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                        <h1 id="password-auth-provider-callbacks"><a class="header" href="#password-auth-provider-callbacks">Password auth provider callbacks</a></h1>
<p>Password auth providers offer a way for server administrators to integrate
their Synapse installation with an external authentication system. The callbacks can be
registered by using the Module API's <code>register_password_auth_provider_callbacks</code> method.</p>
<h2 id="callbacks"><a class="header" href="#callbacks">Callbacks</a></h2>
<h3 id="auth_checkers"><a class="header" href="#auth_checkers"><code>auth_checkers</code></a></h3>
<p><em>First introduced in Synapse v1.46.0</em></p>
<pre><code class="language-python">auth_checkers: Dict[Tuple[str, Tuple[str, ...]], Callable]
</code></pre>
<p>A dict mapping from tuples of a login type identifier (such as <code>m.login.password</code>) and a
tuple of field names (such as <code>(&quot;password&quot;, &quot;secret_thing&quot;)</code>) to authentication checking
callbacks, which should be of the following form:</p>
<pre><code class="language-python">async def check_auth(
    user: str,
    login_type: str,
    login_dict: &quot;synapse.module_api.JsonDict&quot;,
) -&gt; Optional[
    Tuple[
        str, 
        Optional[Callable[[&quot;synapse.module_api.LoginResponse&quot;], Awaitable[None]]]
    ]
]
</code></pre>
<p>The login type and field names should be provided by the user in the
request to the <code>/login</code> API. <a href="https://matrix.org/docs/spec/client_server/latest#authentication-types">The Matrix specification</a>
defines some types, however user defined ones are also allowed.</p>
<p>The callback is passed the <code>user</code> field provided by the client (which might not be in
<code>@username:server</code> form), the login type, and a dictionary of login secrets passed by
the client.</p>
<p>If the authentication is successful, the module must return the user's Matrix ID (e.g. 
<code>@alice:example.com</code>) and optionally a callback to be called with the response to the
<code>/login</code> request. If the module doesn't wish to return a callback, it must return <code>None</code>
instead.</p>
<p>If the authentication is unsuccessful, the module must return <code>None</code>.</p>
<p>If multiple modules register an auth checker for the same login type but with different
fields, Synapse will refuse to start.</p>
<p>If multiple modules register an auth checker for the same login type with the same fields,
then the callbacks will be executed in order, until one returns a Matrix User ID (and
optionally a callback). In that case, the return value of that callback will be accepted
and subsequent callbacks will not be fired. If every callback returns <code>None</code>, then the
authentication fails.</p>
<h3 id="check_3pid_auth"><a class="header" href="#check_3pid_auth"><code>check_3pid_auth</code></a></h3>
<p><em>First introduced in Synapse v1.46.0</em></p>
<pre><code class="language-python">async def check_3pid_auth(
    medium: str, 
    address: str,
    password: str,
) -&gt; Optional[
    Tuple[
        str, 
        Optional[Callable[[&quot;synapse.module_api.LoginResponse&quot;], Awaitable[None]]]
    ]
]
</code></pre>
<p>Called when a user attempts to register or log in with a third party identifier,
such as email. It is passed the medium (eg. <code>email</code>), an address (eg. <code>jdoe@example.com</code>)
and the user's password.</p>
<p>If the authentication is successful, the module must return the user's Matrix ID (e.g. 
<code>@alice:example.com</code>) and optionally a callback to be called with the response to the <code>/login</code> request.
If the module doesn't wish to return a callback, it must return None instead.</p>
<p>If the authentication is unsuccessful, the module must return <code>None</code>.</p>
<p>If multiple modules implement this callback, they will be considered in order. If a
callback returns <code>None</code>, Synapse falls through to the next one. The value of the first
callback that does not return <code>None</code> will be used. If this happens, Synapse will not call
any of the subsequent implementations of this callback. If every callback returns <code>None</code>,
the authentication is denied.</p>
<h3 id="on_logged_out"><a class="header" href="#on_logged_out"><code>on_logged_out</code></a></h3>
<p><em>First introduced in Synapse v1.46.0</em></p>
<pre><code class="language-python">async def on_logged_out(
    user_id: str,
    device_id: Optional[str],
    access_token: str
) -&gt; None
</code></pre>
<p>Called during a logout request for a user. It is passed the qualified user ID, the ID of the
deactivated device (if any: access tokens are occasionally created without an associated
device ID), and the (now deactivated) access token.</p>
<p>If multiple modules implement this callback, Synapse runs them all in order.</p>
<h3 id="get_username_for_registration"><a class="header" href="#get_username_for_registration"><code>get_username_for_registration</code></a></h3>
<p><em>First introduced in Synapse v1.52.0</em></p>
<pre><code class="language-python">async def get_username_for_registration(
    uia_results: Dict[str, Any],
    params: Dict[str, Any],
) -&gt; Optional[str]
</code></pre>
<p>Called when registering a new user. The module can return a username to set for the user
being registered by returning it as a string, or <code>None</code> if it doesn't wish to force a
username for this user. If a username is returned, it will be used as the local part of a
user's full Matrix ID (e.g. it's <code>alice</code> in <code>@alice:example.com</code>).</p>
<p>This callback is called once <a href="https://spec.matrix.org/latest/client-server-api/#user-interactive-authentication-api">User-Interactive Authentication</a>
has been completed by the user. It is not called when registering a user via SSO. It is
passed two dictionaries, which include the information that the user has provided during
the registration process.</p>
