Add a script for converting a raw binary feed response to textproto

Bug: 1044139
Change-Id: I0eac7262fec61f477a31a61da5b277b685a32909
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2088409
Commit-Queue: Ian Wells <iwells@chromium.org>
Reviewed-by: Dan H <harringtond@chromium.org>
Cr-Commit-Position: refs/heads/master@{#753316}

components/feed/core/v2/tools/feed_response_to_textproto.sh

+#!/bin/bash
+# Copyright 2020 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+#
+# Converts a Feed HTTP response from binary to text using proto definitions from
+# Chromium.
+#
+# Usage: feed_response_to_textproto.sh <in.binarypb> <out.textproto>
+
+IN_FILE=$1
+OUT_FILE=$2
+TMP_FILE=/tmp/trimmedfeedresponse.binarypb
+
+CHROMIUM_SRC=$(realpath $(dirname $(readlink -f $0))/../../../../..)
+FEEDPROTO="$CHROMIUM_SRC/components/feed/core/proto"
+
+# Responses start with a 4-byte length value that must be removed.
+tail -c +4 $IN_FILE > $TMP_FILE
+
+python3 $CHROMIUM_SRC/components/feed/core/v2/tools/textpb_to_binarypb.py \
+  --chromium_path=$CHROMIUM_SRC \
+  --output_file=$OUT_FILE \
+  --source_file=$TMP_FILE \
+  --direction=reverse

components/feed/core/v2/tools/textpb_to_binarypb.py

@@ -34,9 +34,31 @@ flags.DEFINE_string('source_file', '',
 flags.DEFINE_string('message',
                     DEFAULT_MESSAGE,
                     'The message to look for in source_file.')
+flags.DEFINE_string('direction', 'forward',
+                    'Set --direction=reverse to convert binary to text.')
 
 COMPONENT_FEED_PROTO_PATH = 'components/feed/core/proto'
 
+def text_to_binary():
+  with open(FLAGS.source_file, mode='r') as file:
+    value_text_proto = file.read()
+
+  encoded = protoc_util.encode_proto(value_text_proto, FLAGS.message,
+                                     FLAGS.chromium_path,
+                                     COMPONENT_FEED_PROTO_PATH)
+  with open(FLAGS.output_file, mode='wb') as file:
+    file.write(encoded)
+
+def binary_to_text():
+  with open(FLAGS.source_file, mode='rb') as file:
+    value_text_proto = file.read()
+
+  encoded = protoc_util.decode_proto(value_text_proto, FLAGS.message,
+                                     FLAGS.chromium_path,
+                                     COMPONENT_FEED_PROTO_PATH)
+
+  with open(FLAGS.output_file, mode='w') as file:
+    file.write(encoded)
 
 def main(argv):
   if len(argv) > 1:
@@ -47,16 +69,13 @@ def main(argv):
     raise app.UsageError('source_file flag must be set.')
   if not FLAGS.output_file:
     raise app.UsageError('output_file flag must be set.')
+  if FLAGS.direction != 'forward' and FLAGS.direction != 'reverse':
+    raise app.UsageError('direction must be forward or reverse')
 
-  with open(FLAGS.source_file) as file:
-    value_text_proto = file.read()
-
-  encoded = protoc_util.encode_proto(value_text_proto, FLAGS.message,
-                                     FLAGS.chromium_path,
-                                     COMPONENT_FEED_PROTO_PATH)
-  with open(FLAGS.output_file, 'wb') as file:
-    file.write(encoded)
-
+  if FLAGS.direction == 'forward':
+    text_to_binary()
+  elif FLAGS.direction == 'reverse':
+    binary_to_text()
 
 if __name__ == '__main__':
   app.run(main)