Wcf Silverlight Compression Gzip

The Easiest Way to Add Compression to WCF in Silverlight

When developing applications with Silverlight that access WCF web services, developers often encounter the challenge of handling large amounts of XML data. This can lead to inefficient bandwidth usage as the uncompressed data transmitted over the network can be substantially larger than necessary. If you’re facing this problem and looking for a straightforward solution to add compression to your WCF service responses, you’re in the right place!

In this blog post, we will explore how to enable gzip compression on IIS7 to improve the performance of your Silverlight applications without needing intricate code changes.

Understanding the Problem

The Context

You may be operating a Silverlight application that relies on WCF services via basicHttpBinding. When the service returns a significant amount of XML data, the resulting payload can be quite hefty, leading to wasted bandwidth. For example, through experimentation, one developer found that the response size could be reduced by a factor of five if gzip compression was applied.

When making requests, your application sends the header "Accept-Encoding: gzip, deflate", indicating that it can process compressed responses. However, without the appropriate server configuration for compression, your application will still receive large, uncompressed data.

Why Compression Matters

  • Improved Performance: By reducing the size of the data transmitted over the network, compression decreases load times.
  • Reduced Bandwidth Usage: Using less bandwidth can save costs and ensure faster responses, especially for users with slow internet connections.

The Solution: Enabling Dynamic Compression in IIS7

Instead of diving into complex code solutions or relying on frameworks not supported in Silverlight, enabling IIS7’s built-in dynamic compression is the easiest avenue to achieve the desired performance improvement. Here’s how you can do it:

Step-by-Step Guide

  1. Access IIS7 Settings: Open Internet Information Services (IIS) Manager on your server.

  2. Select Your Application: In the Connections pane, select the site or application for which you want to enable compression.

  3. Open Compression Settings: In the Features View, look for the “Compression” icon and double-click it.

  4. Enable Dynamic Compression: Check the box for “Enable dynamic content compression,” which allows server responses to be compressed on-the-fly.

  5. Restart IIS: After making changes, restart your IIS server to ensure the new settings take effect.

Testing Compression

Once dynamic compression is enabled, you can verify its functionality using HTTP traffic monitoring tools like Fiddler:

  • Use Fiddler: Monitor the traffic for your WCF service calls. You should see responses being transmitted with Content-Encoding: gzip indicating that compression is indeed working.

Avoiding Common Pitfalls

  • Additional Configuration: There’s no need for extra code or libraries like System.IO.Compression, which are not available in Silverlight. Rely exclusively on IIS for this solution.
  • Browser Plugins: Some developer tools may not accurately reflect the compression in their results. This is why using Fiddler or similar tools is crucial for a true representation of your traffic.

Conclusion

Enabling gzip compression for your WCF services in a Silverlight application is a straightforward process when leveraging IIS7. By simply turning on dynamic compression settings, you can greatly improve your application’s efficiency without additional coding overhead. This solution not only enhances performance but also optimizes your resource utilization, making for a better user experience.

If you have more questions about WCF services, Silverlight, or IIS configurations, feel free to reach out in the comments below!