wsgicors 0.4

WSGI for Cross Origin Resource Sharing (CORS)

wsgicors

This is a WSGI middleware that answers CORS preflight requests and adds the needed header to the response. For CORS see: http://www.w3.org/TR/cors/

Usage

Either plug it in programmatically as in this pyramid example:

def app(global_config, **settings):
    """ This function returns a WSGI application.

    It is usually called by the PasteDeploy framework during
    ``paster serve``.
    """

    def get_root(request):
        return {}

    config = Configurator(root_factory=get_root, settings=settings)
    config.begin()
    # whatever it takes to config your app goes here
    config.end()

    from wsgicors import CORS
    return CORS(config.make_wsgi_app(), headers="*", methods="*", maxage="180", origin="*")

or plug it into your wsgi pipeline via paste ini to let it serve by waitress for instance:

[app:myapp]
use = egg:mysuperapp#app

###
# wsgi server configuration
###

[server:main]
use = egg:waitress#main
host = 0.0.0.0
port = 6543

[pipeline:main]
pipeline =
    cors
    myapp

[filter:cors]
use = egg:wsgicors#middleware
policy=free
free_origin=copy
free_headers=*
free_methods=*
free_maxage=180

policy=subdom
subdom_origin=example.com example2.com *.example.com
subdom_headers=*
subdom_methods=*
subdom_maxage=180

Keywords are:

• origin

• headers

• methods

• credentials

• maxage

for origin:

• use copy which will copy whatever origin the request comes from

• a space separated list of hostnames - they can also contain wildcards like * or ? (fnmatch lib is used for matching). If a match is found the original host is returned.

• any other literal will be be copied verbatim (like * for instance to allow every source)

for headers:

• use * which will allow whatever header is asked for

• any other literal will be be copied verbatim (like * for instance to allow every source)

for methods:

• use * which will allow whatever method is asked for

• any other literal will be be copied verbatim (like POST, PATCH, PUT, DELETE for instance)

for credentials:

• use true

• anything else will be ignored (that is no response header for Access-Control-Allow-Credentials is sent)

for maxage:

• give the number of seconds the answer can be used by a client, anything nonempty will be copied verbatim

As can be seen in the example above, a policy needs to be created with the policy keyword. The options need then be prefixed with the policy name and a _.

Changes

Version 0.4

• python3 compatibility

Version 0.3

• origin now takes space separated list of hostnames. They can be filename patterns like *.domain.tld

Version 0.2

• Access-Control-Allow-Credentials is now returned in the actual reponse if specified by policy

Credits

“wsgicors” is written and maintained by Norman Krämer.

Contributors

The following people contributed directly or indirectly to this project:

• Julien De Vos

• Ryan Shaw

Please add yourself here when you submit your first pull request.