WWW basic request helper example

using UnityEngine;
using UnityEngine.Events;
using System.Collections;

public class WWWHelper : MonoBehaviour // Must inherit from Monobehaviour to run coroutines
{
    private static WWWHelper _instance; // there must be an instance of the class.
                                        // since it derives from MonoBehaviour it must also be added to a gameObjct as a component.

    private const float TIMEOUT = 5f; // a timeout if we need it.

    public const string TIMEOUT_RESPONSE = "TIMEOUT";
    public const string ERROR_PREFIX = "ERROR - ";

    // convenience method for easy access
    public static void MakeRequest(string url, UnityAction<string> callback)
    {
        if (_instance == null)
        {
            // create a game object to put this script on
            GameObject go = new GameObject("WWWHelper");

            // add this script to it and store it in _instance
            _instance = go.AddComponent<WWWHelper>();
        }

        _instance.StartCoroutine(_instance.RequestCoroutine(url, callback));
    }

    // Since coroutines cannot return a value, we usually use callbacks / delegates / actions
    private IEnumerator RequestCoroutine(string url, UnityAction<string> callback)
    {
        WWW request = new WWW(url);

        float timer = 0;

        while (timer < TIMEOUT)
        {
            timer += Time.deltaTime; // increment our timer every frame

            if (request.isDone) // if the request is done, no need to wait
                break;

            yield return new WaitForEndOfFrame(); // wait for the frame to complete before continuing this loop
        }

        string response = TIMEOUT_RESPONSE;

        if (request.isDone)
        {
            if (!string.IsNullOrEmpty(request.error))
                response = request.error;
            else
                response = request.text;
        }

        if (callback != null)
            callback.Invoke(response); // finally call the callback so we can hear about the response.
    }
}

public class Example : MonoBehaviour
{
    private void Start()
    {
        WWWHelper.MakeRequest("www.naplandgames.com", HandleResponse);
    }

    private void HandleResponse(string response)
    {
        if (response == WWWHelper.TIMEOUT_RESPONSE)
        {
            Debug.LogError("Hey user, the response timed out, your internet sucks");
        }
        else if (response.Contains(WWWHelper.ERROR_PREFIX))
        {
            Debug.LogError("Hey developer, your requested URL stunk, here's the error: " + response);
        }
        else
        {
            Debug.Log("Hey user, here's the response: " + response);
        }
    }
}