SVG从链接下载到文件失败，因为无效的base64？

Question

因此，我正在尝试下载看起来像base64但失败的SVG图像。 该URL的长度比此长度长很多，但为方便起见，我将其缩短了。

数据：image / svg + xml; utf8，％3C％3Fxml％20version％3D％221.0％22％20encoding％3D％22UTF-8％22％20standalone％3D％22no％22％3F％3E％0A％3Csvg％20xmlns ％3Axlink％3D％22http％3A％2F％2Fwww.w3.org％2F1999％2Fxlink％22％20height％3D％2232％22％20version％3D％221.1％22％20viewBox％3D％220％200％20320％20320 ％22％20wid3A％20％20％3Crect％20height％3D％22320％22％20id％3D％22rect％22％20rx％3D％2251.2％22％20width％3D％22320％22％20x％3D％220％22 ％20y％3D％220％22％2F％3E％0A％20％20％20％20％3CclipPath％20id％3D％22clip％22％3E％0A％20％20％20％20％20％20％20％3Cuse ％20xlink％3Ahref％3D％22％23rect％22％2F％3E％0A％20％20％20％20％3C％2FclipPath％3E％0A％20％20％20％3C％2Fdefs％3E％0A％20％20 ％3Cuse％20fill％3D％22％23FFFC00％22％20stroke％3D％22black％22％20stroke-

码：

foreach (var username in File.ReadAllLines("/Users/admin/Desktop/snap-scraper/snap-scraper/snapchats.txt"))
{
    Console.WriteLine($"Attempting to grab QR for {username}");

    driver.Navigate().GoToUrl($"https://snapchat.com/add/{username}");

    Thread.Sleep(1000);

    var htmlDocument = new HtmlDocument();
    htmlDocument.LoadHtml(driver.PageSource);

    var image = htmlDocument.DocumentNode.SelectSingleNode("//img");

    if (image == null || !image.Attributes.Contains("src"))
    {
        Console.WriteLine($"Something went wrong for {username}");
        continue;
    }

    Console.WriteLine($"Got the QR for {username} yay");

    var src = image.Attributes.Where(x => x.Name == "src").First().Value;

    string filePath = $"/Users/admin/Desktop/snap-scraper/snap-scraper/images/{username}.jpg";
    File.WriteAllBytes(filePath, Convert.FromBase64String(src.Replace("-", "")));
}

Answer 1

不是Base64 。 这是URL Encoding 。 如果粘贴已编码的URL，则可以在URL解码器工具中看到此内容。

由于SVG由XML format因此不需要编码。

您可以使用WebUtility.UrlDecode（String）解码字符串，然后使用Encoding.GetBytes（String）将其转换为字节，然后将字节写入磁盘。

例：

foreach (var username in File.ReadAllLines("/Users/admin/Desktop/snap-scraper/snap-scraper/snapchats.txt"))
{
    Console.WriteLine($"Attempting to grab QR for {username}");

    driver.Navigate().GoToUrl($"https://snapchat.com/add/{username}");

    Thread.Sleep(1000);

    var htmlDocument = new HtmlDocument();
    htmlDocument.LoadHtml(driver.PageSource);

    var image = htmlDocument.DocumentNode.SelectSingleNode("//img");

    if (image == null || !image.Attributes.Contains("src"))
    {
        Console.WriteLine($"Something went wrong for {username}");
        continue;
    }

    Console.WriteLine($"Got the QR for {username} yay");

    var src = image.Attributes.Where(x => x.Name == "src").First().Value;

    string filePath = $"/Users/admin/Desktop/snap-scraper/snap-scraper/images/{username}.svg"; // This was .jpg

    // URL Decode Image - Remember to strip the start of the data url e.g. data:image/svg xml;utf8,
    string svg = WebUtility.UrlDecode(src).replace("data:image/svg xml;utf8,", "");

    // Convert SVG to byte array
    byte[] svgBytes = Encoding.UTF8.GetBytes(decodedUrl);

    // Write to byte array to disk
    File.WriteAllBytes(filePath, svg);
}