params.py
#

A middleware for parsing GET and POST params.

 
import re
from pump.util import codec
#

Middleware to parse GET and POST params. Adds the following keys to the request:

  • get_params
  • post_params
  • params

You can specify an encoding to decode the URL-encoded params with. If not specified, uses the character encoding specified in the request, or UTF-8 by default.

 
def wrap_params(app, options={}):
# 
  def wrapped_app(request):
    encoding = (options.get('encoding') or
                request.get('character_encoding') or
                "utf8")
    if not request.get('get_params'):
      request = parse_get_params(request, encoding)
    if not request.get('post_params'):
      request = parse_post_params(request, encoding)
    return app(request)

  return wrapped_app
#

Parse params from the query string.

 
def parse_get_params(request, encoding):
  if request.get("query_string"):
    params = parse_params(request["query_string"], encoding)
  else:
    params = {}

  return _recursive_merge(request, {'get_params': params, 'params': params})
#

Parse params from the request body.

 
def parse_post_params(request, encoding):
  if _does_have_urlencoded_form(request) and request.get("body"):
    params = parse_params(request["body"].read(), encoding)
  else:
    params = {}

  return _recursive_merge(request, {'post_params': params, 'params': params})
#

Parse params from a string (e.g. "a=b&c=d") into a dict.

 
def parse_params(params_string, encoding):
# 
  def _parse(params_dict, encoded_param):
    match = re.compile(r'([^=]+)=(.*)').match(encoded_param)
    if not match:
      return params_dict
    key, val = match.groups()
    return set_param(params_dict,
      codec.url_decode(key, encoding), codec.url_decode(val or '', encoding))

  return reduce(_parse, params_string.split('&'), {})
#

Set a value for a key. If it already has a value, make a list of values.

 
def set_param(params, key, val):
  cur = params.get(key)
  if cur:
    if isinstance(cur, list):
      params[key].append(val)
    else:
      params[key] = [cur, val]
  else:
    params[key] = val
  return params
#

Check whether a urlencoded form was submitted.

 
def _does_have_urlencoded_form(request):
  return request.get('content_type', '').startswith(
    'application/x-www-form-urlencoded')
#

Merge two dicts recursively.

 
def _recursive_merge(x, y):
  z = x.copy()
  for key, val in y.iteritems():
    if isinstance(val, dict):
      if not z.has_key(key):
        z[key] = {}
      z[key] = _recursive_merge(z[key], val)
    else:
      z[key] = val
  return z