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WSE and Plumbwork Orange
Mono 1.0 Hits RTM
Mono Roadmap Updated
Enforcing Xml Schema Validation
Consolidating some WSE efforts
WSE: Compression Filters
WSE: Compression, Security and Performance
TweakDotNet v0.2 Released
WSE and Attributes Evolved

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# Saturday, July 10, 2004
WSE and Plumbwork Orange
Saturday, July 10, 2004 8:31:29 AM UTC ( WSE )

For those of you using the Microsoft Web Services Enhancements 2.0 or my WSE “WS-Compression” filters it is time to look at some very interesting developments in that area.

Over the last few months, I have been participation in a GotDotNet project aimed to provide free implementations of important WSE based infrastructure. You will find everything from WS-protocol implementations to helper classes, examples of WSE extensibility features and prototypes if some interesting ideas

With strong WSE personalities like John Bristowe and Christian Weyer heading up the project this is definitely something that carries a lot of potential.

Drop by the project workspace at GotDotNet!

Comments [0] | | # 
# Thursday, July 1, 2004
Mono 1.0 Hits RTM
Thursday, July 1, 2004 8:57:49 AM UTC ( General | Mono )

Mono, an Open Source implementation of .Net finally makes it to its first release, the big version 1.0. After years of development it’s nice to see the progress they’ve made.

Congratulations to the team.

Comments [0] | | # 
# Wednesday, April 28, 2004
Mono Roadmap Updated
Wednesday, April 28, 2004 6:56:42 PM UTC ( Mono )

The mono team has put up an updated roadmap for the mono project.

Beta 1: May 4th - Feature Complete

Beta 2: June 1st

Mono 1.0: June 30th

I guess this means that if they stay on track we will have a fairly stable multiplatform CLR and BCL this summer. The mono platform still lacks several critical enterprise features, but it is interesting to see what they have accomplished so far.

Comments [0] | | # 
# Sunday, April 25, 2004
Enforcing Xml Schema Validation
Sunday, April 25, 2004 3:26:08 PM UTC ( General )

Validating xml documents is one of the more common tasks when building extensibility points, integration infrastructure or enabling configuration support. The .Net Framework provides a type called XmlValidatingReader to help you with this task. There are however a few pitfalls you should be aware of if you want to be certain that an xml instance conforms to the provided xml schema.

Always Define a Validation Event Handler

The xml validation system uses severity levels to indicate the level of validation failure. There are two severity levels available; namely XmlSeverityType.Error and XmlSeverityType.Warning. The interesting thing is that unless you specify your own validation handler only the severity level of XmlSeverityType.Error will cause an exception to be thrown; all warnings are ignored.

This may not seem like a big issue until you realize that “missing schema for provided type” is a warning and not an error. Therefore, unless you have a schema loaded for the xml instance namespace, anything goes.

When you provide your own validation handler, you can intercept both severity levels and act accordingly. A simple default could be to throw the exception provided within the ValidationEventArgs parameter, as you will see in the sample below.

Always Specify a ValidationType

The default ValidationType is ValidationType.Auto, which means that unless you have provided a schema for the instance namespace, it will assume ValidationType.None and no validation takes place.

If you are using Xml Schemas, you should set this to ValidationType.Schema.

In Conclusion

The common theme here is that vanilla validation only works if you happen to have the same namespace in your xml instance and xml schema documents. Unless your application explicitly checks the namespace of the xml instances it processes, you could easily submit whatever xml document you wanted as long as it uses a different namespace than what the schema expects.

You will find a code snippet below that incorporates this advice, and hopefully gives you some ideas on how to address these issues in you code.

Code Snippet

static void ValidationHandler(object o, ValidationEventArgs args)
{
 throw args.Exception;
}

static void Validate(XmlReader reader, XmlSchema schema)
{
 XmlValidatingReader validatingReader = new XmlValidatingReader(reader);
 validatingReader.ValidationEventHandler += new ValidationEventHandler(ValidationHandler);
 validatingReader.Schemas.Add(schema);
 validatingReader.ValidationType = ValidationType.Schema;
 while (validatingReader.Read());
 validatingReader.Close();
}
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# Friday, March 5, 2004
Consolidating some WSE efforts
Friday, March 5, 2004 10:54:47 PM UTC ( WSE )

There seems to be quite a few WSE extension projects out there. Some of them implement custom transports, some implement custom filters and some implement public specifications.

Perhaps we should consolidate our efforts and set up a project on a public server like the GotDotNet workspaces. Create a Genghis for WSE if you will.

Just a thought ;)

Comments [0] | | # 
# Wednesday, March 3, 2004
WSE: Compression Filters
Wednesday, March 3, 2004 7:08:59 PM UTC ( Tools | WSE )

Matthew Lynn asked for the WSE compression filter code, and here it is.

My colleague Martin Valland and I wrote this code based on an idea we had for a compression specification for web services. This implementation as well as the SOAP extensions it relies upon is proprietary. As far as I know there is currently no publicly available specification that addresses this particular subject.

The code relies upon #ziplib for the compression algorithms.

This is a prototype implementation and it comes without warranty of any kind.

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# Sunday, February 15, 2004
WSE: Compression, Security and Performance
Sunday, February 15, 2004 8:16:33 PM UTC ( Security | WSE )

We have been doing a lot of WSE testing at work while developing our new integration infrastructure. As a part of this project we have built a filter for message level compression in WSE.

One of the interesting things we found out while performance testing the solution was the speed increase resulting from message compression. The system we are building transfers sensitive data across the internet and we are using X509 certificates for integrity and confidentiality. Naturally, we had to apply the compression before the security mechanisms were invoked, as compressing encrypted data isn’t efficient at all. However compressing xml data is very efficient; often resulting in 80% smaller message bodies.

Having a smaller message body means that the encryption and signing process has a lot less data to deal with, and this reduced the processing time significantly. We did of course consider that the smaller payload would increase transfer performance, but on our test-setup this was not a issue.

The bottom line is that our initial testing shows that the gzip compression algorithm is faster than the encryption and signing process used by WSE. This came as a surprise to us as signing involves hashing and the encryption implementation uses a block cipher, and neither of these should have performance issues with large amounts of data; at least not compared to a compression algorithm!

This topic requires a bit more research before I can reach a conclusion, but so far I am a bit surprised. On the other hand, the results we are seeing could be related to some other part of the process like the normalization algorithm.

Having fun ;)

Comments [0] | | # 
TweakDotNet v0.2 Released
Sunday, February 15, 2004 7:40:26 PM UTC ( Tools )

I have fixed some small issues with TweakDotNet and released a new version. TweakDotNet is a small and simple program that lets you choose the default source control provider as well as edit the assembly folders used by Visual Studio.Net.

TweakDotNet v0.2 is available for download at its GotDotNet workspace.

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# Tuesday, February 10, 2004
WSE and Attributes Evolved
Tuesday, February 10, 2004 5:48:26 PM UTC ( WSE )

Work continues on my little WSE project. Here is a more evolved piece of sample code...


[WebMethod]
[WseProfile("Default")]
[WseX509Security]
[WseCompression(CompressionMode.GZip)]
[WseMessageBodyValidator("MyMessage.xsd")]
public void MySecureMethod(int x, int y)
{
  ...
}
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