docs/CHANGELOG.md

@@ -32,6 +32,8 @@ Matrix clients. (#35)
 - Moved all administrator API endpoints to `/_telodendria/admin/v1`, because later revisions
 of the administrator API may break clients, so we want a way to give those breaking revisions
 new endpoints.
+- Added a **PUT** option to `/_telodendria/admin/v1/config` that gives the ability to change
+only a subset of the configuration.
 - Implemented `/_telodendria/admin/v1/deactivate/[localpart]` for admins to be able to 
 deactivate users.
 - Implemented the following APIs for managing registration tokens:

docs/user/admin/config.md

@@ -4,7 +4,7 @@ As mentioned in [Setup](../setup.md), Telodendria's configuration is
 intended to be managed via the configuration API. Consult the
 [Configuration](../config.md) document for a complete list of supported
 configuration options. This document simply describes the API used to
-update the configuration.
+update the configuration described in that document.
 
 ## API Endpoints
 
@@ -40,3 +40,23 @@ configuration with the new one.
 |-------|------|-------------|
 | `restart_required` | `Boolean` | Whether or not the process needs to be restarted to finish applying the configuration. If this is `true`, then the restart endpoint should be used at a convenient time to apply the configuration.
 
+### **PUT** `/_telodendria/admin/config`
+
+Update the currently installed configuration instead of completely replacing it. This endpoint
+validates the request body, merges it on top of the current configuration, validates the resulting
+configuration, then updates it in the database. This is useful when only one or two properties
+in the configuration needs to be changed.
+
+| Requires Token | Rate Limited |
+|----------------|--------------|
+| Yes            | Yes          |
+
+| Response Code | Description |
+|---------------|-------------|
+| 200           | The new configuration was successfully installed.|
+
+#### 200 Response Format
+
+| Field | Type | Description |
+|-------|------|-------------|
+| `restart_required` | `Boolean` | Whether or not the process needs to be restarted to finish applying the configuration. If this is `true`, then the restart endpoint should be used at a convenient time to apply the configuration.

src/Main.c

@@ -128,10 +128,6 @@ start:
     httpServers = NULL;
     restart = 0;
 
-    /* For getopt() */
-    opterr = 1;
-    optind = 1;
-
     /* Local variables */
     exit = EXIT_SUCCESS;
     flags = 0;

src/Routes/RouteConfig.c

@@ -39,6 +39,7 @@ ROUTE_IMPL(RouteConfig, path, argp)
 
     HashMap *request = NULL;
     Config *newConf;
+    HashMap *newJson = NULL;
 
     (void) path;
 
@@ -121,10 +122,56 @@ ROUTE_IMPL(RouteConfig, path, argp)
             JsonFree(request);
             break;
         case HTTP_PUT:
-            /* TODO: Support incremental changes to the config */
+            request = JsonDecode(HttpServerStream(args->context));
+            if (!request)
+            {
+                HttpResponseStatus(args->context, HTTP_BAD_REQUEST);
+                response = MatrixErrorCreate(M_NOT_JSON, NULL);
+                break;
+            }
+
+            newJson = JsonDuplicate(DbJson(config->ref));
+            JsonMerge(newJson, request);
+
+            newConf = ConfigParse(newJson);
+
+            if (!newConf)
+            {
+                HttpResponseStatus(args->context, HTTP_INTERNAL_SERVER_ERROR);
+                response = MatrixErrorCreate(M_UNKNOWN, NULL);
+                break;
+            }
+
+            if (newConf->ok)
+            {
+                if (DbJsonSet(config->ref, newJson))
+                {
+                    response = HashMapCreate();
+                    /*
+                     * TODO: Apply configuration and set this only if a main
+                     * component was reconfigured, such as the listeners.
+                     */
+                    HashMapSet(response, "restart_required", JsonValueBoolean(1));
+                }
+                else
+                {
+                    HttpResponseStatus(args->context, HTTP_INTERNAL_SERVER_ERROR);
+                    response = MatrixErrorCreate(M_UNKNOWN, NULL);
+                }
+            }
+            else
+            {
+                HttpResponseStatus(args->context, HTTP_BAD_REQUEST);
+                response = MatrixErrorCreate(M_BAD_JSON, newConf->err);
+            }
+
+            ConfigFree(newConf);
+            JsonFree(request);
+            JsonFree(newJson);
+            break;
         default:
             HttpResponseStatus(args->context, HTTP_BAD_REQUEST);
-            response = MatrixErrorCreate(M_UNRECOGNIZED, NULL);
+            response = MatrixErrorCreate(M_UNRECOGNIZED, "Unknown request method.");
             break;
     }