added Robot API

Author: yisu

Diff for: api_callback_test.go

@@ -5,15 +5,15 @@ import (
 )
 
 func TestRegisterCallback(t *testing.T) {
-	err := c.UpdateCallback([]string{"user_modify_org"}, "hello", "1234567890123456789012345678901234567890aes", "https://myalert.info/dingtalk/callback/")
+	err := c.UpdateCallback([]string{"user_modify_org"}, "hello", "1234567890123456789012345678901234567890aes", "https://go.myalert.info/dingtalk/callback/")
 	if err != nil {
 		t.Error(err)
 	}
 	err = c.DeleteCallback()
 	if err != nil {
 		t.Error(err)
 	}
-	err = c.RegisterCallback([]string{"user_add_org"}, "hello", "1234567890123456789012345678901234567890aes", "https://myalert.info/dingtalk/callback/")
+	err = c.RegisterCallback([]string{"user_add_org"}, "hello", "1234567890123456789012345678901234567890aes", "https://go.myalert.info/dingtalk/callback/")
 	if err != nil {
 		t.Error(err)
 	}

Diff for: api_robot.go

@@ -0,0 +1,20 @@
+package godingtalk
+
+import (
+	"net/url"
+)
+
+//SendRobotTextMessage can send a text message to a group chat
+func (c *DingTalkClient) SendRobotTextMessage(accessToken string, msg string) error {
+	var data OAPIResponse
+    params := url.Values{}
+    params.Add("access_token", accessToken)	
+	request := map[string]interface{}{
+		"msgtype": "text",
+		"text": map[string]interface{}{
+			"content": msg,
+		},
+	}
+	err := c.httpRPC("robot/send", params, request, &data)
+	return err
+}

Diff for: godingtalk.go

@@ -29,7 +29,7 @@ type DingTalkClient struct {
 	//社交相关的属性
 	SnsAppID string
 	SnsAppSecret string
-	SnsAccessToken string
+	SnsAccessToken string	
 }
 
 //Unmarshallable is

Diff for: godingtalk_test.go

@@ -127,3 +127,11 @@ func TestVoiceMessage(t *testing.T) {
 		t.Error(err)
 	}
 }
+
+
+func TestRobotMessage(t *testing.T) {
+	err := c.SendRobotTextMessage("b7e4b04c66b5d53669affb0b92cf533b9eff9b2bc47f86ff9f4227a2ba73798e", "这是一条测试消息")
+	if err != nil {
+		t.Error(err)
+	}
+}

Diff for: transport.go

@@ -32,7 +32,9 @@ func (c *DingTalkClient) httpRPC(path string, params url.Values, requestData int
 		if params == nil {
 			params = url.Values{}
 		}
-		params.Set("access_token", c.AccessToken)
+		if (params.Get("access_token")=="") {
+			params.Set("access_token", c.AccessToken)
+		}
 	}
 	return c.httpRequest(path, params, requestData, responseData)
 }