(original version can be found here: http://www.123aspx.com/redir.aspx?res=29459)
First of all we create a class that does all the work
public class CompressionExtension : SoapExtension {
Stream _OldStream;
Stream _NewStream;
public override object GetInitializer(LogicalMethodInfo methodInfo,
SoapExtensionAttribute attribute) {
return attribute;
}
// Get the Type
public override object GetInitializer(Type t) {
return typeof(CompressionExtension);
}
// Get the CompressionExtensionAttribute
public override void Initialize(object initializer) {
if (initializer is CompressionExtensionAttribute) {
CompressionExtensionAttribute attribute =
(CompressionExtensionAttribute)initializer;
}
return;
}
// Process the SOAP Message
public override void ProcessMessage(SoapMessage message) {
// Check for the various SOAP Message Stages
switch (message.Stage) {
case SoapMessageStage.BeforeSerialize:
break;
case SoapMessageStage.AfterSerialize:
// ZIP the contents of the SOAP Body after it has
// been serialized
Zip();
break;
case SoapMessageStage.BeforeDeserialize:
// Unzip the contents of the SOAP Body before it is
// deserialized
Unzip();
break;
case SoapMessageStage.AfterDeserialize:
break;
default:
throw new Exception("invalid stage");
}
}
// Gives us the ability to get hold of the RAW SOAP message
public override Stream ChainStream(Stream stream) {
_OldStream = stream;
_NewStream = new MemoryStream();
return _NewStream;
}
// Utility method to copy streams
void Copy(Stream from, Stream to) {
TextReader reader = new StreamReader(from);
TextWriter writer = new StreamWriter(to);
writer.WriteLine(reader.ReadToEnd());
writer.Flush();
}
// Zip the SOAP Body
private void Zip() {
_NewStream.Position = 0;
// Zip the SOAP Body
_NewStream = ZipSoap(_NewStream);
// Copy the streams
Copy(_NewStream, _OldStream);
}
// The actual ZIP method
private byte[] Zip(string stringToZip) {
byte[] inputByteArray = Encoding.UTF8.GetBytes(stringToZip);
MemoryStream ms = new MemoryStream();
// Check the #ziplib docs for more information
GZipStream zipOut = new GZipStream(ms, CompressionMode.Compress);
zipOut.Write(inputByteArray, 0, inputByteArray.Length);
zipOut.Close();
// Return the zipped contents
return ms.ToArray();
}
// Select and Zip the appropriate parts of the SOAP message
public MemoryStream ZipSoap(Stream streamToZip) {
streamToZip.Position = 0;
// Load a XML Reader
XmlTextReader reader = new XmlTextReader(streamToZip);
XmlDocument dom = new XmlDocument();
dom.Load(reader);
// Load a NamespaceManager to enable XPath selection
XmlNamespaceManager nsmgr = new XmlNamespaceManager(dom.NameTable);
nsmgr.AddNamespace("soap", "http://schemas.xmlsoap.org/soap/envelope/");
XmlNode node = dom.SelectSingleNode("//soap:Body", nsmgr);
// Select the contents within the method defined in the SOAP body
node = node.FirstChild.FirstChild;
// Check if there are any nodes selected
while (node != null) {
if (node.InnerXml.Length > 0) {
// Zip the data
byte[] outData = Zip(node.InnerXml);
// Convert it to Base64 for transfer over the internet
node.InnerXml = Convert.ToBase64String(outData);
}
// Move to the next parameter
node = node.NextSibling;
}
MemoryStream ms = new MemoryStream();
// Save the updated data
dom.Save(ms);
ms.Position = 0;
return ms;
}
// Unzip the SOAP Body
private void Unzip() {
MemoryStream unzipedStream = new MemoryStream();
TextReader reader = new StreamReader(_OldStream);
TextWriter writer = new StreamWriter(unzipedStream);
writer.WriteLine(reader.ReadToEnd());
writer.Flush();
// Unzip the SOAP Body
unzipedStream = UnzipSoap(unzipedStream);
// Copy the streams
Copy(unzipedStream, _NewStream);
_NewStream.Position = 0;
}
// Actual Unzip logic
private byte[] Unzip(string stringToUnzip) {
// Decode the Base64 encoding
byte[] inputByteArray = Convert.FromBase64String(stringToUnzip);
MemoryStream ms = new MemoryStream(inputByteArray);
MemoryStream ret = new MemoryStream();
// Refer to #ziplib documentation for more info on this
GZipStream zipIn = new GZipStream(ms, CompressionMode.Decompress);
Byte[] buffer = new Byte[2048];
int size = 2048;
while (true) {
size = zipIn.Read(buffer, 0, buffer.Length);
if (size > 0) {
ret.Write(buffer, 0, size);
} else {
break;
}
}
return ret.ToArray();
}
// Unzip the SOAP Body
public MemoryStream UnzipSoap(Stream streamToUnzip) {
streamToUnzip.Position = 0;
// Load a XmlReader
XmlTextReader reader = new XmlTextReader(streamToUnzip);
XmlDocument dom = new XmlDocument();
dom.Load(reader);
XmlNamespaceManager nsmgr = new XmlNamespaceManager(dom.NameTable);
nsmgr.AddNamespace("soap", "http://schemas.xmlsoap.org/soap/envelope/");
// Select the SOAP Body node
XmlNode node = dom.SelectSingleNode("//soap:Body", nsmgr);
node = node.FirstChild.FirstChild;
// Check if node exists
while (node != null) {
if (node.InnerXml.Length > 0) {
// Send the node's contents to be unziped
byte[] outData = Unzip(node.InnerXml);
string sTmp = Encoding.UTF8.GetString(outData);
node.InnerXml = sTmp;
}
// Move to the next parameter
node = node.NextSibling;
}
MemoryStream ms = new MemoryStream();
dom.Save(ms);
ms.Position = 0;
return ms;
}
}
Next we create a class that will be able to use as an attribute
public class CompressionExtensionAttribute : System.Web.Services.Protocols.SoapExtensionAttribute {
private int _Priority;
// Override the base class properties
public override Type ExtensionType {
get { return typeof(CompressionExtension); }
}
public override int Priority {
get {
return _Priority;
}
set {
_Priority = value;
}
}
}
This approach involves updating the reference.cs manually. We are going to extend this in order that if we choose update webreference in Visual studion the attribute is added immediately to the proxy class. (For more detail goto: http://msdn2.microsoft.com/en-us/library/x4s9z3yc.aspx)
