[v2] DevServer improvements and fixes (#2664)

* [assetserver, darwin] Fix copying request headers by using strdup

* [assetserver, linux] Fake some basic http headers for legacy webkit2 versions to support proxying requests to other servers

This fixes the devserver on v2 for newer vite versions that use the custom
scheme.

* [v2, windows] 304 responses are going to hang the WebView2 so prevent them by removing cache related headers in the request.

* [v2, dev] Now uses the custom schemes `wails://` on macOS and Linux for all Vite versions.

Prevent missing reload after fast multiple savings on Linux and Windows.

v2/pkg/assetserver/assetserver.go

@@ -32,7 +32,6 @@ type RuntimeHandler interface {
 
 type AssetServer struct {
 	handler   http.Handler
-	wsHandler http.Handler
 	runtimeJS []byte
 	ipcJS     func(*http.Request) []byte
 
@@ -107,12 +106,8 @@ func (d *AssetServer) AddPluginScript(pluginName string, script string) {
 
 func (d *AssetServer) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 	if isWebSocket(req) {
-		// Forward WebSockets to the distinct websocket handler if it exists
-		if wsHandler := d.wsHandler; wsHandler != nil {
-			wsHandler.ServeHTTP(rw, req)
-		} else {
-			rw.WriteHeader(http.StatusNotImplemented)
-		}
+		// WebSockets are not supported by the AssetServer
+		rw.WriteHeader(http.StatusNotImplemented)
 		return
 	}
 

v2/pkg/assetserver/assetserver_dev.go

@@ -13,13 +13,12 @@ The assetserver for the dev mode.
 Depending on the UserAgent it injects a websocket based IPC script into `index.html` or the default desktop IPC. The
 default desktop IPC is injected when the webview accesses the devserver.
 */
-func NewDevAssetServer(handler http.Handler, wsHandler http.Handler, bindingsJSON string, servingFromDisk bool, logger Logger, runtime RuntimeAssets) (*AssetServer, error) {
+func NewDevAssetServer(handler http.Handler, bindingsJSON string, servingFromDisk bool, logger Logger, runtime RuntimeAssets) (*AssetServer, error) {
 	result, err := NewAssetServerWithHandler(handler, bindingsJSON, servingFromDisk, logger, runtime)
 	if err != nil {
 		return nil, err
 	}
 
-	result.wsHandler = wsHandler
 	result.appendSpinnerToBody = true
 	result.ipcJS = func(req *http.Request) []byte {
 		if strings.Contains(req.UserAgent(), WailsUserAgentValue) {

v2/pkg/assetserver/webview/request_darwin.go

@@ -8,6 +8,7 @@ package webview
 
 #import <Foundation/Foundation.h>
 #import <WebKit/WebKit.h>
+#include <string.h>
 
 static void URLSchemeTaskRetain(void *wkUrlSchemeTask) {
 	id<WKURLSchemeTask> urlSchemeTask = (id<WKURLSchemeTask>) wkUrlSchemeTask;
@@ -44,9 +45,7 @@ static const char * URLSchemeTaskRequestHeadersJSON(void *wkUrlSchemeTask) {
 		NSString* headerString = [[[NSString alloc] initWithData:headerData encoding:NSUTF8StringEncoding] autorelease];
 		const char * headerJSON = [headerString UTF8String];
 
-		char * headersOut = malloc(strlen(headerJSON));
-		strcpy(headersOut, headerJSON);
-		return headersOut;
+		return strdup(headerJSON);
 	}
 }
 

v2/pkg/assetserver/webview/webkit2_legacy.go

@@ -24,7 +24,12 @@ func webkit_uri_scheme_request_get_http_method(_ *C.WebKitURISchemeRequest) stri
 }
 
 func webkit_uri_scheme_request_get_http_headers(_ *C.WebKitURISchemeRequest) http.Header {
-	return http.Header{}
+	// Fake some basic default headers that are needed if e.g. request are being proxied to the an external sever, like
+	// we do in the devserver.
+	h := http.Header{}
+	h.Add("Accept", "*/*")
+	h.Add("User-Agent", "wails.io/605.1.15")
+	return h
 }
 
 func webkit_uri_scheme_request_get_http_body(_ *C.WebKitURISchemeRequest) io.ReadCloser {