From 131f0548a7127ff5f9954b03680057d76b483f4b Mon Sep 17 00:00:00 2001
From: "bool.dev" <bool.dev@gmail.com>
Date: Thu, 3 Dec 2015 13:55:46 +0530
Subject: [PATCH] Proposed solution for #55, only certain files benefit from
 gzipping.

---
 docs/index.rst |  7 +++++++
 flask_s3.py    | 14 +++++++++++---
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/docs/index.rst b/docs/index.rst
index 64bbebf..6d60f22 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -232,6 +232,13 @@ uploading assets to S3.
 `FLASKS3_GZIP`              Compress all assets using GZIP and set the
                             corresponding Content-Type and Content-Encoding
                             headers on the S3 files.
+`FLASKS3_GZIP_ONLY_EXTS`    A list of file extensions that should be gzipped.
+                            `FLASKS3_GZIP` should be `True` for this to take effect.
+                            If mentioned and non-empty, then only files with the
+                            specified extensions are gzipped.
+                            Defaults to empty list, meaning all files will be
+                            gzipped.
+                            Eg:- `['.js', '.css']` will gzip only js and css files.
 `FLASKS3_FORCE_MIMETYPE`    Always set the Content-Type header on the S3 files
                             irrespective of gzipping. Defaults to `False`.
 =========================== ===================================================
diff --git a/flask_s3.py b/flask_s3.py
index 4d22864..db683a1 100644
--- a/flask_s3.py
+++ b/flask_s3.py
@@ -194,9 +194,11 @@ def _write_files(s3, app, static_url_loc, static_folder, files, bucket,
     """ Writes all the files inside a static folder to S3. """
     should_gzip = app.config.get('FLASKS3_GZIP')
     add_mime = app.config.get('FLASKS3_FORCE_MIMETYPE')
+    gzip_include_only = app.config.get('FLASKS3_GZIP_ONLY_EXTS')
     new_hashes = []
     static_folder_rel = _path_to_relative_url(static_folder)
     for file_path in files:
+        per_file_should_gzip = should_gzip
         asset_loc = _path_to_relative_url(file_path)
         full_key_name = _static_folder_path(static_url_loc, static_folder_rel,
                                             asset_loc)
@@ -224,10 +226,15 @@ def _write_files(s3, app, static_url_loc, static_folder, files, bucket,
                         for header, value in headers.iteritems():
                             h[header] = value
 
-            if should_gzip:
+            # check for extension, only if there are extensions provided
+            if per_file_should_gzip and gzip_include_only:
+                if os.path.splitext(file_path)[1] not in gzip_include_only:
+                    per_file_should_gzip = False
+
+            if per_file_should_gzip:
                 h["content-encoding"] = "gzip"
 
-            if add_mime or should_gzip and "content-type" not in h:
+            if add_mime or per_file_should_gzip and "content-type" not in h:
                 # When we use GZIP we have to explicitly set the content type
                 # or if the mime flag is True
                 (mimetype, encoding) = mimetypes.guess_type(file_path,
@@ -240,7 +247,7 @@ def _write_files(s3, app, static_url_loc, static_folder, files, bucket,
 
             with open(file_path) as fp:
                 metadata, params = split_metadata_params(merge_two_dicts(app.config['FLASKS3_HEADERS'], h))
-                if should_gzip:
+                if per_file_should_gzip:
                     compressed = StringIO()
                     z = gzip.GzipFile(os.path.basename(file_path), 'wb', 9,
                         compressed)
@@ -464,6 +471,7 @@ class FlaskS3(object):
                     ('FLASKS3_ONLY_MODIFIED', False),
                     ('FLASKS3_URL_STYLE', 'host'),
                     ('FLASKS3_GZIP', False),
+                    ('FLASKS3_GZIP_ONLY_EXTS', []),
                     ('FLASKS3_FORCE_MIMETYPE', False)]
 
         for k, v in defaults: