From 28356a0c8bd79c989c469e710b3c6c1b90398dcf Mon Sep 17 00:00:00 2001
From: Dheerendra Rathor <dheeru.rathor14@gmail.com>
Date: Mon, 9 Oct 2017 03:36:54 +0530
Subject: [PATCH] Added subprotocol match on client

---
 README.md | 11 ++++++++++-
 main.go   | 17 +++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index b86071a..022ea1b 100644
--- a/README.md
+++ b/README.md
@@ -15,5 +15,14 @@ A simple websocket client in Golang to debug websocket server.
 
 ### Usages:
 ```bash
-.\SimpleWsClient --addr=wss://echo.websocket.org
+$ ./SimpleWsClient -help
+Usage of ./SimpleWsClient:
+  -addr string
+        http service address (default "ws://echo.websocket.org")
+  -echoDelay uint
+        Delay before echoing back received message from server
+  -protocols string
+        Comma separated list of protocols to use
+
+$ ./SimpleWsClient -addr wss://echo.websocket.org -protocols echo,chat
 ```
diff --git a/main.go b/main.go
index 8d500e6..09459eb 100644
--- a/main.go
+++ b/main.go
@@ -50,6 +50,23 @@ func main() {
 		log.Fatalf("Unable to dial ws connection to agent %s with error %s\n", address, err)
 	}
 
+	respSubProtocol := conn.Subprotocol()
+	subProtocolMatch := false
+	if len(dialer.Subprotocols) > 0 {
+		for _, val := range dialer.Subprotocols {
+			if val == respSubProtocol {
+				subProtocolMatch = true
+				break
+			}
+		}
+	} else {
+		subProtocolMatch = respSubProtocol == ""
+	}
+
+	if !subProtocolMatch {
+		log.Fatalf("Subprotocol match failed. Server returned subprotocol: '%s'\n", respSubProtocol)
+	}
+
 	log.Println("Connection stabilized")
 	defer conn.Close()