old_contents: # Software License Agreement (BSD License)
  #
  # Copyright (c) 2013, Open Source Robotics Foundation, Inc.
  # All rights reserved.
  #
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions
  # are met:
  #
  #  * Redistributions of source code must retain the above copyright
  #    notice, this list of conditions and the following disclaimer.
  #  * Redistributions in binary form must reproduce the above
  #    copyright notice, this list of conditions and the following
  #    disclaimer in the documentation and/or other materials provided
  #    with the distribution.
  #  * Neither the name of Open Source Robotics Foundation, Inc. nor
  #    the names of its contributors may be used to endorse or promote
  #    products derived from this software without specific prior
  #    written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  # FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  # COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  # BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  # POSSIBILITY OF SUCH DAMAGE.
  
  import time
  import urllib2
  
  
  def load_url(url, retry_on_503=3, retry_period=1):
      try:
          fh = urllib2.urlopen(url)
      except urllib2.HTTPError as e:
          if retry_on_503 and e.code == 503:
              time.sleep(retry_period)
              return load_url(url, retry_on_503 - 1, retry_period)
          raise
      except urllib2.URLError as e:
          e.reason += ' (%s)' % url
          raise
      return fh.read()
  
new_contents: # Software License Agreement (BSD License)
  #
  # Copyright (c) 2013, Open Source Robotics Foundation, Inc.
  # All rights reserved.
  #
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions
  # are met:
  #
  #  * Redistributions of source code must retain the above copyright
  #    notice, this list of conditions and the following disclaimer.
  #  * Redistributions in binary form must reproduce the above
  #    copyright notice, this list of conditions and the following
  #    disclaimer in the documentation and/or other materials provided
  #    with the distribution.
  #  * Neither the name of Open Source Robotics Foundation, Inc. nor
  #    the names of its contributors may be used to endorse or promote
  #    products derived from this software without specific prior
  #    written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  # FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  # COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  # BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  # POSSIBILITY OF SUCH DAMAGE.
  
  import time
  import urllib2
  
  
  def load_url(url, retry_on_503=2, retry_period=1, timeout=5):
      try:
          fh = urllib2.urlopen(url, timeout=timeout)
      except urllib2.HTTPError as e:
          if e.code == 503 and retry_on_503:
              time.sleep(retry_period)
              return load_url(url, retry_on_503 - 1, retry_period)
          raise
      except urllib2.URLError as e:
          raise urllib2.URLError(str(e) + ' (%s)' % url)
      return fh.read()
  
subject: add reasonable timeout to url loading, fix appending url to raised exceptions