上传 UIImage 类型的图像列表（Xamarin）

Posted 2023-03-30

【中文标题】上传 UIImage 类型的图像列表（Xamarin）

【英文标题】：Upload a list of images of type UIImage (Xamarin)

【发布时间】：2020-09-01 02:41:04

【问题描述】：

我的应用将从特定文件夹中检索所有图像的列表，并尝试通过 API 端点将它们上传到服务器

由于上述要求，图像选择器不适合

下面是共享代码中传递 UIImages 列表的方法（我现在正试图让它只与 ios 一起工作，但同样的场景最终也将应用于 android）

以下不起作用，因为当我在服务器（AWS）上查看图像时，它是代码格式。它还说内容类型是服务器上的 application/json 我不明白，因为我将它设置为 image/png

private async Task UploadImages(List<UIImage> images)
            
    HttpClient client = new HttpClient();
    var contentType = new MediaTypeWithQualityHeaderValue("image/png");
    client.DefaultRequestHeaders.Accept.Add(contentType);
    client.DefaultRequestHeaders.Add("Id-Token", Application.Current.Properties["id_token"].ToString());

    foreach (var image in images)
    
        try
                                                
            string baseUrl = $"https://********/dev/ferret-test/media/team1/user1/device1/test1.png";             
            client.BaseAddress = new Uri(baseUrl);

            //UploadModel uploadModel = new UploadModel
            //
            //    image_file = image.AsPNG()
            //;

            byte[] bArray = null;
            Stream pst = image.AsPNG().AsStream();
            using (MemoryStream ms = new MemoryStream())
            
                ms.Position = 0;
                pst.CopyTo(ms);
                bArray = ms.ToArray();
            

            //string stringData = JsonConvert.SerializeObject(bArray);
            //var contentData = new StringContent(stringData,
            //System.Text.Encoding.UTF8, "image/png");

            //Byte[] myByteArray = new Byte[imageData.Length];
            //System.Runtime.InteropServices.Marshal.Copy(imageData.Bytes, myByteArray, 0, Convert.ToInt32(imageData.Length));                        

            var postRequest = new HttpRequestMessage(HttpMethod.Put, baseUrl)
            
                Content = new ByteArrayContent(bArray)
            ;

            var response = await client.SendAsync(postRequest);
            response.EnsureSuccessStatusCode();
            string stringJWT = response.Content.ReadAsStringAsync().Result;   
        
        catch (Exception ex)
        
            Console.WriteLine(ex);
        
    
       

【问题讨论】：

现在可以用了吗？

【参考方案1】：

我用下面的sn-p存档了上传多个文件到服务器，你可以试试...

foreach (SQLiteAccess.Tables.Image image in images.OrderByDescending(x => x.Id)) //Here is the collection of all the file at once (Documents + Images)

      int documentId = UploadImageToServerAndroid(image).Result;
      // My other code implementation
      .
      .
      .


private async Task<int> UploadImageToServerAndroid(SQLiteAccess.Tables.Image image)
       
           int documentId = 0;

           if (!Admins.ConnectedToNetwork()) return documentId;

           MyFile = FileSystem.Current.GetFileFromPathAsync(image.Path).Result;

           if (MyFile == null) return documentId;
         
           Stream stream = MyFile.OpenAsync(FileAccess.Read).Result;

           byte[] byteArray;
           byteArray = new byte[stream.Length];
           stream.Read(byteArray, 0, (int)stream.Length);
           
           if( !image.IsDocument )
           
               try
               
                   byteArray = DependencyService.Get<IImageUtilities>().CompressImage(byteArray); //Its custom code to compress the Image.
               
               catch (Exception ex)
               
                   UoW.Logs.LogMessage(new LogDTO  Message = ex.Message, Ex = ex );
               
           
           string url = "Your URL";
           using (HttpClient client = new HttpClient(new RetryMessageHandler(new HttpClientHandler())))
           
               try
               
                   client.DefaultRequestHeaders.Add(Properties.Resources.Authorization, Sessions.BearerToken);
                   client.DefaultRequestHeaders.Add("DocumentSummary", image.Comment);
                   client.DefaultRequestHeaders.Add("DocumentName", Path.GetFileName(image.Path));
                   MultipartFormDataContent multiPartContent = new MultipartFormDataContent();
                   ByteArrayContent byteContent = new ByteArrayContent(byteArray);
                   byteContent.Headers.ContentType = MediaTypeHeaderValue.Parse("image/jpeg");
                   multiPartContent.Add(byteContent, "image", Path.GetFileName(image.Path));
                   HttpResponseMessage response = await client.PostAsync(url, multiPartContent);
                   if (response.IsSuccessStatusCode && response.Content != null)
                   
                       string jsonString = response.Content.ReadAsStringAsync().Result;
                       DocumentDTO result = JsonConvert.DeserializeObject<DocumentDTO>(jsonString);
                       documentId = result.DocumentId;
                   
               
               catch(Exception ex)
               
                   UoW.Logs.LogMessage( new LogDTO  Message = ex.Message, Ex = ex );
                   return documentId;
               
           
           return documentId;
       

如果 documentid 为 0（如果出现问题，出于任何原因），则将其标记为未上传，并在互联网可用时再次尝试上传。

如果您需要更多帮助，可以问...:)

【参考方案2】：

您可以尝试使用MultipartFormDataContent 并将内容类型设置为application/octet-stream。

你可以参考one和two这两个链接。