[REST] give an appropriate response in warmup phase

Author: jonasschnelli

src/rest.cpp

@@ -188,6 +188,10 @@ bool HTTPReq_REST(AcceptedConnection *conn,
                   bool fRun)
 {
     try {
+        std::string statusmessage;
+        if(RPCIsInWarmup(&statusmessage))
+            throw RESTERR(HTTP_SERVICE_UNAVAILABLE, "Service temporarily unavailable: "+statusmessage);
+        
         for (unsigned int i = 0; i < ARRAYLEN(uri_prefixes); i++) {
             unsigned int plen = strlen(uri_prefixes[i].prefix);
             if (strURI.substr(0, plen) == uri_prefixes[i].prefix) {

src/rpcprotocol.h

@@ -28,6 +28,7 @@ enum HTTPStatusCode
     HTTP_FORBIDDEN             = 403,
     HTTP_NOT_FOUND             = 404,
     HTTP_INTERNAL_SERVER_ERROR = 500,
+    HTTP_SERVICE_UNAVAILABLE   = 503,
 };
 
 //! Bitcoin RPC error codes

src/rpcserver.cpp

@@ -756,6 +756,14 @@ void SetRPCWarmupFinished()
     fRPCInWarmup = false;
 }
 
+bool RPCIsInWarmup(std::string *outStatus)
+{
+    LOCK(cs_rpcWarmup);
+    if (outStatus)
+        *outStatus = rpcWarmupStatus;
+    return fRPCInWarmup;
+}
+
 void RPCRunHandler(const boost::system::error_code& err, boost::function<void(void)> func)
 {
     if (!err)

src/rpcserver.h

@@ -53,6 +53,9 @@ void SetRPCWarmupStatus(const std::string& newStatus);
 /* Mark warmup as done.  RPC calls will be processed from now on.  */
 void SetRPCWarmupFinished();
 
+/* returns the current warmup state.  */
+bool RPCIsInWarmup(std::string *statusOut);
+
 /**
  * Type-check arguments; throws JSONRPCError if wrong type given. Does not check that
  * the right number of arguments are passed, just that any passed are the correct type.