c# - Unrecognized response when run HTTP POST via HttpClient?

Question

I've got an issue that when I run a HTTP POST via HttpClient. I used it upload firmware to ESP8266 Arduino's OTA firmware upgrade interface (see sample: https://github.com/esp8266/Arduino/tree/master/libraries/ESP8266HTTPUpdateServer/examples), but it throws an exception saying

"WinHttpException: The server returned an invalid or unrecognized response"

When I upload the firmware image by cURL, it works totally fine with command below:

curl -F "[email protected]" 192.168.1.104/update

I've tried debugging with Fiddler, it told me I've got 504 Gateway Timeout. But it won't happen if I use cURL.

I guess it might be caused by some bugs inside ESP8266 Firmware OTA update API, and my program didn't generate a header which can "satisfy" the API, so it was somehow rejected. If possible, I would like to ask that is there any workaround for this issue? Thanks in advance!

Here is the cURL's raw result captured by Fiddler:

POST http://192.168.1.104/update HTTP/1.1
Host: 192.168.1.104
User-Agent: curl/7.51.0
Accept: */*
Connection: Keep-Alive
Content-Length: 335869
Expect: 100-continue
Content-Type: multipart/form-data; boundary=------------------------32e3208a349a700d

--------------------------32e3208a349a700d
Content-Disposition: form-data; name="image"; filename="firmware.bin"
Content-Type: application/octet-stream

.......(Firmware File Content).......

Here is my program's raw result:

POST http://192.168.1.104/update HTTP/1.1
Connection: Keep-Alive
Content-Type: multipart/form-data; boundary="----TwilightFirmware"
Accept-Encoding: gzip, deflate
Content-Length: 335857
Host: 192.168.1.104

------TwilightFirmware
Content-Type: application/octet-stream
Content-Disposition: form-data; name=update; filename=firmware.bin; filename*=utf-8''firmware.bin

.............(Firmware file Content)...........

Here is my (part of) C# code,

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
using System.Net.Http;
using System.Diagnostics;


namespace JasmineApp.Core
{
    class LocalFirmwareUpdater
    {
        public async Task<bool> UploadLocalFirmware(string baseUrl, string filePath)
        {
            Debug.WriteLine("[Core.FirmwareUpdater] Base URL is: " + baseUrl);
            HttpCommandHandler httpHandler = new HttpCommandHandler();
            httpHandler.SetHttpBaseUrl(baseUrl);

            byte[] firmwareContent = File.ReadAllBytes(filePath);

            // HttpContent postContent = new StreamContent(firmwareStream);
            HttpContent postContent = new ByteArrayContent(firmwareContent);
            postContent.Headers.Add("Content-Type", "application/octet-stream");

            var formData = new MultipartFormDataContent("----TwilightFirmware");
            formData.Add(postContent, "update", "firmware.bin");
            string result = await httpHandler.ExecutePostAsync("/update", formData);
            // string result = await httpHandler.ExecutePostAsync("/update", postContent);

            return (
                result.Equals(string.Empty) 
                || result == null 
                || result.Contains("Fail")) ? false : true;
        }
    }
}

...and HTTP handler code is here:

    public async Task<string> ExecutePostAsync(string pathAndQuery, MultipartFormDataContent content)
    {
        Debug.WriteLine("[Core.HttpHandler] Request POST URL: " + BaseUrl + pathAndQuery);

        using(var client = this.getHttpClient())
        {
            client.Timeout = TimeSpan.FromSeconds(2000000);
            var httpResponseMessage = client.PostAsync(pathAndQuery, content).Result;


            if(httpResponseMessage != null)
            {
                string responseResult = await httpResponseMessage.Content.ReadAsStringAsync();
                Debug.WriteLine("[Core.HttpCommandHandler] POST return message: " + httpResponseMessage.Content.ReadAsStringAsync().Result);
                return responseResult;
            }
            else
            {
                // Return an empty string to avoid exceptions
                // Don't need to worrry if it's empty.
                return string.Empty;
            }
        }

By the way, you can have a look for my full code on GitHub if necessary. Here's the link: https://github.com/huming2207/JasmineApp.Windows

emirsnck · Accepted Answer · 2017-02-20 05:18:24Z

1

Hello jackson you should change esp software. you dont use https://github.com/esp8266/Arduino/tree/master/libraries/ESP8266HTTPUpdateServer/examples because we uploaded server side. you can use https://github.com/esp8266/Arduino/blob/master/libraries/ESP8266WebServer/examples/WebUpdate/WebUpdate.ino this example and you will change this part

 server.on("/update", HTTP_POST, [](){
  server.sendHeader("Connection", "close");
  server.sendHeader("Access-Control-Allow-Methods", "GET, POST, PUT");
  server.sendHeader("Access-Control-Allow-Headers","Origin, X-Requested-With, Content-Type, Accept, Authorization");
  server.send(200, "text/plain", (Update.hasError())?"FAIL":"OK");
  ESP.restart();
}

I hope resolve your problem :) enjoy coding

answered Feb 20, 2017 at 5:18

emirsnck

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Comments

Richard Schneider · Accepted Answer · 2017-02-20 05:25:26Z

0

Try using the "image" name

formData.Add(postContent, "image", "firmware.bin");

answered Feb 20, 2017 at 5:25

Richard Schneider

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1 Comment

Jackson Ming Hu Over a year ago

I've tried it before, still remains the same actually

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