Changelog for Falcon 0.2.0

Breaking Changes

  • The deprecated util.misc.percent_escape and util.misc.percent_unescape functions were removed. Please use the functions in the util.uri module instead.
  • The deprecated function, API.set_default_route, was removed. Please use sinks instead.
  • HTTPRangeNotSatisfiable no longer accepts a media_type parameter.
  • When using the comma-delimited list convention, req.get_param_as_list(…) will no longer insert placeholders, using the None type, for empty elements. For example, where previously the query string “foo=1,,3” would result in [‘1’, None, ‘3’], it will now result in [‘1’, ‘3’].

New & Improved

  • Since 0.1 we’ve added proper RTD docs to make it easier for everyone to get started with the framework. Over time we will continue adding content, and we would love your help!
  • Falcon now supports “wsgi.filewrapper”. You can assign any file-like object to and Falcon will use “wsgi.filewrapper” to more efficiently pipe the data to the WSGI server.
  • Support was added for automatically parsing requests containing “application/x-www-form-urlencoded” content. Form fields are now folded into req.params.
  • Custom Request and Response classes are now supported. You can specify custom types when instantiating falcon.API.
  • A new middleware feature was added to the framework. Middleware deprecates global hooks, and we encourage everyone to migrate as soon as possible.
  • A general-purpose dict attribute was added to Request. Middleware, hooks, and responders can now use req.context to share contextual information about the current request.
  • A new method, append_header, was added to falcon.API to allow setting multiple values for the same header using comma separation. Note that this will not work for setting cookies, but we plan to address this in the next release (0.3).
  • A new “resource” attribute was added to hooks. Old hooks that do not accept this new attribute are shimmed so that they will continue to function. While we have worked hard to minimize the performance impact, we recommend migrating to the new function signature to avoid any overhead.
  • Error response bodies now support XML in addition to JSON. In addition, the HTTPError serialization code was refactored to make it easier to implement a custom error serializer.
  • A new method, “set_error_serializer” was added to falcon.API. You can use this method to override Falcon’s default HTTPError serializer if you need to support custom media types.
  • Falcon’s testing base class, testing.TestBase was improved to facilitate Py3k testing. Notably, TestBase.simulate_request now takes an additional “decode” kwarg that can be used to automatically decode byte-string PEP-3333 response bodies.
  • An “add_link” method was added to the Response class. Apps can use this method to add one or more Link header values to a response.
  • Added two new properties, and req.subdomain, to make it easier to get at the hostname info in the request.
  • Allow a wider variety of characters to be used in query string params.
  • Internal APIs have been refactored to allow overriding the default routing mechanism. Further modularization is planned for the next release (0.3).
  • Changed req.get_param so that it behaves the same whether a list was specified in the query string using the HTML form style (in which each element is listed in a separate ‘key=val’ field) or in the more compact API style (in which each element is comma-separated and assigned to a single param instance, as in ‘key=val1,val2,val3’)
  • Added a convenience method, set_stream(…), to the Response class for setting the stream and its length at the same time, which should help people not forget to set both (and save a few keystrokes along the way).
  • Added several new error classes, including HTTPRequestEntityTooLarge, HTTPInvalidParam, HTTPMissingParam, HTTPInvalidHeader and HTTPMissingHeader.
  • Python 3.4 is now fully supported.
  • Various minor performance improvements


  • Ensure 100% test coverage and fix any bugs identified in the process.
  • Fix not recognizing the “bytes=” prefix in Range headers.
  • Make HTTPNotFound and HTTPMethodNotAllowed fully compliant, according to RFC 7231.
  • Fixed the default on_options responder causing a Cython type error.
  • URI template strings can now be of type unicode under Python 2.
  • When SCRIPT_NAME is not present in the WSGI environ, return an empty string for the property.
  • Global “after” hooks will now be executed even when a responder raises an error.
  • Fixed several minor issues regarding testing.create_environ(…)
  • Work around a wsgiref quirk, where if no content-length header is submitted by the client, wsgiref will set the value of that header to an empty string in the WSGI environ.
  • Resolved an issue causing several source files to not be Cythonized.
  • Docstrings have been edited for clarity and correctness.