Added UI for plugin system and upnp example

- Added wip UI for plugin tag system
- Added upnp port forwarder plugin
- Added error and fatal printout for plugins
- Optimized UI flow for plugin context window
- Added dev web server for plugin development purpose

example/plugins/debugger/mod/zoraxy_plugin/dev_webserver.go

@@ -0,0 +1,145 @@
+package zoraxy_plugin
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"strings"
+	"time"
+)
+
+type PluginUiDebugRouter struct {
+	PluginID         string //The ID of the plugin
+	TargetDir        string //The directory where the UI files are stored
+	HandlerPrefix    string //The prefix of the handler used to route this router, e.g. /ui
+	EnableDebug      bool   //Enable debug mode
+	terminateHandler func() //The handler to be called when the plugin is terminated
+}
+
+// NewPluginFileSystemUIRouter creates a new PluginUiRouter with file system
+// The targetDir is the directory where the UI files are stored (e.g. ./www)
+// 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 NewPluginFileSystemUIRouter(pluginID string, targetDir string, handlerPrefix string) *PluginUiDebugRouter {
+	//Make sure all prefix are in /prefix format
+	if !strings.HasPrefix(handlerPrefix, "/") {
+		handlerPrefix = "/" + handlerPrefix
+	}
+	handlerPrefix = strings.TrimSuffix(handlerPrefix, "/")
+
+	//Return the PluginUiRouter
+	return &PluginUiDebugRouter{
+		PluginID:      pluginID,
+		TargetDir:     targetDir,
+		HandlerPrefix: handlerPrefix,
+	}
+}
+
+func (p *PluginUiDebugRouter) 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, ".html") {
+			//Read the target file from file system
+			targetFilePath := strings.TrimPrefix(r.URL.Path, "/")
+			targetFilePath = p.TargetDir + "/" + targetFilePath
+			targetFilePath = strings.TrimPrefix(targetFilePath, "/")
+			targetFileContent, err := os.ReadFile(targetFilePath)
+			if err != nil {
+				http.Error(w, "File not found", http.StatusNotFound)
+				return
+			}
+			body := string(targetFileContent)
+			body = strings.ReplaceAll(body, "{{.csrfToken}}", csrfToken)
+			w.Header().Set("Content-Type", "text/html")
+			w.WriteHeader(http.StatusOK)
+			w.Write([]byte(body))
+			return
+		} else if strings.HasSuffix(r.URL.Path, "/") {
+			//Check if the request is for a directory
+			//Check if the directory has an index.html file
+			targetFilePath := strings.TrimPrefix(r.URL.Path, "/")
+			targetFilePath = p.TargetDir + "/" + targetFilePath + "index.html"
+			targetFilePath = strings.TrimPrefix(targetFilePath, "/")
+			if _, err := os.Stat(targetFilePath); err == nil {
+				//Serve the index.html file
+				targetFileContent, err := os.ReadFile(targetFilePath)
+				if err != nil {
+					http.Error(w, "File not found", http.StatusNotFound)
+					return
+				}
+				body := string(targetFileContent)
+				body = strings.ReplaceAll(body, "{{.csrfToken}}", csrfToken)
+				w.Header().Set("Content-Type", "text/html")
+				w.WriteHeader(http.StatusOK)
+				w.Write([]byte(body))
+				return
+			}
+		}
+
+		//Call the next handler
+		fsHandler.ServeHTTP(w, r)
+	})
+
+}
+
+// GetHttpHandler returns the http.Handler for the PluginUiRouter
+func (p *PluginUiDebugRouter) Handler() http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		//Remove the plugin UI handler path prefix
+		if p.EnableDebug {
+			fmt.Print("Request URL:", r.URL.Path, " rewriting to ")
+		}
+
+		rewrittenURL := r.RequestURI
+		rewrittenURL = strings.TrimPrefix(rewrittenURL, p.HandlerPrefix)
+		rewrittenURL = strings.ReplaceAll(rewrittenURL, "//", "/")
+		r.URL.Path = rewrittenURL
+		r.RequestURI = rewrittenURL
+		if p.EnableDebug {
+			fmt.Println(r.URL.Path)
+		}
+
+		//Serve the file from the file system
+		fsHandler := http.FileServer(http.Dir(p.TargetDir))
+
+		// Replace {{csrf_token}} with the actual CSRF token and serve the file
+		p.populateCSRFToken(r, fsHandler).ServeHTTP(w, r)
+	})
+}
+
+// RegisterTerminateHandler registers the terminate handler for the PluginUiRouter
+// The terminate handler will be called when the plugin is terminated from Zoraxy plugin manager
+// if mux is nil, the handler will be registered to http.DefaultServeMux
+func (p *PluginUiDebugRouter) RegisterTerminateHandler(termFunc func(), mux *http.ServeMux) {
+	p.terminateHandler = termFunc
+	if mux == nil {
+		mux = http.DefaultServeMux
+	}
+	mux.HandleFunc(p.HandlerPrefix+"/term", func(w http.ResponseWriter, r *http.Request) {
+		p.terminateHandler()
+		w.WriteHeader(http.StatusOK)
+		go func() {
+			//Make sure the response is sent before the plugin is terminated
+			time.Sleep(100 * time.Millisecond)
+			os.Exit(0)
+		}()
+	})
+}
+
+// Attach the file system UI handler to the target http.ServeMux
+func (p *PluginUiDebugRouter) AttachHandlerToMux(mux *http.ServeMux) {
+	if mux == nil {
+		mux = http.DefaultServeMux
+	}
+
+	p.HandlerPrefix = strings.TrimSuffix(p.HandlerPrefix, "/")
+	mux.Handle(p.HandlerPrefix+"/", p.Handler())
+}

example/plugins/debugger/mod/zoraxy_plugin/embed_webserver.go

@@ -74,6 +74,20 @@ func (p *PluginUiRouter) populateCSRFToken(r *http.Request, fsHandler http.Handl
 			w.WriteHeader(http.StatusOK)
 			w.Write([]byte(body))
 			return
+		} else if strings.HasSuffix(r.URL.Path, "/") {
+			// Check if the directory has an index.html file
+			indexFilePath := strings.TrimPrefix(r.URL.Path, "/") + "index.html"
+			indexFilePath = p.TargetFsPrefix + "/" + indexFilePath
+			indexFilePath = strings.TrimPrefix(indexFilePath, "/")
+			indexFileContent, err := fs.ReadFile(*p.TargetFs, indexFilePath)
+			if err == nil {
+				body := string(indexFileContent)
+				body = strings.ReplaceAll(body, "{{.csrfToken}}", csrfToken)
+				w.Header().Set("Content-Type", "text/html")
+				w.WriteHeader(http.StatusOK)
+				w.Write([]byte(body))
+				return
+			}
 		}
 
 		//Call the next handler
@@ -130,3 +144,13 @@ func (p *PluginUiRouter) RegisterTerminateHandler(termFunc func(), mux *http.Ser
 		}()
 	})
 }
+
+// Attach the embed UI handler to the target http.ServeMux
+func (p *PluginUiRouter) AttachHandlerToMux(mux *http.ServeMux) {
+	if mux == nil {
+		mux = http.DefaultServeMux
+	}
+
+	p.HandlerPrefix = strings.TrimSuffix(p.HandlerPrefix, "/")
+	mux.Handle(p.HandlerPrefix+"/", p.Handler())
+}