feat(corporate proxy #1188): support in verifier

[zac-poe-vg]

Add native support of HTTPS_PROXY and HTTP_PROXY for verifier for #1188

This change adds two pieces of behavior:

• The verifier's 2 step parse body behavior now uses a proxy request buffer (instead of the 'proxyReq' rewrite behavior) to ensure the request stream is accessible for intermediary agent behavior
• The verifier natively supports HTTP_PROXY/HTTPS_PROXY config and assigns a proxy http Agent where those values are present

This results in out-of-the-box support for corporate proxies in the js verifier

[zac-poe-vg]

this is one piece of behavior that did go away - I didn't see any tests around content length header specifically, so I thought this might have just been a best practice with the rewrite that was used here

if this creates a gap, let me know and I can see about doing something similar with the proxy request options

[mefellows]

Thanks. I believe this was required given the way the previous body was parsed and then re-written into the subsequent request. Given that you're now using the buffer option on the HttpProxy itself, perhaps it's no longer needed.

The main behaviour we'll need to check is if we can intercept and modify the incoming body using the hooks/filters. I'll pull this in locally and do some testing, I don't think it's an area with great test coverage if I'm honest.

[mefellows]

This looks great. i'm going to test locally with a few scenarios and if they work, will bring this in asap!

[mefellows]

Thanks. I believe this was required given the way the previous body was parsed and then re-written into the subsequent request. Given that you're now using the buffer option on the HttpProxy itself, perhaps it's no longer needed.

The main behaviour we'll need to check is if we can intercept and modify the incoming body using the hooks/filters. I'll pull this in locally and do some testing, I don't think it's an area with great test coverage if I'm honest.