<p>The first dictionary contains the results of the <a href="https://spec.matrix.org/latest/client-server-api/#user-interactive-authentication-api">User-Interactive Authentication</a>
flow followed by the user. Its keys are the identifiers of every step involved in the flow,
associated with either a boolean value indicating whether the step was correctly completed,
or additional information (e.g. email address, phone number...). A list of most existing
identifiers can be found in the <a href="https://spec.matrix.org/v1.1/client-server-api/#authentication-types">Matrix specification</a>.
Here's an example featuring all currently supported keys:</p>
<pre><code class="language-python">{
    &quot;m.login.dummy&quot;: True,  # Dummy authentication
    &quot;m.login.terms&quot;: True,  # User has accepted the terms of service for the homeserver
    &quot;m.login.recaptcha&quot;: True,  # User has completed the recaptcha challenge
    &quot;m.login.email.identity&quot;: {  # User has provided and verified an email address
        &quot;medium&quot;: &quot;email&quot;,
        &quot;address&quot;: &quot;alice@example.com&quot;,
        &quot;validated_at&quot;: 1642701357084,
    },
    &quot;m.login.msisdn&quot;: {  # User has provided and verified a phone number
        &quot;medium&quot;: &quot;msisdn&quot;,
        &quot;address&quot;: &quot;33123456789&quot;,
        &quot;validated_at&quot;: 1642701357084,
    },
    &quot;m.login.registration_token&quot;: &quot;sometoken&quot;,  # User has registered through a registration token
}
</code></pre>
<p>The second dictionary contains the parameters provided by the user's client in the request
to <code>/_matrix/client/v3/register</code>. See the <a href="https://spec.matrix.org/latest/client-server-api/#post_matrixclientv3register">Matrix specification</a>
for a complete list of these parameters.</p>
<p>If the module cannot, or does not wish to, generate a username for this user, it must
return <code>None</code>.</p>
<p>If multiple modules implement this callback, they will be considered in order. If a
callback returns <code>None</code>, Synapse falls through to the next one. The value of the first
callback that does not return <code>None</code> will be used. If this happens, Synapse will not call
any of the subsequent implementations of this callback. If every callback returns <code>None</code>,
the username provided by the user is used, if any (otherwise one is automatically
generated).</p>
<h3 id="get_displayname_for_registration"><a class="header" href="#get_displayname_for_registration"><code>get_displayname_for_registration</code></a></h3>
<p><em>First introduced in Synapse v1.54.0</em></p>
<pre><code class="language-python">async def get_displayname_for_registration(
    uia_results: Dict[str, Any],
    params: Dict[str, Any],
) -&gt; Optional[str]
</code></pre>
<p>Called when registering a new user. The module can return a display name to set for the
user being registered by returning it as a string, or <code>None</code> if it doesn't wish to force a
display name for this user.</p>
<p>This callback is called once <a href="https://spec.matrix.org/latest/client-server-api/#user-interactive-authentication-api">User-Interactive Authentication</a>
has been completed by the user. It is not called when registering a user via SSO. It is
passed two dictionaries, which include the information that the user has provided during
the registration process. These dictionaries are identical to the ones passed to
<a href="#get_username_for_registration"><code>get_username_for_registration</code></a>, so refer to the
documentation of this callback for more information about them.</p>
<p>If multiple modules implement this callback, they will be considered in order. If a
callback returns <code>None</code>, Synapse falls through to the next one. The value of the first
callback that does not return <code>None</code> will be used. If this happens, Synapse will not call
any of the subsequent implementations of this callback. If every callback returns <code>None</code>,
the username will be used (e.g. <code>alice</code> if the user being registered is <code>@alice:example.com</code>).</p>
<h2 id="is_3pid_allowed"><a class="header" href="#is_3pid_allowed"><code>is_3pid_allowed</code></a></h2>
<p><em>First introduced in Synapse v1.53.0</em></p>
<pre><code class="language-python">async def is_3pid_allowed(self, medium: str, address: str, registration: bool) -&gt; bool
</code></pre>
<p>Called when attempting to bind a third-party identifier (i.e. an email address or a phone
number). The module is given the medium of the third-party identifier (which is <code>email</code> if
the identifier is an email address, or <code>msisdn</code> if the identifier is a phone number) and
its address, as well as a boolean indicating whether the attempt to bind is happening as
part of registering a new user. The module must return a boolean indicating whether the
identifier can be allowed to be bound to an account on the local homeserver.</p>
<p>If multiple modules implement this callback, they will be considered in order. If a
callback returns <code>True</code>, Synapse falls through to the next one. The value of the first
callback that does not return <code>True</code> will be used. If this happens, Synapse will not call
any of the subsequent implementations of this callback.</p>
<h2 id="example"><a class="header" href="#example">Example</a></h2>
<p>The example module below implements authentication checkers for two different login types: </p>
<ul>
<li><code>my.login.type</code> 
<ul>
<li>Expects a <code>my_field</code> field to be sent to <code>/login</code></li>
<li>Is checked by the method: <code>self.check_my_login</code></li>
</ul>
</li>
<li><code>m.login.password</code> (defined in <a href="https://matrix.org/docs/spec/client_server/latest#password-based">the spec</a>)
<ul>
<li>Expects a <code>password</code> field to be sent to <code>/login</code></li>
<li>Is checked by the method: <code>self.check_pass</code></li>
</ul>
</li>
</ul>
<pre><code class="language-python">from typing import Awaitable, Callable, Optional, Tuple

