we get a response on haskell-hvr/brotli#1.

docs/graphql/manual/deployment/compression.rst

@@ -8,9 +8,7 @@ HTTP Compression
 
 The Hasura GraphQL Engine supports HTTP compression.
 The server looks for the ``Accept-Encoding`` header in request.
-If the header contains ``br`` then the server uses `Brotli <https://en.wikipedia.org/wiki/Brotli>`__ compression else if the header contains
-``gzip`` then the server uses `Gzip <https://en.wikipedia.org/wiki/Gzip>`__ compression.
-If both values are present then the server prefers ``Brotli`` over ``Gzip``.
-Also, the server sets the ``Content-Encoding`` response header value to ``br`` for ``Brotli`` compression or ``gzip`` for ``Gzip`` compression.
+If the header contains ``gzip`` then the server uses `Gzip <https://en.wikipedia.org/wiki/Gzip>`__ compression.
+Also, the server sets the ``Content-Encoding`` response header value to ``gzip``.
 
 **Only responses from "/v1/query" and "/v1/graphql" endpoints are compressed.**

server/graphql-engine.cabal

@@ -148,7 +148,6 @@ library
 
                      -- HTTP compression
                      , zlib
-                     , brotli
 
   exposed-modules:     Hasura.Prelude
                      , Hasura.Logging

server/src-lib/Hasura/Server/Compression.hs

@@ -7,22 +7,19 @@ where
 
 import           Hasura.Prelude
 
-import           Hasura.Server.Utils       (brHeader, gzipHeader)
+import           Hasura.Server.Utils       (gzipHeader)
 
-import qualified Codec.Compression.Brotli  as BR
 import qualified Codec.Compression.GZip    as GZ
 import qualified Data.ByteString.Lazy      as BL
 import qualified Data.Text                 as T
 import qualified Network.HTTP.Types.Header as NH
 
 data CompressionType
   = CTGZip
-  | CTBrotli
   deriving (Show, Eq)
 
 compressionTypeToTxt :: CompressionType -> T.Text
 compressionTypeToTxt CTGZip   = "gzip"
-compressionTypeToTxt CTBrotli = "brotli"
 
 compressResponse
   :: NH.RequestHeaders
@@ -31,14 +28,14 @@ compressResponse
 compressResponse reqHeaders unCompressedResp =
   let compressionTypeM = getRequestedCompression reqHeaders
       appendCompressionType (res, headerM) = (res, headerM, compressionTypeM)
+      gzipCompressionParams =
+        GZ.defaultCompressParams{GZ.compressLevel = GZ.compressionLevel 1}
   in appendCompressionType $ case compressionTypeM of
-       Just CTBrotli -> (BR.compress unCompressedResp, Just brHeader)
-       Just CTGZip   -> (GZ.compress unCompressedResp, Just gzipHeader)
-       Nothing       -> (unCompressedResp, Nothing)
+       Just CTGZip -> (GZ.compressWith gzipCompressionParams unCompressedResp, Just gzipHeader)
+       Nothing     -> (unCompressedResp, Nothing)
 
 getRequestedCompression :: NH.RequestHeaders -> Maybe CompressionType
 getRequestedCompression reqHeaders
-  | "br" `elem` acceptEncodingVals   = Just CTBrotli
   | "gzip" `elem` acceptEncodingVals = Just CTGZip
   | otherwise                        = Nothing
   where

server/tests-py/test_compression.py

@@ -63,27 +63,16 @@ def test_gzip_compression_v1_query(self, hge_ctx):
         resp = self._make_post(hge_ctx, url, q, self.gzip_header)
         self._assert_gzip(resp, exp_resp)
 
-    def test_brotli_compression_graphql(self, hge_ctx):
-        url, q, exp_resp = self._get_config(self.dir() + '/graphql_query.yaml')
-        resp = self._make_post(hge_ctx, url, q, self.brotli_header)
-        self._assert_brotli(resp, exp_resp)
-
-    def test_brotli_compression_v1_query(self, hge_ctx):
-        url, q, exp_resp = self._get_config(self.dir() + '/v1_query.yaml')
-        resp = self._make_post(hge_ctx, url, q, self.brotli_header)
-        self._assert_brotli(resp, exp_resp)
 
-
-    # If gzip and brotli encoding are requested the server prefers brotli
     def test_gzip_brotli_graphql_query(self, hge_ctx):
         url, q, exp_resp = self._get_config(self.dir() + '/graphql_query.yaml')
         resp = self._make_post(hge_ctx, url, q, self.gzip_brotli_header)
-        self._assert_brotli(resp, exp_resp)
+        self._assert_gzip(resp, exp_resp)
 
     def test_gzip_brotli_v1_query(self, hge_ctx):
         url, q, exp_resp = self._get_config(self.dir() + '/v1_query.yaml')
         resp = self._make_post(hge_ctx, url, q, self.gzip_brotli_header)
-        self._assert_brotli(resp, exp_resp)
+        self._assert_gzip(resp, exp_resp)
 
     @classmethod
     def dir(cls):