Add fader level set method to RPC remote interface (#3571)

* add RPC method setFaderLevel (not yet working)

* introduce function SetControllerInFaderLevel to be able to use controller in for RPC interface

* add example for jamulusclient/setFaderLevel

* add range check to RPC to be able to correctly inform the RPC user that the command he has send has a problem

* clean up (TODO is already solved)

* update RPC documentation

* fix clang-format issues

* fix check-json-rpc-docs

* avoid renaming of existing function implementation

* fix clang format issue

---------

Co-authored-by: Volker Fischer <corrados@users.noreply.github.com>

Author: corrados

docs/JSON-RPC.md

@@ -222,6 +222,24 @@ Results:
 | result | string | Always "ok". |
 
 
+### jamulusclient/setFaderLevel
+
+Sets the fader level. Example: {"id":1,"jsonrpc":"2.0","method":"jamulusclient/setFaderLevel","params":{"channelIndex": 0,"level":  50}}.
+
+Parameters:
+
+| Name | Type | Description |
+| --- | --- | --- |
+| params.channelIndex | number | The channel index of the fader to be set. |
+| params.level | number | The fader level in range 0..100. |
+
+Results:
+
+| Name | Type | Description |
+| --- | --- | --- |
+| result | string | Always "ok". |
+
+
 ### jamulusclient/setName
 
 Sets your name.

src/client.h

@@ -260,6 +260,8 @@ class CClient : public QObject
     void OnTimerRemoteChanGainOrPan();
     void StartTimerGainOrPan();
 
+    void SetControllerInFaderLevel ( int iChannelIdx, int iValue ) { OnControllerInFaderLevel ( iChannelIdx, iValue ); }
+
     void SetInputBoost ( const int iNewBoost ) { iInputBoost = iNewBoost; }
 
     void SetRemoteInfo() { Channel.SetRemoteInfo ( ChannelInfo ); }

src/clientrpc.cpp

@@ -326,6 +326,33 @@ CClientRpc::CClientRpc ( CClient* pClient, CRpcServer* pRpcServer, QObject* pare
 
         response["result"] = "ok";
     } );
+
+    /// @rpc_method jamulusclient/setFaderLevel
+    /// @brief Sets the fader level. Example: {"id":1,"jsonrpc":"2.0","method":"jamulusclient/setFaderLevel","params":{"channelIndex": 0,"level":
+    /// 50}}.
+    /// @param {number} params.channelIndex - The channel index of the fader to be set.
+    /// @param {number} params.level - The fader level in range 0..100.
+    /// @result {string} result - Always "ok".
+    pRpcServer->HandleMethod ( "jamulusclient/setFaderLevel", [=] ( const QJsonObject& params, QJsonObject& response ) {
+        auto jsonChannelIndex = params["channelIndex"];
+        if ( !jsonChannelIndex.isDouble() || ( jsonChannelIndex.toInt() < 0 ) || ( jsonChannelIndex.toInt() > MAX_NUM_CHANNELS ) )
+        {
+            response["error"] =
+                CRpcServer::CreateJsonRpcError ( CRpcServer::iErrInvalidParams, "Invalid params: channelIndex is not a number or out-of-range" );
+            return;
+        }
+
+        auto jsonLevel = params["level"];
+        if ( !jsonLevel.isDouble() || ( jsonLevel.toInt() < 0 ) || ( jsonLevel.toInt() > 100 ) )
+        {
+            response["error"] =
+                CRpcServer::CreateJsonRpcError ( CRpcServer::iErrInvalidParams, "Invalid params: level is not a number or out-of-range" );
+            return;
+        }
+
+        pClient->SetControllerInFaderLevel ( jsonChannelIndex.toInt(), jsonLevel.toInt() );
+        response["result"] = "ok";
+    } );
 }
 
 QJsonValue CClientRpc::SerializeSkillLevel ( ESkillLevel eSkillLevel )