Xilium CefGlue-如何同步获取HTML源代码？ [英] Xilium CefGlue - How to get HTML source synchonously?

问题描述

我想获取CEF3 / Xilium CefGlue rom非UI线程（屏幕外浏览器）中的网页来源

I want to get source of web page in CEF3/Xilium CefGlue rom non-UI thread (offscreen browser)

我这样做

internal class TestCefLoadHandler : CefLoadHandler
{
    protected override void OnLoadStart(CefBrowser browser, CefFrame frame)
    {
        // A single CefBrowser instance can handle multiple requests for a single URL if there are frames (i.e. <FRAME>, <IFRAME>).
        if (frame.IsMain)
        {
            Console.WriteLine("START: {0}", browser.GetMainFrame().Url);
        }
    }

    protected override void OnLoadEnd(CefBrowser browser, CefFrame frame, int httpStatusCode)
    {
        if (frame.IsMain)
        {
            MyCefStringVisitor mcsv = new MyCefStringVisitor();
            frame.GetSource(mcsv);

            Console.WriteLine("END: {0}, {1}", browser.GetMainFrame().Url, httpStatusCode);
        }
    }
}

class MyCefStringVisitor : CefStringVisitor
{
    private string html;

    protected override void Visit(string value)
    {
        html = value;
    }
    public string Html
    {
        get { return html; }
        set { html = value; }
    }
}

但调用

GetSource(...)

是异步的，因此在尝试对结果进行任何操作之前，我需要等待调用发生。

is asynchronous, so I need to wait for the call to occur before trying to do anything with result.

如何等待通话发生？

推荐答案

根据亚历克斯·梅特兰（Alex Maitland）的提示，我对我说，我可以适应 CefSharp 实现（ https://github.com/cefsharp/CefSharp/blob/master/CefSharp/TaskStringVisitor.cs ）来执行类似操作。

According to Alex Maitland tip that said to me that I can be able to adapt the CefSharp implementation (https://github.com/cefsharp/CefSharp/blob/master/CefSharp/TaskStringVisitor.cs) to do something similar.

我这样做：

    protected override async void OnLoadEnd(CefBrowser browser, CefFrame frame, int httpStatusCode)
    {
        if (frame.IsMain)
        {
            // MAIN CALL TAKES PLACE HERE
            string HTMLsource = await browser.GetSourceAsync();
            Console.WriteLine("END: {0}, {1}", browser.GetMainFrame().Url, httpStatusCode);
        }
    }


public class TaskStringVisitor : CefStringVisitor
{
    private readonly TaskCompletionSource<string> taskCompletionSource;

    public TaskStringVisitor()
    {
        taskCompletionSource = new TaskCompletionSource<string>();
    }

    protected override void Visit(string value)
    {
        taskCompletionSource.SetResult(value);
    }

    public Task<string> Task
    {
        get { return taskCompletionSource.Task; }
    }
}

public static class CEFExtensions
{
    public static Task<string> GetSourceAsync(this CefBrowser browser)
    {
        TaskStringVisitor taskStringVisitor = new TaskStringVisitor();
        browser.GetMainFrame().GetSource(taskStringVisitor);
        return taskStringVisitor.Task;
    }
}  

这篇关于Xilium CefGlue-如何同步获取HTML源代码？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！