Cloudflare has announced the release of the source code for the h3i toolkit, which includes a command-line utility and a library of functions for low-level testing and debugging of server implementations of the HTTP/3 protocol. The utility can be used to assess the behavior of HTTP/3 servers, determine compliance with specifications, and test responses to exceptional situations. The utility code is written in Rust and is open-sourced under a BSD license.
The utility can be used as an HTTP/3 client, providing enhanced capabilities for complete control over the communication channel. For example, h3i allows you to send frames in any HTTP/3 stream and in any order, including both valid and invalid content. All actions are logged, which can later be used to replay the session.
The library included can be used to write automated tests that verify the correctness of HTTP/3 support during development. servers HTTP/3 and assess the performance of their systems and services, including when sending incorrect requests and making anomalous changes to data streams (for example, sending binary frames with headers not in the correct order or specifying a Content-Length header that does not match the actual data size).
Diagnosing HTTP/3 is complicated due to the complexity of the protocol, which uses the QUIC protocol based on UDP as transport and applies quite sophisticated mechanisms for flow control, operation parallelization, prioritization, connection multiplexing, bidirectional data transmission, and packaging of information, headers, settings, and commands into binary frames.
Source: opennet.ru
