如何使用 Selenium Webdriver 和 C# 保存图像？

Question

I need to save an image on a website using Selenium Webdriver in a C# application, however I am not able to do this. So far the options I found do not work.
Please any solution?
Thanks.
One of the options I tested is using the gravity.code extension

using System.IO;
using OpenQA.Selenium;
using OpenQA.Selenium.Chrome;
using OpenQA.Selenium.Extensions;

driver = new ChromeDriver(driverService, opts);
          driver.Navigate().GoToUrl("https://rd1.com.br/fora-da-globo-fausto-silva-recusa-convite-do-canal-para-homenagem/");

          try
          {
             string ImageLink = "//*[@id='post-1163172']/div[8]/ul/li[2]/div[1]/a/img";
             // from element attribute
             var element = driver.FindElement(By.XPath(ImageLink)).DownloadResource(path: @"C:\temp\a.png", attribute: "src");

             // from element text
             var element2 = driver.FindElement(By.XPath(ImageLink)).DownloadResource(path: @"C:\temp\b.png");
          }
          catch (Exception ex)
          {
             Console.WriteLine(ex.Message);
          }

Answer 1

One way is to use WebClient from the System.Net namespace:

string ImageLink = "//*[@id='post-1163172']/div[8]/ul/li[2]/div[1]/a/img";

// Find the image element using xpath or other selector
var element = driver.FindElement(By.XPath(ImageLink));

// Get the value of the src attribute from the image element
var imageSrc = element.GetAttribute("src");

// Download the image file from the src URI
using (var client = new System.Net.WebClient())
{
    client.DownloadFile(imageSrc, @"C:\temp\a.png");
}

This can be simplified a bit by adding using System.Net; at the top of the file and, if using C# 8 or greater, omitting the braces for the using (var client = new WebClient()) block.

Update

To preserve session from WebDriver to read the image data into a data URL (base 64 representation) and write to a local file. Note that this will lose any exif/metadata in the image as it only reads the visual data.

This example uses the System.Drawing.Common NuGet package to pull in Bitmap and ImageFormat , but the same can be accomplished similarly with your library of choice.

string ImageLink = "//*[@id='post-1163172']/div[8]/ul/li[2]/div[1]/a/img";

// Create dataurl base64 string
var dataUrl = driver.ExecuteScript(@$"
    var c = document.createElement('canvas');
    var ctx = c.getContext('2d');
    var img = document.evaluate(""{ImageLink}"", document, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue;
    c.height=img.naturalHeight;
    c.width=img.naturalWidth;
    ctx.drawImage(img, 0, 0,img.naturalWidth, img.naturalHeight);
    var base64String = c.toDataURL();
    return base64String;
    ") as string;

// Write the image data out to a file
var base64 = dataUrl.Split(',').Last();
using var stream = new MemoryStream(Convert.FromBase64String(base64));
using var bitmap = new Bitmap(stream);
bitmap.Save(@"C:\temp\a.png", ImageFormat.Png);