Merge pull request #1447 from digitallyinduced/s0kil/compression-midd…

…leware

Compression Middleware Guide

.github/workflows/build.yml

@@ -34,12 +34,11 @@ jobs:
           echo "\$file_contents = file_get_contents('./default.nix');" >> replace.php
           echo '$new_content = preg_replace("/\".{40}\"/", "\"$argv[1]\"", $file_contents);' >> replace.php
           echo '$new_content_with_ref = preg_replace("/refs\/tags\/v\d+.\d+.\d+/", "${{ github.ref }}", $new_content);' >> replace.php
-          echo '$new_content_with_ref = str_replace("p.ihp", "p.ihp wreq mmark mmark-ext strip-ansi-escape stripe-signature stripe-concepts http-conduit units units-defs haskell-to-elm aeson-casing ihp-zip ihp-sentry minio-hs", $new_content_with_ref);' >> replace.php
+          echo '$new_content_with_ref = str_replace("p.ihp", "p.ihp wreq mmark mmark-ext strip-ansi-escape stripe-signature stripe-concepts http-conduit units units-defs haskell-to-elm aeson-casing ihp-zip ihp-sentry minio-hs hs-brotli wai-middleware-brotli", $new_content_with_ref);' >> replace.php
           echo "file_put_contents('./default.nix', \$new_content_with_ref);" >> replace.php
           echo "?>" >> replace.php
           php replace.php $GITHUB_SHA
           cat default.nix
           mv Makefile Makefile.old
           echo 'GHC_OPTIONS+= -rtsopts=all\n.SHELLFLAGS := -eu -o pipefail -c\n\n'|cat - Makefile.old > Makefile
           nix-shell --run "new-application Web && make build/bin/RunUnoptimizedProdServer"
-          

Guide/config.markdown

@@ -63,7 +63,7 @@ action MyAction = do
 
 ### Reading Environment Variables
 
-Inside `Config/Config.hs` you can use `env` to read environment variables. 
+Inside `Config/Config.hs` you can use `env` to read environment variables.
 
 ```haskell
 module Config where
@@ -152,3 +152,55 @@ config = do
     option $ CustomMiddleware $ addHeaders [("X-My-Header", "Custom WAI Middleware!")] . realIp
 ```
 
+### Compression Middleware
+We can compress assets using gzip or brotli.
+First, let's add the required Haskell dependencies:
+In your `default.nix` file, add:
+```nix
+        haskellDeps = p: with p; [
+            ...
+
+            # Wai Middleware
+            wai-middleware-brotli # <-- Add This Dependency
+            wai-extra # <-- And This One
+        ];
+```
+Run, `nix-shell --run 'make -B .envrc'` to update the environment.
+Once that succeeds, we can use it in your `Config/Config.hs`:
+
+Add two imports, one for Gzip compression, another for Brotli compression:
+```haskell
+module Config where
+...
+import Network.Wai.Middleware.Brotli -- <-- Add This Import
+import Network.Wai.Middleware.Gzip -- <-- And This One
+```
+
+And then create a function `compressionMiddleware` that combines (composes) Gzip and Brotli compression middleware's into one middleware:
+```haskell
+-- | Gzip And Brotli Compression Middleware
+compressionMiddleware :: CustomMiddleware
+compressionMiddleware =
+    let
+        -- With `GzipCompress` and `BrotliCompress` options, it will compress per request.
+        gzipSettings = def { gzipFiles = GzipCompress }
+        brotliSettings = defaultSettings { brotliFilesBehavior = BrotliCompress }
+    in
+        CustomMiddleware (gzip gzipSettings . brotli brotliSettings)
+
+```
+Lastly, we can use it as:
+```haskell
+config :: ConfigBuilder
+config = do
+    ...
+    option compressionMiddleware -- <-- Here we add our middleware
+```
+
+The default behavior for `GzipCompress` and `BrotliCompress` is to compress files on the fly.
+You can customize this behavior, take a look at the [brotli config](https://github.com/iand675/hs-brotli/blob/master/wai-middleware-brotli/src/Network/Wai/Middleware/Brotli.hs#L53-L66) and [gzip config](https://github.com/yesodweb/wai/blob/master/wai-extra/Network/Wai/Middleware/Gzip.hs#L62-L73).
+
+Also notice `CustomMiddleware (gzip gzipSettings . brotli brotliSettings)`, It's [important that brotli middleware wraps the gzip middleware](https://github.com/iand675/hs-brotli/blob/master/wai-middleware-brotli/src/Network/Wai/Middleware/Brotli.hs#L15-L17), so the responses are not compressed by both, if the client supports brotli, compress with brotli, otherwise gzip, fallback to no compression.
+
+By default all `text/*` content types will be compressed, including `application/json`, `application/javascript`, `application/ecmascript` and `image/x-icon`.
+Simply put, html, text, css, javascript, json and icons.

NixSupport/haskell-packages/hs-brotli.nix

@@ -0,0 +1,34 @@
+{ mkDerivation
+, base
+, bytestring
+, fetchgit
+, ghc-prim
+, lib
+, QuickCheck
+, quickcheck-instances
+, tasty
+, tasty-hunit
+, tasty-quickcheck
+}:
+let
+  nixpkgs = import <nixpkgs> { };
+in
+mkDerivation {
+  pname = "hs-brotli";
+  version = "0.1.0.0";
+  src = fetchgit {
+    url = "https://github.com/iand675/hs-brotli";
+    sha256 = "1i4qaqn79m4jcg16pdm222xy6x97r5fv8ikyykf1nl79hs0dajrh";
+    rev = "d7bce54b265883fb30a14d39d00cbf1c1308b2b1";
+    fetchSubmodules = true;
+  };
+  postUnpack = "sourceRoot+=/brotli; echo source root reset to $sourceRoot";
+  libraryHaskellDepends = [ base bytestring ghc-prim ];
+  librarySystemDepends = [ nixpkgs.brotli ];
+  libraryToolDepends = [ nixpkgs.pkg-config ];
+  libraryPkgconfigDepends = [ nixpkgs.brotli ];
+  testHaskellDepends = [ base bytestring QuickCheck quickcheck-instances tasty tasty-hunit tasty-quickcheck ];
+  homepage = "https://github.com/iand675/hs-brotli#readme";
+  description = "Compression and decompression in the brotli format";
+  license = lib.licenses.bsd3;
+}

NixSupport/haskell-packages/wai-middleware-brotli.nix

@@ -0,0 +1,34 @@
+{ mkDerivation
+, base
+, binary
+, bytestring
+, directory
+, fetchgit
+, filepath
+, hs-brotli
+, http-types
+, lib
+, mtl
+, tasty
+, tasty-hspec
+, tasty-hunit
+, unix
+, wai
+, wai-extra
+}:
+mkDerivation {
+  pname = "wai-middleware-brotli";
+  version = "0.1.0.0";
+  src = fetchgit {
+    url = "https://github.com/iand675/hs-brotli";
+    sha256 = "1i4qaqn79m4jcg16pdm222xy6x97r5fv8ikyykf1nl79hs0dajrh";
+    rev = "d7bce54b265883fb30a14d39d00cbf1c1308b2b1";
+    fetchSubmodules = true;
+  };
+  postUnpack = "sourceRoot+=/wai-middleware-brotli; echo source root reset to $sourceRoot";
+  libraryHaskellDepends = [ base binary bytestring directory filepath hs-brotli http-types unix wai ];
+  testHaskellDepends = [ base bytestring hs-brotli http-types mtl tasty tasty-hspec tasty-hunit wai wai-extra ];
+  homepage = "https://github.com/iand675/hs-brotli#readme";
+  description = "WAI middleware for brotli compression";
+  license = lib.licenses.bsd3;
+}