Add config variables for enabling terms auth and the policy name (#4142)

So people can still collect consent the old way if they want to.

changelog.d/4004.feature

@@ -1 +1 @@
-Add `m.login.terms` to the registration flow when consent tracking is enabled. **This makes the template arguments conditionally optional on a new `public_version` variable - update your privacy templates to support this.**
+Include flags to optionally add `m.login.terms` to the registration flow when consent tracking is enabled.

changelog.d/4133.feature

@@ -1 +1 @@
-Add `m.login.terms` to the registration flow when consent tracking is enabled. **This makes the template arguments conditionally optional on a new `public_version` variable - update your privacy templates to support this.**
+Include flags to optionally add `m.login.terms` to the registration flow when consent tracking is enabled.

changelog.d/4142.feature

@@ -0,0 +1 @@
+Include flags to optionally add `m.login.terms` to the registration flow when consent tracking is enabled.

docs/consent_tracking.md

@@ -81,9 +81,40 @@ should be a matter of `pip install Jinja2`. On debian, try `apt-get install
 python-jinja2`.
 
 Once this is complete, and the server has been restarted, try visiting
-`https://<server>/_matrix/consent`. If correctly configured, you should see a
-default policy document. It is now possible to manually construct URIs where
-users can give their consent.
+`https://<server>/_matrix/consent`. If correctly configured, this should give
+an error "Missing string query parameter 'u'". It is now possible to manually
+construct URIs where users can give their consent.
+
+### Enabling consent tracking at registration
+
+1. Add the following to your configuration:
+
+   ```yaml
+   user_consent:
+     require_at_registration: true
+     policy_name: "Privacy Policy" # or whatever you'd like to call the policy
+   ```
+
+2. In your consent templates, make use of the `public_version` variable to
+   see if an unauthenticated user is viewing the page. This is typically
+   wrapped around the form that would be used to actually agree to the document:
+
+   ```
+   {% if not public_version %}
+     <!-- The variables used here are only provided when the 'u' param is given to the homeserver -->
+     <form method="post" action="consent">
+       <input type="hidden" name="v" value="{{version}}"/>
+       <input type="hidden" name="u" value="{{user}}"/>
+       <input type="hidden" name="h" value="{{userhmac}}"/>
+       <input type="submit" value="Sure thing!"/>
+     </form>
+   {% endif %}
+   ```
+
+3. Restart Synapse to apply the changes.
+
+Visiting `https://<server>/_matrix/consent` should now give you a view of the privacy
+document. This is what users will be able to see when registering for accounts.
 
 ### Constructing the consent URI
 
@@ -108,7 +139,8 @@ query parameters:
 
 Note that not providing a `u` parameter will be interpreted as wanting to view
 the document from an unauthenticated perspective, such as prior to registration.
-Therefore, the `h` parameter is not required in this scenario.
+Therefore, the `h` parameter is not required in this scenario. To enable this
+behaviour, set `require_at_registration` to `true` in your `user_consent` config.
 
 
 Sending users a server notice asking them to agree to the policy

synapse/config/consent_config.py

@@ -42,6 +42,14 @@ DEFAULT_CONFIG = """\
 # until the user consents to the privacy policy. The value of the setting is
 # used as the text of the error.
 #
+# 'require_at_registration', if enabled, will add a step to the registration
+# process, similar to how captcha works. Users will be required to accept the
+# policy before their account is created.
+#
+# 'policy_name' is the display name of the policy users will see when registering
+# for an account. Has no effect unless `require_at_registration` is enabled.
+# Defaults to "Privacy Policy".
+#
 # user_consent:
 #   template_dir: res/templates/privacy
 #   version: 1.0
@@ -54,6 +62,8 @@ DEFAULT_CONFIG = """\
 #   block_events_error: >-
 #     To continue using this homeserver you must review and agree to the
 #     terms and conditions at %(consent_uri)s
+#   require_at_registration: False
+#   policy_name: Privacy Policy
 #
 """
 
@@ -67,6 +77,8 @@ class ConsentConfig(Config):
         self.user_consent_server_notice_content = None
         self.user_consent_server_notice_to_guests = False
         self.block_events_without_consent_error = None
+        self.user_consent_at_registration = False
+        self.user_consent_policy_name = "Privacy Policy"
 
     def read_config(self, config):
         consent_config = config.get("user_consent")
@@ -83,6 +95,12 @@ class ConsentConfig(Config):
         self.user_consent_server_notice_to_guests = bool(consent_config.get(
             "send_server_notice_to_guests", False,
         ))
+        self.user_consent_at_registration = bool(consent_config.get(
+            "require_at_registration", False,
+        ))
+        self.user_consent_policy_name = consent_config.get(
+            "policy_name", "Privacy Policy",
+        )
 
     def default_config(self, **kwargs):
         return DEFAULT_CONFIG

synapse/handlers/auth.py

@@ -472,7 +472,7 @@ class AuthHandler(BaseHandler):
                 "privacy_policy": {
                     "version": self.hs.config.user_consent_version,
                     "en": {
-                        "name": "Privacy Policy",
+                        "name": self.hs.config.user_consent_policy_name,
                         "url": "%s/_matrix/consent?v=%s" % (
                             self.hs.config.public_baseurl,
                             self.hs.config.user_consent_version,

synapse/rest/client/v2_alpha/register.py

@@ -360,7 +360,7 @@ class RegisterRestServlet(RestServlet):
                 ])
 
         # Append m.login.terms to all flows if we're requiring consent
-        if self.hs.config.block_events_without_consent_error is not None:
+        if self.hs.config.user_consent_at_registration:
             new_flows = []
             for flow in flows:
                 flow.append(LoginType.TERMS)

synapse/rest/consent/consent_resource.py

@@ -142,7 +142,7 @@ class ConsentResource(Resource):
         userhmac = None
         has_consented = False
         public_version = username == ""
-        if not public_version:
+        if not public_version or not self.hs.config.user_consent_at_registration:
             userhmac = parse_string(request, "h", required=True, encoding=None)
 
             self._check_hash(username, userhmac)

tests/test_terms_auth.py

@@ -42,7 +42,8 @@ class TermsTestCase(unittest.HomeserverTestCase):
         hs.config.enable_registration_captcha = False
 
     def test_ui_auth(self):
-        self.hs.config.block_events_without_consent_error = True
+        self.hs.config.user_consent_at_registration = True
+        self.hs.config.user_consent_policy_name = "My Cool Privacy Policy"
         self.hs.config.public_baseurl = "https://example.org"
         self.hs.config.user_consent_version = "1.0"
 
@@ -66,7 +67,7 @@ class TermsTestCase(unittest.HomeserverTestCase):
                 "policies": {
                     "privacy_policy": {
                         "en": {
-                            "name": "Privacy Policy",
+                            "name": "My Cool Privacy Policy",
                             "url": "https://example.org/_matrix/consent?v=1.0",
                         },
                         "version": "1.0"

tests/utils.py

@@ -123,6 +123,8 @@ def default_config(name):
     config.user_directory_search_all_users = False
     config.user_consent_server_notice_content = None
     config.block_events_without_consent_error = None
+    config.user_consent_at_registration = False
+    config.user_consent_policy_name = "Privacy Policy"
     config.media_storage_providers = []
     config.autocreate_auto_join_rooms = True
     config.auto_join_rooms = []