A method for making HTTP requests on Unity iOS?

Ok, I finally managed to write my own solution. We basically need a RequestState, a Callback Method and a TimeOut Thread. Here I'll just copy what was done in UnifyCommunity (now called unity3d wiki). This is outdated code, but smaller than what's there, so more convenient to show something here. Now I've removed (in the unit3d wiki) System.Action and static for performance and simplicity:

Usage

static public ThisClass Instance;void Awake () {    Instance = GetComponent<ThisClass>();}static private IEnumerator CheckAvailabilityNow () {    bool foundURL;    string checkThisURL = "http://www.example.com/index.html";    yield return Instance.StartCoroutine(        WebAsync.CheckForMissingURL(checkThisURL, value => foundURL = !value)        );    Debug.Log("Does "+ checkThisURL +" exist? "+ foundURL);}

WebAsync.cs

using System;using System.IO;using System.Net;using System.Threading;using System.Collections;using UnityEngine;/// <summary>///  The RequestState class passes data across async calls./// </summary>public class RequestState{    public WebRequest webRequest;    public string errorMessage;    public RequestState ()    {        webRequest = null;        errorMessage = null;    }}public class WebAsync {    const int TIMEOUT = 10; // seconds    /// <summary>    /// If the URLs returns 404 or connection is broken, it's missing. Else, we suppose it's fine.    /// </summary>    /// <param name='url'>    /// A fully formated URL.    /// </param>    /// <param name='result'>    /// This will bring 'true' if 404 or connection broken and 'false' for everything else.    /// Use it as this, where "value" is a System sintaxe:    /// value => your-bool-var = value    /// </param>    static public IEnumerator CheckForMissingURL (string url, System.Action<bool> result) {        result(false);        Uri httpSite = new Uri(url);        WebRequest webRequest = WebRequest.Create(httpSite);        // We need no more than HTTP's head        webRequest.Method = "HEAD";        RequestState requestState = new RequestState();        // Put the request into the state object so it can be passed around        requestState.webRequest = webRequest;        // Do the actual async call here        IAsyncResult asyncResult = (IAsyncResult) webRequest.BeginGetResponse(            new AsyncCallback(RespCallback), requestState);        // WebRequest timeout won't work in async calls, so we need this instead        ThreadPool.RegisterWaitForSingleObject(            asyncResult.AsyncWaitHandle,            new WaitOrTimerCallback(ScanTimeoutCallback),            requestState,            (TIMEOUT *1000), // obviously because this is in miliseconds            true            );        // Wait until the the call is completed        while (!asyncResult.IsCompleted) { yield return null; }        // Deal up with the results        if (requestState.errorMessage != null) {            if ( requestState.errorMessage.Contains("404") || requestState.errorMessage.Contains("NameResolutionFailure") ) {                result(true);            } else {                Debug.LogWarning("[WebAsync] Error trying to verify if URL '"+ url +"' exists: "+ requestState.errorMessage);            }        }    }    static private void RespCallback (IAsyncResult asyncResult) {        RequestState requestState = (RequestState) asyncResult.AsyncState;        WebRequest webRequest = requestState.webRequest;        try {            webRequest.EndGetResponse(asyncResult);        } catch (WebException webException) {            requestState.errorMessage = webException.Message;        }    }    static private void ScanTimeoutCallback (object state, bool timedOut)  {         if (timedOut)  {            RequestState requestState = (RequestState)state;            if (requestState != null)                 requestState.webRequest.Abort();        } else {            RegisteredWaitHandle registeredWaitHandle = (RegisteredWaitHandle)state;            if (registeredWaitHandle != null)                registeredWaitHandle.Unregister(null);        }    }}

I got threading to work on iOS- I believe it was crashing due to ghost threads or something. Restarting the device seems to have fixed the crashing so I'll just use WebRequest.HttpWebRequest with threads.

There is a way of doing this asynchronously, without using IEnumerator and yield return stuff. Check out the eDriven framework.

HttpConnector class: https://github.com/dkozar/eDriven/blob/master/eDriven.Networking/Rpc/Core/HttpConnector.cs

I've been using JsonFX with HttpConnector all the time, for instance in this WebPlayer demo: http://edrivenunity.com/load-images

Not having PUT and DELETE is not a big issue, since all of it could be done using GET and POST. For instance I'm successfully communicating with Drupal CMS using its REST service.