support disabling/enabling users by http api

ref/api.md

@@ -869,7 +869,7 @@ Expects a JSON object:
 
 *   `csrf`: a CSRF token, required when using session authentication.
 *   `update`: `UserSubset`, sets the provided fields. Field-specific notes:
-    *   `username`: requires `adminUsers` permission.
+    *   `disabled`: requires `adminUsers` permission.
     *   `password`: when updating the password, the previous password must
         be supplied as a precondition, unless the caller has `adminUsers`
         permission.
@@ -877,6 +877,7 @@ Expects a JSON object:
         user's permissions currently neither adds nor limits permissions of
         existing sessions; it only changes what is available to newly created
         sessions.
+    *   `username`: requires `adminUsers` permission.
 *   `precondition`: `UserSubset`, forces the request to fail with HTTP status
     412 (Precondition failed) if the provided fields don't have the given
     values.
@@ -899,9 +900,7 @@ Returns HTTP status 204 (No Content) on success.
 
 A JSON object with any of the following parameters:
 
-*   `username`
-*   `preferences`, a JSON object which the server stores without interpreting.
-    This field is meant for user-level preferences meaningful to the UI.
+*   `disabled`, boolean indicating if all logins from the user are rejected.
 *   `password`
     *   on retrieval, a placeholder string to indicate a password is set,
         or null.
@@ -910,6 +909,9 @@ A JSON object with any of the following parameters:
     *   in updates, may be left absent to keep as-is, set to null to disable
         session creation, or set to a plaintext string.
 *   `permissions`, a `Permissions` as described below.
+*   `preferences`, a JSON object which the server stores without interpreting.
+    This field is meant for user-level preferences meaningful to the UI.
+*   `username`
 
 ### Permissions
 

server/src/json.rs

@@ -552,6 +552,8 @@ pub struct UserSubset<'a> {
     #[serde(borrow)]
     pub username: Option<&'a str>,
 
+    pub disabled: Option<bool>,
+
     pub preferences: Option<db::json::UserPreferences>,
 
     /// An optional password value.
@@ -568,6 +570,7 @@ impl<'a> From<&'a db::User> for UserSubset<'a> {
     fn from(u: &'a db::User) -> Self {
         Self {
             username: Some(&u.username),
+            disabled: Some(u.config.disabled),
             preferences: Some(u.config.preferences.clone()),
             password: Some(u.has_password().then_some("(censored)")),
             permissions: Some(u.permissions.clone().into()),

server/src/web/users.rs

@@ -143,6 +143,9 @@ impl Service {
         }
         require_csrf_if_session(&caller, r.csrf)?;
         if let Some(mut precondition) = r.precondition {
+            if matches!(precondition.disabled.take(), Some(d) if d != user.config.disabled) {
+                bail_t!(FailedPrecondition, "disabled mismatch");
+            }
             if matches!(precondition.username.take(), Some(n) if n != user.username) {
                 bail_t!(FailedPrecondition, "username mismatch");
             }
@@ -187,6 +190,9 @@ impl Service {
             if update != Default::default() && !caller.permissions.admin_users {
                 bail_t!(Unauthenticated, "must have admin_users permission");
             }
+            if let Some(d) = update.disabled.take() {
+                change.config.disabled = d;
+            }
             if let Some(n) = update.username.take() {
                 change.username = n.to_string();
             }