Add narFromPath op to nix daemon

src/libstore/worker-protocol.hh

@@ -46,6 +46,7 @@ typedef enum {
     wopVerifyStore = 35,
     wopBuildDerivation = 36,
     wopAddSignatures = 37,
+    wopNarFromPath = 38
 } WorkerOp;
 
 

src/nix-daemon/nix-daemon.cc

@@ -576,6 +576,14 @@ static void performOp(ref<LocalStore> store, bool trusted, unsigned int clientVe
         break;
     }
 
+    case wopNarFromPath: {
+        auto path = readStorePath(*store, from);
+        startWork();
+        dumpPath(path, to);
+        stopWork();
+        break;
+    }
+
     default:
         throw Error(format("invalid operation %1%") % op);
     }