有没有办法在 Windows WebView2 组件中进行自定义资源加载？ 例如，像自定义 URL 方案？

Question

I'm looking into using the WebView2 component for rendering some UI things on Windows, and I have a question about resource loading: for loading "normal" resources (ie HTML, CSS, images, JavaScript, whatever), the component mostly takes care of handling the loading of those resources itself. But I wonder if there is a way to hook into that loading process and control it yourself with WebView2?

As an example: say you want to load an image that is procedurally generated on native side of the WebView2, ie it is not in a file or on a server. How would you do that? Another example would be if you stored all your resources in a zip file or a SQLite database or something like that, and you wanted the WebView2 component to load resources directly from it (with you writing the "bridge" code yourself), how would you do that?

The reason I'm asking is because on macOS, WKWebView provides exactly this functionality by allowing you to create custom url schemes and hooking up handlers to them . This is exactly what I want, and it allows you to do something like this in your HTML:

<script type="text/javascript" src="my-scheme://test.js"/>

And on the Objective-C side, you can do a thing like this (leaving out boilerplate for hooking up my-scheme to this handler, this is the meat of the code for handling the response):

        const char* data = "function testFunction() { return 18; }";

        [task didReceiveResponse: [[NSURLResponse alloc]
                                   initWithURL: task.request.URL
                                   MIMEType: @"text/javascript"
                                   expectedContentLength: strlen(data)
                                   textEncodingName: @"ASCII"]];
        
        [task didReceiveData: [NSData
                               dataWithBytes: data
                               length:strlen(data)]];
        
        [task didFinish];

Ie by registering the custom url scheme handler, I could send over my C string there as a JavaScript file. It doesn't have to be a hard-coded C string, obviously, as I mentioned the most relevant uses for me would be to provide procedurally generated resources, as well as loading things that are not necessarily stored as files (or on a web server). How would you do this with WebView2?

Answer 1

One way I have sent any type of file from native code to a browser is by converting the file to Base64 and then sending it to the browser. In the case of WebView2 you could use ExecuteScriptAsync . Once the Base64 string is received you could have javascript code (which you have previously injected) to convert it into a blob/file and then you can add it to any part of the DOM you want.