c# - Flask 服务器 - C# 客户端 - 发布图片

Question

我正在构建一个非常简单的应用程序，使用 Flask 作为服务器，C# 作为客户端。服务器通过 HTTP POST 请求接收图像并对其进行处理。我的服务器似乎工作正常，因为我使用 Postman 和 python 客户端对其进行了测试。但是，从我的 C# 客户端附加图像的 POST 请求无法传递到服务器。我已经使用 HttpClient 和 Restsharp 进行了测试，但没有任何效果，服务器提示没有附加图像。

这是我的服务器代码:

from flask import Flask, jsonify
from flask import abort
from flask import make_response
from flask import request, Response
from flask import url_for
from werkzeug.utils import secure_filename
import jsonpickle
import numpy as np
import cv2
import os
import json
import io

app = Flask(__name__)
UPLOAD_FOLDER = os.path.basename('uploads')
ALLOWED_EXTENSIONS = set(['png', 'jpg', 'jpeg', 'gif', 'mp4', '3gp', 'mov'])
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER
app.config['MAX_CONTENT_LENGTH'] = 16 * 1024 * 1024 # 16 MB

@app.route('/upload', methods=['POST'])
def upload():

file = request.files['file']
filename = secure_filename(file.filename)

in_memory_file = io.BytesIO()
file.save(in_memory_file)
data = np.fromstring(in_memory_file.getvalue(), dtype=np.uint8)
color_image_flag = 1
img = cv2.imdecode(data, color_image_flag)

cv2.imwrite("uploads\\" + file.filename, img)

这是我使用 Restsharp 的客户端代码

public void Test()
    {
        var client = new RestClient("http://127.0.0.1:5000/upload");
        var request = new RestRequest(Method.POST);
        request.AddHeader("content-type", "multipart/form-data; boundary=----Boundary");
        request.AddParameter("multipart/form-data; boundary=----Boundary", "------Boundary\r\nContent-Disposition: form-data; name=\"file\"; filename=\"path\"\r\nContent-Type: image/jpeg\r\n\r\n\r\n------Boundary--", ParameterType.RequestBody);
        IRestResponse response = client.Execute(request);
    }

这是使用 HttpClient 的客户端代码

public void Upload()
    {
        string path = "path";
        FileInfo fi = new FileInfo(path);
        string fileName = fi.Name;
        byte[] fileContents = File.ReadAllBytes(fi.FullName);

        Uri webService = new Uri(@"http://127.0.0.1:5000/upload");
        HttpRequestMessage requestMessage = new HttpRequestMessage(HttpMethod.Post, webService);
        requestMessage.Headers.ExpectContinue = false;

        MultipartFormDataContent multiPartContent = new MultipartFormDataContent("----MyGreatBoundary");
        ByteArrayContent byteArrayContent = new ByteArrayContent(fileContents);
        byteArrayContent.Headers.Add("Content-Type", "application/octet-stream");
        multiPartContent.Add(byteArrayContent, "this is the name of the content", fileName);
        requestMessage.Content = multiPartContent;

        HttpClient httpClient = new HttpClient();
        Task<HttpResponseMessage> httpRequest = httpClient.SendAsync(requestMessage, HttpCompletionOption.ResponseContentRead, CancellationToken.None);
        HttpResponseMessage httpResponse = httpRequest.Result;
    }

Answer 1

您需要在 C# 代码中将 name 参数设置为 "file" 而不是 "this is the name of the content" .

multiPartContent.Add(byteArrayContent, "file", "image.jpg");

这是一个可以实现这一目的的精简方法:

public Task<HttpResponseMessage> UploadAsFormDataContent(string url, byte[] image)
{
    MultipartFormDataContent form = new MultipartFormDataContent
    {
        { new ByteArrayContent(image, 0, image.Length), "file", "pic.jpeg" }
    };

    HttpClient client = new HttpClient();
    return client.PostAsync(url, form);
}