TL;DR: Produce HAR from HttpClient in .NET
As at 2020-06-20, this project is extremely immature and not ready for any kind of use.
HAR is an archive format for HTTP traffic.
HAR is specified by the creator; it appears the W3C were planning to standardise it but decided not to, for whatever reason.
DO NOT USE
This document was never published by the W3C Web Performance Working GRoup and has been abandonned.
-- W3C; typos sic
This project treats the creator's online viewer as the authoritative validator.
Seems there is no "dead-simple" way of logging your application's HTTP traffic in .NET. Let's make one!
HttpMessageHandler is the intended means of injecting your own code into an HTTP request pipeline.
We aim to create an implementation of HttpMessageHandler which will log all through traffic, then
produce a HAR on demand.
It appears there are lots of HAR features that cannot be produced:
- pages doesn't exist as a concept
- timings breakdown, e.g. DNS, Connection, may not be visible to .NET client code
- connection identifiers may not be visible to .NET client code
- remote IP address may not be visible to .NET client code
- detail of the HTTP traffic "on the wire" is not visible to .NET client code (for example, the raw HTTP headers)
Further, there may be unavoidable performance and behaviour issues when using something like this:
- recording and serialising data as it passes through, without impacting performance of the consumer, may be a challenge
- the HAR message handler should be totally transparent, which may require reimplementing certain behaviour of the lower-level handlers
However, there is some value (at least to the author!) in producing a simple log of incoming and outgoing request data.