Azure Functions call http post inside function

Question

Is it possible to create HTTP(s) post request inside Azure Function? I am trying to create a custom webhook that is listening to one service and when triggered then its calling another service over HTTP using post.

My code looks like that:

public static async Task<HttpResponseMessage> Run(HttpRequestMessage req, TraceWriter log)
{

    BitbucketRequest data = await req.Content.ReadAsAsync<BitbucketRequest>();
    //DO STH WITH DATA TO GET e.g. USER STORY ID

    using(var client = new HttpClient()){
        client.BaseAddress = new Uri("https://SOME_TARGETPROCESS_URL/api/v1");
        var body = new { EntityState = new  { Id = 174 } };
        var result = await client.PostAsJsonAsync(
                       "/UserStories/7034/?resultFormat=json&access_token=MYACCESSTOKEN",
                       body);
        string resultContent = await result.Content.ReadAsStringAsync();
    }

    return req.CreateResponse<string>(HttpStatusCode.OK,"OKOK");
}

I suppose the problem is that currently HttpRequestMessage is occupying web socket and I can not create new Http Request.

Errors that I found in Exceptions details:

• The underlying connection was closed: An unexpected error occurred on a send.
• Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.
• Socket Exception Error Code : 10054

Answer 1

I just spent quite a few hours myself trying to get this to work. This was in NodeJS. The thing I figured out, was that I apparently needed to have an endpoint running HTTPS, and with a valid certificate.

Not sure if this is documented anywhere.

Answer 2

It is certainly possible and the following code block works just fine in my test function:

using(var client = new HttpClient())
{
    client.BaseAddress = new Uri("https://www.google.com");
    var result = await client.GetAsync("");
    string resultContent = await result.Content.ReadAsStringAsync();
    log.Info(resultContent);
}

It prints out HTML of google.com. POST also works: returns Error 405 (Method Not Allowed)!!1 from google.

Can it be that your callee is failing?

Answer 3

I've done the HTTP post inside Azure Function like so:

using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using Newtonsoft.Json;

public static async Task<HttpResponseMessage> Run(HttpRequestMessage req, string arg1, string arg2, string arg3, TraceWriter log)
{
    log.Info("C# HTTP trigger function processed a request.");
    var text = String.Format("arg1: {0}\narg2: {1}\narg3: {2}", arg1, arg2, arg3);
    log.Info(text);

    var results = await SendTelegramMessage(text);
    log.Info(String.Format("{0}", results));

    return req.CreateResponse(HttpStatusCode.OK);
}

public static async Task<string> SendTelegramMessage(string text)
{
    using (var client = new HttpClient())
    {

        Dictionary<string, string> dictionary = new Dictionary<string, string>();
        dictionary.Add("PARAM1", "VALUE1");
        dictionary.Add("PARAM2", text);

        string json = JsonConvert.SerializeObject(dictionary);
        var requestData = new StringContent(json, Encoding.UTF8, "application/json");

        var response = await client.PostAsync(String.Format("url"), requestData);
        var result = await response.Content.ReadAsStringAsync();

        return result;
    }
}

As you could guess by the name, I'm using this to send a POST request to a telegram bot