Question

我正在尝试使用Chrome打印到PDF来构建从HTML到PDF的转换器。选项。

我已经尝试过无头Chrome的命令行程序，但我无法添加任何设置，因此我现在尝试使用M asterDevs.ChromeDevTools。

我的问题是每次通过await时应用程序都进入breakmode，我真的不明白问题是什么。

using System;
using MasterDevs.ChromeDevTools.Protocol.Chrome.Page;
using System.IO;
using System.Linq;
using System.Threading;
using MasterDevs.ChromeDevTools.Protocol.Chrome.DOM;
using Task = System.Threading.Tasks.Task;
using MasterDevs.ChromeDevTools;

namespace ConsoleApp4
{
    internal class Program
    {
        const int ViewPortWidth = 1440;
        const int ViewPortHeight = 900;
        private static void Main(string[] args)
        {
            Task.Run(async () =>
            {


                // STEP 1 - Run Chrome
                var chromeProcessFactory = new ChromeProcessFactory(new StubbornDirectoryCleaner());
                using (var chromeProcess = chromeProcessFactory.Create(9222, true))
                {
                    // STEP 2 - Create a debugging session
                    var sessionInfo = (await chromeProcess.GetSessionInfo()).LastOrDefault();
                    var chromeSessionFactory = new ChromeSessionFactory();
                    var chromeSession = chromeSessionFactory.Create(sessionInfo.WebSocketDebuggerUrl);

                    // STEP 3 - Send a command
                    //
                    // Here we are sending a commands to tell chrome to set the viewport size 
                    // and navigate to the specified URL
                    //await chromeSession.SendAsync(new SetDeviceMetricsOverrideCommand
                    //{
                    //    Width = ViewPortWidth,
                    //    Height = ViewPortHeight,
                    //    Scale = 1
                    //});

                    var navigateResponse = await chromeSession.SendAsync(new NavigateCommand
                    {
                        Url = "http://www.google.com"
                    });
                    Console.WriteLine("NavigateResponse: " + navigateResponse.Id);

                    var printResponse = await chromeSession.SendAsync(new PrintToPDFCommand {
                        Landscape = true
                        , DisplayHeaderFooter = true
                        , MarginBottom = 0
                        , MarginTop = 0
                        , MarginRight = 0
                        , MarginLeft = 0
                    });

                    Console.WriteLine("NavigateResponse: " + navigateResponse.Id);

                    Console.WriteLine("Exiting ..");
                }
            }).Wait();
        }
    }
}

Answer 1

好吧，让我告诉你为什么：

您没有设置纸张尺寸或比例！

然后，“ MasterDev”无法正确处理Chrome返回的后续错误。

因此，任务永远不会设置为“错误”或“成功”。
这就是为什么此时C＃会无限期地等待答案的原因。

猜猜我怎么知道？
1.5年前，当我遇到相同问题时，我正在调试一个小时；）

这是错误修正提案的问题：
https://github.com/MasterDevs/ChromeDevTools/issues/37

Dim cm2inch As UnitConversion_t = Function(ByVal centimeters As Double) centimeters * 0.393701
Dim mm2inch As UnitConversion_t = Function(ByVal milimeters As Double) milimeters * 0.0393701

Dim printCommand2 As PrintToPDFCommand = New PrintToPDFCommand() With {
    .Scale = 1,
    .MarginTop = 0,
    .MarginLeft = 0,
    .MarginRight = 0,
    .MarginBottom = 0,
    .PrintBackground = True,
    .Landscape = False,
    .PaperWidth = mm2inch(conversionData.PageWidth),
    .PaperHeight = mm2inch(conversionData.PageHeight) ' 
}

另请参阅 How to receive the height of DOM element when printing with wkhtmltopdf library?

使用c＃ChromeDevTools应用程序上的无头镶边打印到pdf应用程序进入breakmode

1 个答案: