Added embed server for plugin library

- Added embeded resources server for plugin library
- Added ztnc plugin for global area network
- Added wide mode for side wrapper

example/plugins/helloworld/zoraxy_plugin/README.txt

@@ -0,0 +1,19 @@
+# Zoraxy Plugin
+
+## Overview
+This module serves as a template for building your own plugins for the Zoraxy Reverse Proxy. By copying this module to your plugin mod folder, you can create a new plugin with the necessary structure and components.
+
+## Instructions
+
+1. **Copy the Module:**
+    - Copy the entire `zoraxy_plugin` module to your plugin mod folder.
+
+2. **Include the Structure:**
+    - Ensure that you maintain the directory structure and file organization as provided in this module.
+
+3. **Modify as Needed:**
+    - Customize the copied module to implement the desired functionality for your plugin.
+
+## Directory Structure
+ zoraxy_plugin: Handle -introspect and -configuration process required for plugin loading and startup
+ embed_webserver: Handle embeded web server routing and injecting csrf token to your plugin served UI pages

example/plugins/helloworld/zoraxy_plugin/embed_webserver.go

@@ -0,0 +1,106 @@
+package zoraxy_plugin
+
+import (
+	"embed"
+	"fmt"
+	"io/fs"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+)
+
+type PluginUiRouter struct {
+	PluginID       string    //The ID of the plugin
+	TargetFs       *embed.FS //The embed.FS where the UI files are stored
+	TargetFsPrefix string    //The prefix of the embed.FS where the UI files are stored, e.g. /web
+	HandlerPrefix  string    //The prefix of the handler used to route this router, e.g. /ui
+}
+
+// NewPluginEmbedUIRouter creates a new PluginUiRouter with embed.FS
+// The targetFsPrefix is the prefix of the embed.FS where the UI files are stored
+// The targetFsPrefix should be relative to the root of the embed.FS
+// The targetFsPrefix should start with a slash (e.g. /web) that corresponds to the root folder of the embed.FS
+// The handlerPrefix is the prefix of the handler used to route this router
+// The handlerPrefix should start with a slash (e.g. /ui) that matches the http.Handle path
+// All prefix should not end with a slash
+func NewPluginEmbedUIRouter(pluginID string, targetFs *embed.FS, targetFsPrefix string, handlerPrefix string) *PluginUiRouter {
+	//Make sure all prefix are in /prefix format
+	if !strings.HasPrefix(targetFsPrefix, "/") {
+		targetFsPrefix = "/" + targetFsPrefix
+	}
+	targetFsPrefix = strings.TrimSuffix(targetFsPrefix, "/")
+
+	if !strings.HasPrefix(handlerPrefix, "/") {
+		handlerPrefix = "/" + handlerPrefix
+	}
+	handlerPrefix = strings.TrimSuffix(handlerPrefix, "/")
+
+	//Return the PluginUiRouter
+	return &PluginUiRouter{
+		PluginID:       pluginID,
+		TargetFs:       targetFs,
+		TargetFsPrefix: targetFsPrefix,
+		HandlerPrefix:  handlerPrefix,
+	}
+}
+
+func (p *PluginUiRouter) populateCSRFToken(r *http.Request, fsHandler http.Handler) http.Handler {
+	//Get the CSRF token from header
+	csrfToken := r.Header.Get("X-Zoraxy-Csrf")
+	if csrfToken == "" {
+		csrfToken = "missing-csrf-token"
+	}
+
+	//Return the middleware
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Check if the request is for an HTML file
+		if strings.HasSuffix(r.URL.Path, "/") {
+			// Redirect to the index.html
+			http.Redirect(w, r, r.URL.Path+"index.html", http.StatusFound)
+			return
+		}
+		if strings.HasSuffix(r.URL.Path, ".html") {
+			//Read the target file from embed.FS
+			targetFilePath := strings.TrimPrefix(r.URL.Path, "/")
+			targetFilePath = p.TargetFsPrefix + "/" + targetFilePath
+			targetFilePath = strings.TrimPrefix(targetFilePath, "/")
+			fmt.Println(targetFilePath)
+			targetFileContent, err := fs.ReadFile(*p.TargetFs, targetFilePath)
+			if err != nil {
+				http.Error(w, "File not found", http.StatusNotFound)
+				return
+			}
+			body := string(targetFileContent)
+			body = strings.ReplaceAll(body, "{{.csrfToken}}", csrfToken)
+			http.ServeContent(w, r, r.URL.Path, time.Now(), strings.NewReader(body))
+			return
+		}
+
+		//Call the next handler
+		fsHandler.ServeHTTP(w, r)
+	})
+
+}
+
+// GetHttpHandler returns the http.Handler for the PluginUiRouter
+func (p *PluginUiRouter) Handler() http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		//Remove the plugin UI handler path prefix
+		rewrittenURL := r.RequestURI
+		rewrittenURL = strings.TrimPrefix(rewrittenURL, p.HandlerPrefix)
+		rewrittenURL = strings.ReplaceAll(rewrittenURL, "//", "/")
+		r.URL, _ = url.Parse(rewrittenURL)
+		r.RequestURI = rewrittenURL
+		//Serve the file from the embed.FS
+		subFS, err := fs.Sub(*p.TargetFs, strings.TrimPrefix(p.TargetFsPrefix, "/"))
+		if err != nil {
+			fmt.Println(err.Error())
+			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+			return
+		}
+
+		// Replace {{csrf_token}} with the actual CSRF token and serve the file
+		p.populateCSRFToken(r, http.FileServer(http.FS(subFS))).ServeHTTP(w, r)
+	})
+}

example/plugins/helloworld/zoraxy_plugin/zoraxy_plugin.go

@@ -4,7 +4,9 @@ import (
 	"encoding/json"
 	"fmt"
 	"os"
+	"os/signal"
 	"strings"
+	"syscall"
 )
 
 /*
@@ -184,3 +186,25 @@ func ServeAndRecvSpec(pluginSpect *IntroSpect) (*ConfigureSpec, error) {
 	ServeIntroSpect(pluginSpect)
 	return RecvConfigureSpec()
 }
+
+/*
+
+Shutdown handler
+
+This function will register a shutdown handler for the plugin
+The shutdown callback will be called when the plugin is shutting down
+You can use this to clean up resources like closing database connections
+*/
+
+func RegisterShutdownHandler(shutdownCallback func()) {
+	// Set up a channel to receive OS signals
+	sigChan := make(chan os.Signal, 1)
+	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
+
+	// Start a goroutine to listen for signals
+	go func() {
+		<-sigChan
+		shutdownCallback()
+		os.Exit(0)
+	}()
+}