/// <summary>
/// Begins an asynchronous request
/// </summary>
/// <param name="useCache">true to use cache, otherwise false</param>
/// <param name="timeOut">timeout, in milliseconds</param>
public void StartRequest(CacheSettings cacheSettings, int timeOut)
{
requestRunning = true;
// Check the cache
if (cacheSettings != CacheSettings.NOCACHE)
{
Internet_Cache_Entry_Info cacheInfo;
if (WinInet.GetUrlCacheEntryInfo(m_url, out cacheInfo))
{
ResponseStream = new FileStream(cacheInfo.lpszLocalFileName, FileMode.Open, FileAccess.Read);
FireRequestComplete();
}
}
// Make an async request
if (ResponseStream == null && cacheSettings != CacheSettings.CACHEONLY)
{
try
{
m_webRequest = HttpRequestHelper.CreateHttpWebRequest(m_url, true);
}
catch (InvalidCastException)
{
m_webRequest = WebRequest.Create(m_url);
}
m_webRequest.Timeout = timeOut;
m_webRequest.BeginGetResponse(new AsyncCallback(RequestCompleteHandler), new object());
}
}
/// <summary>
/// Synchronously retrieves a response stream for this request
/// </summary>
/// <param name="timeOut">timeout, in ms</param>
/// <param name="useCache">true to use cache, otherwise false</param>
/// <returns>The stream</returns>
public Stream GetResponseStream(CacheSettings cacheSettings, int timeOut)
{
Stream stream = Stream.Null;
// Check the cache
if (cacheSettings != CacheSettings.NOCACHE)
{
Internet_Cache_Entry_Info cacheInfo;
if (WinInet.GetUrlCacheEntryInfo(m_url, out cacheInfo))
{
if (File.Exists(cacheInfo.lpszLocalFileName))
{
stream = new FileStream(cacheInfo.lpszLocalFileName, FileMode.Open, FileAccess.Read);
}
}
}
// Make a synchronous request, if necessary
if (stream == Stream.Null && cacheSettings != CacheSettings.CACHEONLY)
{
if (m_url == null)
{
return(null);
}
if (WebRequest is HttpWebRequest)
{
HttpWebRequest thisRequest = (HttpWebRequest)WebRequest;
thisRequest.Timeout = timeOut;
}
try
{
stream = WebRequest.GetResponse().GetResponseStream();
}
catch (WebException)
{
}
}
return(stream);
}
/// <summary>
/// Retrieve the resource with the specified timeout (in ms).
/// </summary>
/// <param name="timeoutMs">Timeout (in ms) for the request.</param>
/// <returns>A stream representing the requested resource. Can return null
/// if the CacheLevel is CacheOnly and the resource could not be found
/// in the cache.</returns>
public Stream GetResponse(int timeoutMs)
{
// always try to get the url from the cache first
if (ReadFromCache)
{
Internet_Cache_Entry_Info cacheInfo;
if (WinInet.GetUrlCacheEntryInfo(_requestUrl, out cacheInfo))
{
if (File.Exists(cacheInfo.lpszLocalFileName))
{
return(new FileStream(cacheInfo.lpszLocalFileName, FileMode.Open, FileAccess.Read));
}
}
}
// if that didn't succeed then try to get the file from
// the web as long as the user has requested we do this
if (MakeRequest)
{
HttpWebResponse response = HttpRequestHelper.SendRequest(_requestUrl, delegate(HttpWebRequest request)
{
request.AllowAutoRedirect = AllowAutoRedirect;
request.Timeout = timeoutMs;
request.ContentType = ContentType;
if (PostData != null)
{
request.Method = "POST";
using (Stream requestStream = request.GetRequestStream())
StreamHelper.Transfer(new MemoryStream(PostData), requestStream);
}
});
try
{
Stream responseStream = response.GetResponseStream();
if (responseStream != null)
{
if (WriteToCache)
{
return(WriteResponseToCache(responseStream));
}
else
{
return(StreamHelper.CopyToMemoryStream(responseStream));
}
}
else
{
return(null);
}
}
finally
{
response.Close();
}
}
else
{
// look only in the cache
return(null);
}
}
/// <summary>
/// Looks up the content type in browser cache
/// </summary>
/// <param name="url">The url for which to check content type</param>
/// <returns>The content type</returns>
private static UrlContentTypeInfo GetContentTypeFromBrowserCache(string url)
{
UrlContentTypeInfo contentType = null;
// throw out the query string and other bits of the url, if we can
if (UrlHelper.IsUrl(url))
{
Uri uri = new Uri(url);
// by using the absolute uri, we're more likely to hit the cache
url = UrlHelper.SafeToAbsoluteUri(uri);
}
// Get the header for this URL out of the cache and see if we
// can get the content type out of the header
Internet_Cache_Entry_Info info;
if (WinInet.GetUrlCacheEntryInfo(url, out info))
{
// Get the header string for the info struct
string header = Marshal.PtrToStringAnsi(info.lpHeaderInfo);
// scan through the lines until we find the content type line
if (header != null)
{
string contentTypeString = null;
string contentLengthString = null;
string contentEncodingString = null;
string[] lines = header.Split('\n');
foreach (string line in lines)
{
if (line.IndexOf(":", StringComparison.OrdinalIgnoreCase) > -1)
{
string[] parts = line.Split(':');
if (parts[0].ToUpperInvariant() == "CONTENT-TYPE")
{
// be aware the character encoding can be appended to the end of this line
// following a semicolon
if (parts[0].IndexOf(";", StringComparison.OrdinalIgnoreCase) > -1)
{
string[] subParts = parts[0].Split(';');
contentTypeString = subParts[0].Trim();
contentEncodingString = subParts[1].Trim();
}
else
{
contentTypeString = parts[1].Trim();
}
}
else if (parts[0].ToUpperInvariant() == "CONTENT-LENGTH")
{
contentLengthString = parts[1].Trim();
}
if (contentTypeString != null && contentLengthString != null)
{
break;
}
}
}
contentType = new UrlContentTypeInfo(contentTypeString, contentEncodingString, url, int.Parse(contentLengthString, CultureInfo.InvariantCulture));
}
}
return(contentType);
}