import synapse
from synapse import module_api


class MyAuthProvider:
    def __init__(self, config: dict, api: module_api):

        self.api = api

        self.credentials = {
            &quot;bob&quot;: &quot;building&quot;,
            &quot;@scoop:matrix.org&quot;: &quot;digging&quot;,
        }

        api.register_password_auth_provider_callbacks(
            auth_checkers={
                (&quot;my.login_type&quot;, (&quot;my_field&quot;,)): self.check_my_login,
                (&quot;m.login.password&quot;, (&quot;password&quot;,)): self.check_pass,
            },
        )

    async def check_my_login(
        self,
        username: str,
        login_type: str,
        login_dict: &quot;synapse.module_api.JsonDict&quot;,
    ) -&gt; Optional[
        Tuple[
            str,
            Optional[Callable[[&quot;synapse.module_api.LoginResponse&quot;], Awaitable[None]]],
        ]
    ]:
        if login_type != &quot;my.login_type&quot;:
            return None

        if self.credentials.get(username) == login_dict.get(&quot;my_field&quot;):
            return self.api.get_qualified_user_id(username)

    async def check_pass(
        self,
        username: str,
        login_type: str,
        login_dict: &quot;synapse.module_api.JsonDict&quot;,
    ) -&gt; Optional[
        Tuple[
            str,
            Optional[Callable[[&quot;synapse.module_api.LoginResponse&quot;], Awaitable[None]]],
        ]
    ]:
        if login_type != &quot;m.login.password&quot;:
            return None

        if self.credentials.get(username) == login_dict.get(&quot;password&quot;):
            return self.api.get_qualified_user_id(username)
</code></pre>

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