This documentation site is for the versions of Synapse maintained by the Matrix.org Foundation (github.com/matrix-org/synapse), available under the Apache 2.0 licence.
A mapping provider is a Python class (loaded via a Python module) that
works out how to map attributes of a SSO response to Matrix-specific
user attributes. Details such as user ID localpart, displayname, and even avatar
URLs are all things that can be mapped from talking to a SSO service.
As an example, a SSO service may return the email address
"john.smith@example.com" for a user, whereas Synapse will need to figure out how
to turn that into a displayname when creating a Matrix user for this individual.
It may choose John Smith, or Smith, John [Example.com] or any number of
variations. As each Synapse configuration may want something different, this is
where SAML mapping providers come into play.
SSO mapping providers are currently supported for OpenID and SAML SSO
configurations. Please see the details below for how to implement your own.
It is up to the mapping provider whether the user should be assigned a predefined
Matrix ID based on the SSO attributes, or if the user should be allowed to
choose their own username.
In the first case - where users are automatically allocated a Matrix ID - it is
the responsibility of the mapping provider to normalise the SSO attributes and
map them to a valid Matrix ID. The specification for Matrix
IDs has some
information about what is considered valid.
If the mapping provider does not assign a Matrix ID, then Synapse will
automatically serve an HTML page allowing the user to pick their own username.
External mapping providers are provided to Synapse in the form of an external
Python module. You can retrieve this module from PyPI or elsewhere,
but it must be importable via Synapse (e.g. it must be in the same virtualenv
as Synapse). The Synapse config is then modified to point to the mapping provider
(and optionally provide additional configuration for it).
oidc_providers.user_mapping_provider.config allows you to provide custom
configuration options to the module. Check with the module's documentation for
what options it provides (if any). The options listed by default are for the
user mapping provider built in to Synapse. If using a custom module, you should
comment these options out and use those specified by the module instead.
A custom mapping provider must specify the following methods:
def __init__(self, parsed_config)
Arguments:
parsed_config - A configuration object that is the return value of the
parse_config method. You should set any configuration options needed by
the module here.
def parse_config(config)
This method should have the @staticmethod decoration.
Arguments:
config - A dict representing the parsed content of the
oidc_providers.user_mapping_provider.config homeserver config option.
Runs on homeserver startup. Providers should extract and validate
any option values they need here.
Whatever is returned will be passed back to the user mapping provider module's
__init__ method during construction.
def get_remote_user_id(self, userinfo)
Arguments:
userinfo - A authlib.oidc.core.claims.UserInfo object to extract user
information from.
This method must return a string, which is the unique, immutable identifier
for the user. Commonly the sub claim of the response.
token - A dictionary which includes information necessary to make
further requests to the OpenID provider.
failures - An int that represents the amount of times the returned
mxid localpart mapping has failed. This should be used
to create a deduplicated mxid localpart which should be
returned instead. For example, if this method returns
john.doe as the value of localpart in the returned
dict, and that is already taken on the homeserver, this
method will be called again with the same parameters but
with failures=1. The method should then return a different
localpart value, such as john.doe1.
Returns a dictionary with two keys:
localpart: A string, used to generate the Matrix ID. If this is
None, the user is prompted to pick their own username. This is only used
during a user's first login. Once a localpart has been associated with a
remote user ID (see get_remote_user_id) it cannot be updated.
confirm_localpart: A boolean. If set to True, when a localpart
string is returned from this method, Synapse will prompt the user to
either accept this localpart or pick their own username. Otherwise this
option has no effect. If omitted, defaults to False.
display_name: An optional string, the display name for the user.
emails: A list of strings, the email address(es) to associate with
this user. If omitted, defaults to an empty list.
saml2_config.user_mapping_provider.config allows you to provide custom
configuration options to the module. Check with the module's documentation for
what options it provides (if any). The options listed by default are for the
user mapping provider built in to Synapse. If using a custom module, you should
comment these options out and use those specified by the module instead.
A custom mapping provider must specify the following methods:
def __init__(self, parsed_config, module_api)
Arguments:
parsed_config - A configuration object that is the return value of the
parse_config method. You should set any configuration options needed by
the module here.
module_api - a synapse.module_api.ModuleApi object which provides the
stable API available for extension modules.
def parse_config(config)
This method should have the @staticmethod decoration.
Arguments:
config - A dict representing the parsed content of the
saml_config.user_mapping_provider.config homeserver config option.
Runs on homeserver startup. Providers should extract and validate
any option values they need here.
Whatever is returned will be passed back to the user mapping provider module's
__init__ method during construction.
def get_saml_attributes(config)
This method should have the @staticmethod decoration.
Arguments:
config - A object resulting from a call to parse_config.
Returns a tuple of two sets. The first set equates to the SAML auth
response attributes that are required for the module to function, whereas
the second set consists of those attributes which can be used if available,
but are not necessary.
saml_response - A saml2.response.AuthnResponse object to extract user
information from.
failures - An int that represents the amount of times the returned
mxid localpart mapping has failed. This should be used
to create a deduplicated mxid localpart which should be
returned instead. For example, if this method returns
john.doe as the value of mxid_localpart in the returned
dict, and that is already taken on the homeserver, this
method will be called again with the same parameters but
with failures=1. The method should then return a different
mxid_localpart value, such as john.doe1.
client_redirect_url - A string, the URL that the client will be
redirected to.
This method must return a dictionary, which will then be used by Synapse
to build a new user. The following keys are allowed:
mxid_localpart - A string, the mxid localpart of the new user. If this is
None, the user is prompted to pick their own username. This is only used
during a user's first login. Once a localpart has been associated with a
remote user ID (see get_remote_user_id) it cannot be updated.
displayname - The displayname of the new user. If not provided, will default to
the value of mxid_localpart.
emails - A list of emails for the new user. If not provided, will
default to an empty list.
Alternatively it can raise a synapse.api.errors.RedirectException to
redirect the user to another page. This is useful to prompt the user for
additional information, e.g. if you want them to provide their own username.
It is the responsibility of the mapping provider to either redirect back
to client_redirect_url (including any additional information) or to
complete registration using methods from the ModuleApi.