Tue 26 Aug 2003
GZip compression and changing UserAgent
Posted by mattcomroe under .Nizzle, BlogShares
Comments Off
Just in case you ever wanted to use the .NET Zip Library to receive GZip-compressed content from a webserver, as well as sending a custom UserAgent string to identify your app, here’s how you do it:
/// <summary>
/// Used to send out a custom application UserAgent, and return a string from a GZip-compressed
/// response.
/// </summary>
/// <param name="strUrl">The url you want to retrieve.</param>
/// <returns></returns>
public string GetWebRequest(string strUrl)
{
StringBuilder mySB = new StringBuilder();
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(strUrl);
// Sends the HttpWebRequest and waits for the response.
request.UserAgent = "BSClient 0.3";
request.Headers.Add("Accept-Encoding", "gzip, deflate");
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
// Gets the stream associated with the response.
Stream receiveStream = GetGzipStream(response);
Encoding encode = System.Text.Encoding.GetEncoding("utf-8");
// Pipes the stream to a higher level stream reader with the required encoding format.
StreamReader readStream = new StreamReader( receiveStream, encode );
Char[] read = new Char<sup><a href="#fn14497294114fbb16605008c">256</a></sup>;
// Reads 256 characters at a time.
int count = readStream.Read( read, 0, 256 );
while (count > 0)
{
// Dumps the 256 characters on a string and displays the string to the console.
String str = new String(read, 0, count);
mySB.Append(str);
count = readStream.Read(read, 0, 256);
}
// Releases the resources of the response.
response.Close();
// Releases the resources of the Stream.
readStream.Close();
return mySB.ToString();
}
/// <summary>
/// Used in place of GetResponseStream(). This function will check out your HttpWebResponse's contents,
/// and return the proper string representation of the HttpWebResponse stream.
/// </summary>
/// <param name="response"></param>
/// <returns>String representation of the HttpWebResponse</returns>
private Stream GetGzipStream(HttpWebResponse response)
{
Stream compressedStream = null;
if (response.ContentEncoding=="gzip")
{
compressedStream = new GZipInputStream(response.GetResponseStream());
}
else if (response.ContentEncoding=="deflate")
{
compressedStream = new InflaterInputStream(response.GetResponseStream());
}
if (compressedStream != null)
{
MemoryStream decompressedStream = new MemoryStream();
int size = 2048;
byte[] writeData = new byte<sup><a href="#fn20031112014fbb16605137c">2048</a></sup>;
while (true)
{
size = compressedStream.Read(writeData, 0, size);
if (size > 0)
{
decompressedStream.Write(writeData,0,size);
}
else
{
break;
}
}
decompressedStream.Seek(0, SeekOrigin.Begin);
return decompressedStream;
}
else
{
return response.GetResponseStream();
}
}
