From c88a119259c8625b015db4cf8ea08e30ca16cc81 Mon Sep 17 00:00:00 2001
From: "Olivier Wilkinson (reivilibre)" <olivier@librepush.net>
Date: Tue, 27 Aug 2019 13:12:27 +0100
Subject: [PATCH 1/2] Add GET method to admin API /users/@user:dom/admin

Signed-off-by: Olivier Wilkinson (reivilibre) <olivier@librepush.net>
---
 changelog.d/5914.feature       |  1 +
 synapse/handlers/admin.py      |  9 ++++++++
 synapse/rest/admin/__init__.py |  2 +-
 synapse/rest/admin/users.py    | 40 +++++++++++++++++++++++++++-------
 4 files changed, 43 insertions(+), 9 deletions(-)
 create mode 100644 changelog.d/5914.feature

diff --git a/changelog.d/5914.feature b/changelog.d/5914.feature
new file mode 100644
index 0000000000..85c7bf5963
--- /dev/null
+++ b/changelog.d/5914.feature
@@ -0,0 +1 @@
+Add admin API endpoint for getting whether or not a user is a server administrator.
diff --git a/synapse/handlers/admin.py b/synapse/handlers/admin.py
index d30a68b650..1a87b58838 100644
--- a/synapse/handlers/admin.py
+++ b/synapse/handlers/admin.py
@@ -94,6 +94,15 @@ class AdminHandler(BaseHandler):
 
         return ret
 
+    def get_user_server_admin(self, user):
+        """
+        Get the admin bit on a user.
+
+        Args:
+            user_id (UserID): the (necessarily local) user to manipulate
+        """
+        return self.store.is_server_admin(user)
+
     def set_user_server_admin(self, user, admin):
         """
         Set the admin bit on a user.
diff --git a/synapse/rest/admin/__init__.py b/synapse/rest/admin/__init__.py
index 9ab1c2c9e0..fa91cc8dee 100644
--- a/synapse/rest/admin/__init__.py
+++ b/synapse/rest/admin/__init__.py
@@ -52,7 +52,7 @@ logger = logging.getLogger(__name__)
 
 
 class UsersRestServlet(RestServlet):
-    PATTERNS = historical_admin_path_patterns("/users/(?P<user_id>[^/]*)")
+    PATTERNS = historical_admin_path_patterns("/users/(?P<user_id>[^/]*)$")
 
     def __init__(self, hs):
         self.hs = hs
diff --git a/synapse/rest/admin/users.py b/synapse/rest/admin/users.py
index b0fddb6898..5364117420 100644
--- a/synapse/rest/admin/users.py
+++ b/synapse/rest/admin/users.py
@@ -22,24 +22,34 @@ from synapse.http.servlet import (
     assert_params_in_dict,
     parse_json_object_from_request,
 )
-from synapse.rest.admin import assert_requester_is_admin
+from synapse.rest.admin import assert_requester_is_admin, assert_user_is_admin
 from synapse.types import UserID
 
 
 class UserAdminServlet(RestServlet):
     """
-    Set whether or not a user is a server administrator.
+    Get or set whether or not a user is a server administrator.
 
     Note that only local users can be server administrators, and that an
     administrator may not demote themselves.
 
     Only server administrators can use this API.
 
-    Example:
-        PUT /_synapse/admin/v1/users/@reivilibre:librepush.net/admin
-        {
-            "admin": true
-        }
+    Examples:
+        * Get
+            GET /_synapse/admin/v1/users/@nonadmin:example.com/admin
+            response on success:
+                {
+                    "admin": false
+                }
+        * Set
+            PUT /_synapse/admin/v1/users/@reivilibre:librepush.net/admin
+            request body:
+                {
+                    "admin": true
+                }
+            response on success:
+                {}
     """
 
     PATTERNS = (re.compile("^/_synapse/admin/v1/users/(?P<user_id>@[^/]*)/admin$"),)
@@ -50,9 +60,23 @@ class UserAdminServlet(RestServlet):
         self.handlers = hs.get_handlers()
 
     @defer.inlineCallbacks
-    def on_PUT(self, request, user_id):
+    def on_GET(self, request, user_id):
         yield assert_requester_is_admin(self.auth, request)
+
+        target_user = UserID.from_string(user_id)
+
+        if not self.hs.is_mine(target_user):
+            raise SynapseError(400, "Only local users can be admins of this homeserver")
+
+        is_admin = yield self.handlers.admin_handler.get_user_server_admin(target_user)
+        is_admin = bool(is_admin)
+
+        return (200, {"admin": is_admin})
+
+    @defer.inlineCallbacks
+    def on_PUT(self, request, user_id):
         requester = yield self.auth.get_user_by_req(request)
+        yield assert_user_is_admin(self.auth, requester.user)
         auth_user = requester.user
 
         target_user = UserID.from_string(user_id)

From 1b959b6977249c1db198beb6e04e02fa667ebfab Mon Sep 17 00:00:00 2001
From: "Olivier Wilkinson (reivilibre)" <olivier@librepush.net>
Date: Tue, 27 Aug 2019 13:19:19 +0100
Subject: [PATCH 2/2] Document GET method for retrieving admin bit of user in
 admin API

Signed-off-by: Olivier Wilkinson (reivilibre) <olivier@librepush.net>
---
 docs/admin_api/user_admin_api.rst | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/docs/admin_api/user_admin_api.rst b/docs/admin_api/user_admin_api.rst
index 6ee5080eed..d0871f9438 100644
--- a/docs/admin_api/user_admin_api.rst
+++ b/docs/admin_api/user_admin_api.rst
@@ -86,6 +86,25 @@ with a body of:
 including an ``access_token`` of a server admin.
 
 
+Get whether a user is a server administrator or not
+===================================================
+
+
+The api is::
+
+    GET /_synapse/admin/v1/users/<user_id>/admin
+
+including an ``access_token`` of a server admin.
+
+A response body like the following is returned:
+
+.. code:: json
+
+    {
+        "admin": true
+    }
+
+
 Change whether a user is a server administrator or not
 ======================================================