server plugin: set version and op in http request query (#1707)

doc/server_plugin.md

@@ -22,7 +22,7 @@ HTTP path can be configured for each manage plugin in frps. We'll assume for thi
 A request to the RPC server will look like:
 
 ```
-POST /handler
+POST /handler?version=0.1.0&op=Login
 {
     "version": "0.1.0",
     "op": "Login",

models/plugin/server/http.go

@@ -21,6 +21,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"net/http"
+	"net/url"
 	"reflect"
 )
 
@@ -78,7 +79,10 @@ func (p *httpPlugin) do(ctx context.Context, r *Request, res *Response) error {
 	if err != nil {
 		return err
 	}
-	req, err := http.NewRequest("POST", p.url, bytes.NewReader(buf))
+	v := url.Values{}
+	v.Set("version", r.Version)
+	v.Set("op", r.Op)
+	req, err := http.NewRequest("POST", p.url+"?"+v.Encode(), bytes.NewReader(buf))
 	if err != nil {
 		return err
 	}

models/plugin/server/manager.go

@@ -55,6 +55,10 @@ func (m *Manager) Register(p Plugin) {
 }
 
 func (m *Manager) Login(content *LoginContent) (*LoginContent, error) {
+	if len(m.loginPlugins) == 0 {
+		return content, nil
+	}
+
 	var (
 		res = &Response{
 			Reject:   false,
@@ -85,6 +89,10 @@ func (m *Manager) Login(content *LoginContent) (*LoginContent, error) {
 }
 
 func (m *Manager) NewProxy(content *NewProxyContent) (*NewProxyContent, error) {
+	if len(m.newProxyPlugins) == 0 {
+		return content, nil
+	}
+
 	var (
 		res = &Response{
 			Reject:   false,
@@ -115,6 +123,10 @@ func (m *Manager) NewProxy(content *NewProxyContent) (*NewProxyContent, error) {
 }
 
 func (m *Manager) Ping(content *PingContent) (*PingContent, error) {
+	if len(m.pingPlugins) == 0 {
+		return content, nil
+	}
+
 	var (
 		res = &Response{
 			Reject:   false,
@@ -145,6 +157,10 @@ func (m *Manager) Ping(content *PingContent) (*PingContent, error) {
 }
 
 func (m *Manager) NewWorkConn(content *NewWorkConnContent) (*NewWorkConnContent, error) {
+	if len(m.newWorkConnPlugins) == 0 {
+		return content, nil
+	}
+
 	var (
 		res = &Response{
 			Reject:   false,