Azure Functions call http post inside function

For anyone else who lands here when searching for HttpClient in Azure functions.

https://docs.microsoft.com/en-us/azure/azure-functions/manage-connections

// Create a single, static HttpClientprivate static HttpClient httpClient = new HttpClient();public static async Task Run(string input){    var response = await httpClient.GetAsync("https://example.com");    // Rest of function}

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?

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