webClient.DownloadData 扔 'System.IO.PathTooLongException'

Question

我有一个方法是通过URL下载图片，有时URL变成这样，其中包含很长的路径（我删除了一些字符串，它只是没有成为长问题:)：

data:image/jpeg;base64,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

然后当我调试或下载图像时，我得到这个异常：

var DL = webClient.DownloadData(base64)
The specified path and / or file name is too long. The fully qualified name must be less than 260 characters and the folder name must be less than 248 characters.

我也研究了建议在 webconfig 中添加 <httpRuntime maxUrlLength="260" /> 或使用不同的库，但不幸的是它没有帮助解决问题。
任何人都可以帮助我或指出正确的方向:)
提前致谢。

控制器：

[HttpPost]
public string DownloadImagesFromLinkViaURL(ImagesViewModel model)
{
 var RandomName = Guid.NewGuid().ToString("N").Substring(0,12);
    using (WebClient webClient = new WebClient())
    {
        try
        {
            string base64 = model.ImageURL.Substring(model.ImageURL.IndexOf(',') + 1);
            byte[] data = Convert.FromBase64String(base64);
            var DL = webClient.DownloadData(base64);

            using (MemoryStream mem = new MemoryStream(DL))
            {
                using (var content = Image.FromStream(mem))
                {
                    var format = ImageFormat.Png.ToString().ToLower();

                    var PathIMG = "https://SomeName.com/folder/" + RandomName + "." + format;

                    content.Save(Path.Combine(Server.MapPath(PathIMG)));
                    ImageStore img = new ImageStore();

                    img.ProducentVarenr = model.ImageName;
                    img.ImageOrginalURL = model.ImageURL;
                    img.ImageRandomName = RandomName;
                    img.LinktilBillede = PathIMG;
                    db.ImageStoreList.Add(img);
                    db.SaveChanges();
                }
            }

        }
        catch (ArgumentException)
        {
            return "content is not image";
        }

    }
    return "saved";
}

视图模态：

public class ImagesViewModel
{
    public int ImageID { get; set; }
    public string ImageURL { get; set; }
    public string ImageName { get; set; }
    public string ImagePath { get; set; }
    public string RandomName { get; set; }
}

Answer 1

您看到的数据不是 url 或路径。它是显示为 Base64 字符串的图像数据。因为您已经有图像数据，所以不需要任何下载。

如果您粘贴 非常长的字符串 即 this base64 到图像转换器工具，您会看到实际图像。

使用给定的 base64 字符串，您可以将其保存到具有以下样式的文件中：

File.WriteAllBytes(@"c:\yourfile", Convert.FromBase64String(base64));

这是（未测试和未重构的）原始方法的固定版本，如回答评论中所要求。

[HttpPost]
public string DownloadImagesFromLinkViaURL(ImagesViewModel model)
{
    var RandomName = Guid.NewGuid().ToString("N").Substring(0, 12);
    var format = ImageFormat.Png.ToString().ToLower();

    var PathIMG = "https://SomeName.com/folder/" + RandomName + "." + format;
    if (model.ImageURL.StartsWith("data:image"))
    {
        string base64 = model.ImageURL.Substring(model.ImageURL.IndexOf(',') + 1);
        File.WriteAllBytes($@"c:\temp\{RandomName}.jpeg", Convert.FromBase64String(base64));
        ImageStore img = new ImageStore();

        img.ProducentVarenr = model.ImageName;
        img.ImageOrginalURL = model.ImageURL;
        img.ImageRandomName = RandomName;
        img.LinktilBillede = PathIMG;
        db.ImageStoreList.Add(img);
        db.SaveChanges();
        return "saved";
    }
    using (WebClient webClient = new WebClient())
    {
        try
        {
            byte[] data = Convert.FromBase64String(base64);
            var DL = webClient.DownloadData(base64);

            using (MemoryStream mem = new MemoryStream(DL))
            {
                using (var content = Image.FromStream(mem))
                {
                    content.Save(Path.Combine(Server.MapPath(PathIMG)));
                    ImageStore img = new ImageStore();

                    img.ProducentVarenr = model.ImageName;
                    img.ImageOrginalURL = model.ImageURL;
                    img.ImageRandomName = RandomName;
                    img.LinktilBillede = PathIMG;
                    db.ImageStoreList.Add(img);
                    db.SaveChanges();
                }
            }

        }
        catch (ArgumentException)
        {
            return "content is not image";
        }

    }
    return "saved";
}

webClient.DownloadData 扔 'System.IO.PathTooLongException'

webClient.DownloadData throw 'System.IO.PathTooLongException'

c#

system.io.file