Use putenv() in InitialisationMiddleware

[ichaber]

This commit it based on changing the order of execution in InitialisationMiddleware.
It proposes to change the setting of the environment variables for http_proxy, https_proxy and NO_PROXY from Environment::setEnv() back to putenv() as it was in CWP1.

As described in the documentation of InitialisationMiddleware its main purpose is to configure the proxy so it is automatically picked up when calling curl in an apache context.
I'm aware of the multithreaded issue described in laravel/framework#7354, but considering that these variables should be present anyway, I don't consider that to be an issue in context of CWP. Maybe @tractorcow has some insights into that?

Otherwise the variables are redundant as SS_OUTBOUND_PROXY, SS_OUTBOUND_PROXY_PORT and NO_PROXY already exist.

[robbieaverill]

I assume the tests are failing since Environment::getEnv('http_proxy' has been called once already in the unit test class, so subsequent requests no longer read from getenv()

[ichaber]

Yeah, it looks like the testConfigureEgressProxyDomainExclusions fails on re-setting the environment, because it's not using the Environment class anymore. 🤔

[robbieaverill]

You could maybe putenv('https_...', '') in setUp() of that class to work around it

[ichaber]

That wouldn't actually resolve the issue. If we use Environment::setEnv() with a key, there will always be a key in static::$env and the getEnv will never fall through to the getenv() call.

[chillu]

Do we need to add this to the CWP upgrading guide?

[robbieaverill]

It's technically a regression - I think we'll retarget this at 2.0 and merge it up so future releases will configure the proxy automatically. For now though we have the External HTTP requests with proxy docs for configuring this, and our supported modules implement the proxy explicitly when using Guzzle for example.

@indygriffiths previously removed the mention of auto-configured cURL requests in silverstripe/cwp#171.

I'd like to get this in as soon as CWP 2.2.2 is released.