将图像文件从控制台应用程序作为 IFormFile 参数发布到 API

Question

我需要将图像从 Asp.Net Core 控制台应用程序上传到 API。

发布到的 API 看起来像这样，并且在使用 Postman 测试时可以正常工作：

[HttpPost("UploadImage")]
public async Task<string> UploadImage(IFormFile files)
{
      // stuff happens here
}

将文件从控制台应用程序发布到此代码会是什么样子？ 谢谢

Answer 1

我需要从 Asp.Net Core 控制台应用程序将图像上传到 API。

要实现从Console应用发送图片到API后端的HTTP请求，可以参考以下代码sn-p。

var _httpClient = new HttpClient();

var formContent = new MultipartFormDataContent();

var FilePath = @"D:\xxx\pic1.PNG";

formContent.Add(new StreamContent(File.OpenRead(FilePath)), "files", Path.GetFileName(FilePath));

_httpClient.BaseAddress = new Uri("https://localhost:44312/");

var response = await _httpClient.PostAsync("/UploadImage", formContent);

if (response.IsSuccessStatusCode)
{
    //....
    //code logic here
    //...
}

Answer 2

我有一个包含表单文件操作的库。 ConvertToFormFile 方法在我的库中。但是由于 Memory Stream，您不能使用外部程序集。因此，您可以在自己的类中定义此方法，也可以将其定义为扩展方法。

 public class ProductDTO {

    private string _imageBase64String;
    
    public int Id { get; set; }

    public string ImageBase64String
    {
        get => _imageBase64String;
        set
        {
            if (!string.IsNullOrEmpty(value))
            {
                 Image = ConvertToFormFile(value);
            }
            _imageBase64String = value;
        }
    }

    public IFormFile Image { get; set; }



    /// <summary>
    /// Converts data URI formatted base64 string to IFormFile.
    /// </summary>
    /// <param name="milvaBase64"></param>
    /// <returns></returns>
    private IFormFile ConvertToFormFile(string milvaBase64)
    {
        var splittedBase64String = milvaBase64.Split(";base64,");
        var base64String = splittedBase64String?[1];

        var contentType = splittedBase64String[0].Split(':')[1];

        var splittedContentType = contentType.Split('/');

        var fileType = splittedContentType?[0];

        var fileExtension = splittedContentType?[1];

        var array = Convert.FromBase64String(base64String);

        var memoryStream = new MemoryStream(array)
        {
            Position = 0
        };

        return new FormFile(memoryStream, 0, memoryStream.Length, fileType, $"File.{fileExtension}")
        {
            Headers = new HeaderDictionary(),
            ContentType = contentType
        };
    }
}

uri 格式的 base64 字符串示例数据：data:image/jpeg;base64,/9j/2wCEAAgGBgcGBQgHBwcJCQgKDBQNDAsLDB...

然后您可以使用我的库来保存图像或做其他事情。如下所示；

public class ProductService{
  
    ...

    private readonly IStringLocalizer<ProductService> _localizer;

    ...

    public async Task SaveProductImage(ProductDTO productDTO)
    {
         
       var imagePath = await productDTO.Image.SaveImageToServerAsync<ProductDTO, int>(productDTO, _localizer).ConfigureAwait(false);

    }
 }

public static class HelperExtension{

    /// <summary>
    /// Save uploaded IFormFile file to server. Target Path will be : ".../wwwroot/Media Library/Image Library/<paramref name="entity"></paramref>.Id"
    /// </summary>
    /// <returns></returns>
    public static async Task<string> SaveImageToServerAsync<TEntity, TKey>(this IFormFile file, TEntity entity, IStringLocalizer stringLocalizer) where TEntity : AuditableEntity<OpsiyonUser, Guid, TKey>
                                                                                                                                                  where TKey : struct, IEquatable<TKey>
    {
        string basePath = GlobalConstants.ImageLibraryPath;

        FormFileOperations.FilesFolderNameCreator imagesFolderNameCreator = CreateImageFolderNameFromDTO;

        string propertyName = "Id";

        int maxFileLength = 14000000;

        var allowedFileExtensions = GlobalConstants.AllowedFileExtensions.Find(i => i.FileType == FileType.Image.ToString()).AllowedExtensions;

        var validationResult = file.ValidateFile(FileType.Image, maxFileLength, allowedFileExtensions);

        switch (validationResult)
        {
            case FileValidationResult.Valid:
                break;
            case FileValidationResult.FileSizeTooBig:
                // Get length of file in bytes
                long fileSizeInBytes = file.Length;
                // Convert the bytes to Kilobytes (1 KB = 1024 Bytes)
                double fileSizeInKB = fileSizeInBytes / 1024;
                // Convert the KB to MegaBytes (1 MB = 1024 KBytes)
                double fileSizeInMB = fileSizeInKB / 1024;
                throw new MilvaValidationException(stringLocalizer["FileIsTooBigMessage", fileSizeInMB.ToString("0.#")]);
            case FileValidationResult.InvalidFileExtension:
                var stringBuilder = new StringBuilder();
                throw new MilvaValidationException(stringLocalizer["UnsupportedFileTypeMessage", stringBuilder.AppendJoin(", ", allowedFileExtensions)]);
            case FileValidationResult.NullFile:
                return "";
        }

        var path = await file.SaveFileToPathAsync(entity, basePath, imagesFolderNameCreator, propertyName).ConfigureAwait(false);

        await file.OpenReadStream().DisposeAsync().ConfigureAwait(false);

        return path;
    }


    private static string CreateImageFolderNameFromDTO(Type type)
    {
        return type.Name.Split("DTO")[0] + "Images";
    }

}

或者您可以在 FormFileOperations.cs 中使用此方法，如下所示；

   public async Task<IFormFile> GetFile()
    {
        var path = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "test.jpg");

        return await FormFileOperations.GetFileFromPathAsync(path, FileType.Image).ConfigureAwait(false);
    }

并使用 HttpClient 发送请求。

关于我的图书馆的详细信息请看一下；

Github link

Nuget link

我还没有创建文档，但是代码内文档随处可见。我的目标是在未来把它变成一个框架。如果你能做出贡献，我会很高兴。

希望对你有帮助。