Allow for protocol schema in proxy configuration

[sadym-chromium]

Currently the "Valid values" of proxy configuration's httpProxy, sslProxy and socksProxy are host and optional port. This makes impossible scenarios of proxying HTTP requests via HTTPS proxy.

Consider allow scheme in proxy configuration's httpProxy, sslProxy and socksProxy valid values.

[whimboo]

You can specify a proxy as secure-proxy.example.com:443 so that there is no need to have to specify the schema. So I think this is all fine.

[sadym-chromium]

You can specify a proxy as secure-proxy.example.com:443 so that there is no need to have to specify the schema. So I think this is all fine.

I'm not sure if the specific port would automatically force to use the specific protocol, especially if it is a custom port like 12345.

[whimboo]

I've asked @jgraham as well why we didn't initially add a schema but we cannot remember.

So the interesting part is that no-one yet brought up an issue with a proxy regarding schema selection. Maybe that's really a niche thing that users have in place for their automation? Do you have an example where this is currently broken and needs to be fixed outside of a unit test for wpt?

If there is a use case we could definitely get a schema like property added, which probably should be optional so that we can keep backward compatibility.

[sadym-chromium]

Puppeteer allows for a string value in BrowserContextOptions. proxyServer. This string is equivalent of --proxy-server CLI argument, which allows for such scenarios:

Manual proxy settings can succinctly describe setups like:

• Use proxy http://foo:8080 for all requests
• Use proxy http://foo:8080 for all requests except those to a google.com subdomain.
• Use proxy http://foo:8080 for all https:// requests, and proxy socsk5://mysocks:90 for everything else

So Chrome and Puppeteer supports proxy settings like http=https://foo:443;socks=socks5://mysocks:1080.

[sadym-chromium]

@whimboo @jgraham here is the proposed solution: #1922

[css-meeting-bot]

The Browser Testing and Tools Working Group just discussed Allow for specifying schema in "proxy".

The full IRC log of that discussion

<tidoust> Topic: Allow for specifying schema in "proxy"
<tidoust> github: https://github.com//issues/1920
<tidoust> sadym: We don't support a core feature supported in Chrome. You can proxy http over http, ssl over ssl, or socks over specific versions. But in Chrome, we can proxy http over https for example. That makes me propose a change in the API for the schema which allows schema to be provided for the proxy value.
<tidoust> ... I wanted to get feedback.
<jgraham> q?
<tidoust> jgraham: If it's supported in Gecko, it seems reasonable to be in WebDriver. It may be reasonable to have it in WebDriver even if it's not, provided that we can return something like "not supported".
<tidoust> sadym: It's kind of a breaking change due to where you specify the schema, but we can sort that out offline.