WWW DSL using Irony - Part 1

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.IO;
using Irony.Runtime;
using System.Threading;

namespace WWWDSL
{
    static class DownloadWebPage
    {
        static private void WaitWithAbortCheck(WebRequest request, IAsyncResult aRes, EvaluationContext evalContext)
        {
            while (!aRes.IsCompleted)
            {
                Thread.Sleep(100);
                try
                {
                    evalContext.GetProcessingContext().AbortedCheck();
                }
                catch
                {
                    request.Abort();
                    throw;
                }
            }
        }

        static public string DownloadWWWPage(string url, string method, string referer, string postData, 
                                             EvaluationContext evalContext)
        {
            HttpWebRequest webRequestObject = (HttpWebRequest)HttpWebRequest.Create(url);

            webRequestObject.UserAgent = "WWW DSL 1.0";
            webRequestObject.Method = method;
            if (referer != null)
            {
                webRequestObject.Referer = referer;
            }

            if (postData != null)
            {
                ((WwwDslEvaluationContext)evalContext).OnProgressChange("Sending request", -1);
                
                ASCIIEncoding encoding = new ASCIIEncoding();
                byte[] data = encoding.GetBytes(postData);
                webRequestObject.ContentType = "application/x-www-form-urlencoded";
                //webRequestObject.ContentLength = data.Length;
                IAsyncResult aRes = webRequestObject.BeginGetRequestStream(null, null);
                WaitWithAbortCheck(webRequestObject, aRes, evalContext);
                using (Stream newStream = webRequestObject.EndGetRequestStream(aRes))// BeginGetRequestStream( GetRequestStream();
                {
                    // Send the data.
                    aRes = newStream.BeginWrite(data, 0, data.Length, null, null);
                    WaitWithAbortCheck(webRequestObject, aRes, evalContext);
                    newStream.EndWrite(aRes);
                }
                
                ((WwwDslEvaluationContext)evalContext).OnProgressChange("Request sent", -1);
            }

            ((WwwDslEvaluationContext)evalContext).OnProgressChange("Getting response", -1);
            string result;
            IAsyncResult aResult = webRequestObject.BeginGetResponse(null, null);
            WaitWithAbortCheck(webRequestObject, aResult, evalContext);
            using (WebResponse response = webRequestObject.EndGetResponse(aResult))
            {
                ((WwwDslEvaluationContext)evalContext).OnLogAction(
                    string.Format("URL:{0}, download from:{1}", url, response.ResponseUri.ToString()));
                using (Stream webStream = response.GetResponseStream())
                {
                    using (StreamReader reader = new StreamReader(webStream))
                    {
                        result = reader.ReadToEnd();
                    }
                }
            }
            ((WwwDslEvaluationContext)evalContext).OnProgressChange("Response obtained", -1);

            return result;
        }

        static public void DownloadFile(string url, string path, EvaluationContext evalContext)
        {
            HttpWebRequest webRequestObject = (HttpWebRequest)HttpWebRequest.Create(url);

            webRequestObject.UserAgent = "WWW DSL 1.0";

            ((WwwDslEvaluationContext)evalContext).OnProgressChange("Starting download", -1);

            //WebResponse Response = webRequestObject.GetResponse();
            IAsyncResult aResult = webRequestObject.BeginGetResponse(null, null);
            WaitWithAbortCheck(webRequestObject, aResult, evalContext);
            using (WebResponse response = webRequestObject.EndGetResponse(aResult))
            {
                ((WwwDslEvaluationContext)evalContext).OnLogAction(
                    string.Format("URL:{0}, download from:{1}",url, response.ResponseUri.ToString()));
                using (Stream webStream = response.GetResponseStream())
                {
                    long filesize = response.ContentLength;
                    string fullPath = Path.Combine(path, Uri.UnescapeDataString(response.ResponseUri.Segments.Last()));
                    using (FileStream fs = new FileStream(fullPath, FileMode.Create, FileAccess.Write))
                    {
                        const int size = 4096;
                        byte[] bytes = new byte[size];
                        int numBytes;
                        long downloadedsize = 0;
                        DateTime start = DateTime.Now;

                        while ((numBytes = webStream.Read(bytes, 0, size)) > 0)
                        {
                            evalContext.GetProcessingContext().AbortedCheck();
                            fs.Write(bytes, 0, numBytes);
                            downloadedsize += numBytes;
                            if ((DateTime.Now - start).TotalSeconds > 0)
                            {
                                ((WwwDslEvaluationContext)evalContext).OnProgressChange(
                                    String.Format("Downloaded {0} kB ({1:F3} Mb/s)",
                                    downloadedsize / 1024,
                                    8 * downloadedsize / (DateTime.Now - start).TotalSeconds / 1e6),
                                    (int)(100 * downloadedsize / (double)filesize),
                                    false);
                            }
                            else
                            {
                                ((WwwDslEvaluationContext)evalContext).OnProgressChange(
                                    String.Format("Downloaded {0} kB", downloadedsize / 1024),
                                    (int)(100 * downloadedsize / (double)filesize),
                                    false);
                            }
                        }
                    }
                }
            }

            ((WwwDslEvaluationContext)evalContext).OnProgressChange("Download finished", -1);
        }
    }
}