httpVersion not captured correctly in HTTP Archive har file

[tunetheweb]

httpVersion is not captured correctly more often than not and seems to be blank for HTTP/1.1 requests and either ori or us:

I had a grep through the code and found this (and a similar one for response further down):

https://github.com/WPO-Foundation/webpagetest/blob/3afaeea71067efa0316786b79cae4de7d9724f8c/www/har/HttpArchiveGenerator.php#L227-L260

From my limited understanding it seems to to look for a header which has a colon (but not in first position) is a candidate for HTTP version and then grabs the 3 characters after HTTP.

While that may work in a HTTP/1.0 and HTTP/1.1 world (though even there seems flakey) it definitely won't work in a HTTP/2 which has pseudo headers which begin with a colon (so in position 0) such as :authority: (note the 3 characters after the 5 characters is ori) or :status: (note the 3 characters after the 5 characters is us:) and also only has a 1 character version number not 3.

It looks like the correct version number is in the _protocol column but don't think you can get a different value for request and response like I guess you could get in the pre-HTTP/2 world.