Add omahaproxy.py for accessing Chrome channel information from the command line.

tools/omahaproxy.py

+#!/usr/bin/env python
+# Copyright (c) 2013 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.
+
+"""Chrome Version Tool
+
+A simple script to scrape the Chrome channel information and print out the

[M-A Ruel, 2013/01/09 23:45:21]

Scrapes the ..

I know it's simple. :)

[scherkus (not reviewing), 2013/01/10 01:03:48]

Hah! Done!

+requested nugget of information.
+"""
+
+import optparse
+import os.path

[M-A Ruel, 2013/01/09 23:45:21]

Sort.

and in general we just "import os".

[scherkus (not reviewing), 2013/01/10 01:03:48]

Done.

+import json
+import urllib
+import string
+import sys
+
+URL = 'http://omahaproxy.appspot.com/json'

[M-A Ruel, 2013/01/09 23:45:21]

https?

[scherkus (not reviewing), 2013/01/10 01:03:48]

Done.

+

[M-A Ruel, 2013/01/09 23:45:21]

2 lines

[scherkus (not reviewing), 2013/01/10 01:03:48]

Done.

+def main():
+  try:
+    data = json.load(urllib.urlopen(URL))
+  except:

[M-A Ruel, 2013/01/09 23:45:21]

except Exception as e:
then print str(e)? It's useful to know what's happening.

[scherkus (not reviewing), 2013/01/10 01:03:48]

Done.

+    print 'Error: could not load %s' % URL
+    return 1
+
+  # Iterate to find out valid values for OS, channel, and field options.
+  oses = set()
+  channels = set()
+  fields = set()
+
+  for os_versions in data:
+    oses.add(os_versions['os'])
+
+    for version in os_versions['versions']:
+      for field in version:
+        if field == 'channel':
+          channels.add(version['channel'])
+        else:
+          fields.add(field)
+
+  oses = sorted(oses)
+  channels = sorted(channels)
+  fields = sorted(fields)
+
+  # Command line parsing fun begins!
+  usage = ('%prog [options]\n'
+           'Print out information about a particular Chrome channel.')
+  parser = optparse.OptionParser(usage=usage)
+
+  parser.add_option('-o', '--os',
+                    choices = oses,

[M-A Ruel, 2013/01/09 23:45:21]

No space around =

[scherkus (not reviewing), 2013/01/10 01:03:48]

Done.

+                    default = 'win',
+                    help = 'The operating system of interest: %s '
+                    '[default: %%default]' % ', '.join(oses))
+  parser.add_option('-c', '--channel',
+                    choices = channels,
+                    help = 'The channel of interest: %s' % ', '.join(channels))
+  parser.add_option('-f', '--field',
+                    choices = fields,
+                    default = 'version',
+                    help = 'The field of interest: %s '
+                    '[default: %%default] ' % ', '.join(fields))
+  (opts, args) = parser.parse_args()
+
+  if len(sys.argv) == 1:
+    parser.print_help()
+    return 1
+
+  if opts.os is None:

[M-A Ruel, 2013/01/09 23:45:21]

It can't be None? If someone specifies --os foo, I think it'll error out in
parse_args().

[scherkus (not reviewing), 2013/01/10 01:03:48]

You are correct!

This is also means I don't need the error handlers below either. I had this code
here before I discovered optparse had a choices feature.

I opted to add a default option for --channel (stable) so  we can leave
everything up to optparse now

+    print 'Error: invalid OS'
+    print
+    parser.print_help()
+    return 1
+
+  if opts.channel is None:
+    print 'Error: invalid channel'

[M-A Ruel, 2013/01/09 23:45:21]

parser.error('Please use --channel')

No need to return after since parser.error() calls sys.exit(2)

[scherkus (not reviewing), 2013/01/10 01:03:48]

No longer needed.

+    print
+    parser.print_help()
+    return 1
+
+  if opts.field is None:
+    print 'Error: invalid field'

[M-A Ruel, 2013/01/09 23:45:21]

Same

[scherkus (not reviewing), 2013/01/10 01:03:48]

No longer needed.

+    print
+    parser.print_help()
+    return 1
+
+  # Print out requested data if available.
+  for os_versions in data:
+    if os_versions['os'] != opts.os:
+      continue
+
+    for version in os_versions['versions']:
+      if version['channel'] != opts.channel:
+        continue
+
+      if opts.field not in version:
+        continue
+
+      print version[opts.field]
+      return 0
+
+  print 'Error: unable to find %s for Chrome %s %s.' % (
+      opts.field, opts.os, opts.channel)
+  return 1
+
+if __name__ == '__main__':
+  sys.exit(main())