FiddlerCore and Brotli compression

Recently, a developer asked me how to enable Brotli content-compression support in FiddlerCore applications, so that APIs like oSession.GetResponseBodyAsString() work properly when the entity body has been compressed using brotli. Right now, support requires two steps: Put brotli.exe (installed by Fiddler or off Github) into a Tools subfolder of the folder containing your application’s executable. Ensure that theContinue reading “FiddlerCore and Brotli compression”

Working with “Big Data” in .NET

For simplicity (and because I didn’t know any better at the time), Fiddler uses plain public byte[] array fields to represent the request and response bodies. This makes working with the body data trivial for authors of extensions and FiddlerScript, but it also creates significant shortcomings. Using fields rather than properties improves performance in some scenarios,Continue reading “Working with “Big Data” in .NET”

Finding Image Bloat In Binary Files

I’ve previously talked about using PNGDistill to optimize batches of images, but in today’s quick post, I’d like to show how you can use the tool to check whether images in your software binaries are well optimized. For instance, consider Chrome. Chrome uses a lot of PNGs, all mashed together a single resources.pak file. Tip:Continue reading “Finding Image Bloat In Binary Files”

Compression Context

ZIP is a great format—it’s extremely broadly deployed, relatively simple, and supports a wide variety of use-cases pretty well. ZIP is the underlying format beneath Java (.jar) Archives, Office (docx/xlsx/pptx) files, Fiddler (.saz) Session Archive ZIP files, and many more. Even though some features (Unicode filenames, AES encryption, advanced compression engines) aren’t supported by allContinue reading “Compression Context”

Automatically Evaluating Compressibility

Fiddler’s Transformer tab has long been a simple way to examine the use of HTTP compression of web assets, especially as new compression engines (like Zopfli) and compression formats (like Brotli) arose. However, the one-Session-at-a-time design of the Transformer tab means it is cumbersome to use to evaluate the compressibility of an entire page orContinue reading “Automatically Evaluating Compressibility”