Merge pull request #44 from andrewsnowden/gzip-compression

Gzip compression

docs/index.rst

@@ -229,6 +229,9 @@ uploading assets to S3.
                             your S3 bucket to force all files to upload again.
 `S3_CACHE_CONTROL`          **Deprecated**. Please use `S3_HEADERS` instead.
 `S3_USE_CACHE_CONTROL`      **Deprecated**. Please use `S3_HEADERS` instead.
+`S3_GZIP`                   Compress all assets using GZIP and set the
+                            corresponding Content-Type and Content-Encoding
+                            headers on the S3 files.
 =========================== ===================================================
 
 .. _debug: http://flask.pocoo.org/docs/config/#configuration-basics

flask_s3.py

@@ -3,6 +3,12 @@ import json
 import logging
 import os
 import re
+import gzip
+try:
+    from cStringIO import StringIO
+except ImportError:
+    from io import StringIO
+import mimetypes
 from collections import defaultdict
 
 import boto3
@@ -175,6 +181,7 @@ def _static_folder_path(static_url, static_folder, static_asset):
 def _write_files(s3, app, static_url_loc, static_folder, files, bucket,
                  ex_keys=None, hashes=None):
     """ Writes all the files inside a static folder to S3. """
+    should_gzip = app.config.get('S3_GZIP')
     new_hashes = []
     static_folder_rel = _path_to_relative_url(static_folder)
     for file_path in files:
@@ -206,11 +213,34 @@ def _write_files(s3, app, static_url_loc, static_folder, files, bucket,
                         for header, value in headers.iteritems():
                             h[header] = value
 
+            if should_gzip:
+                h["content-encoding"] = "gzip"
+                if "content-type" not in h:
+                    # When we use GZIP we have to explicitly set the content type
+                    (mimetype, encoding) = mimetypes.guess_type(file_path,
+                        False)
+                    if mimetype:
+                        h["content-type"] = mimetype
+                    else:
+                        logger.warn("Unable to detect mimetype for %s" %
+                            file_path)
+
             with open(file_path) as fp:
                 metadata, params = split_metadata_params(merge_two_dicts(app.config['S3_HEADERS'], h))
+                if should_gzip:
+                    compressed = StringIO()
+                    z = gzip.GzipFile(os.path.basename(file_path), 'wb', 9,
+                        compressed)
+                    z.write(fp.read())
+                    z.close()
+
+                    data = compressed.getvalue()
+                else:
+                    data = fp.read()
+
                 s3.put_object(Bucket=bucket,
                               Key=key_name,
-                              Body=fp.read(),
+                              Body=data,
                               ACL="public-read",
                               Metadata=metadata,
                               **params)
@@ -370,7 +400,8 @@ class FlaskS3(object):
                     ('S3_HEADERS', {}),
                     ('S3_FILEPATH_HEADERS', {}),
                     ('S3_ONLY_MODIFIED', False),
-                    ('S3_URL_STYLE', 'host')]
+                    ('S3_URL_STYLE', 'host'),
+                    ('S3_GZIP', False)]
 
         for k, v in defaults:
             app.config.setdefault(k, v)