[8.x] Adds new RequestSent and ResponseReceived events to the HTTP Client

[lukeraymonddowning]

Hey guys,

This PR adds two new events, RequestSent and ResponseReceived, which are dispatched by the Http Client.

RequestSent

The RequestSent event is fired when any request is made when calling any of the following Http Client methods: 'get', 'head', 'post', 'put' and 'delete'. It receives the HTTP method, URL, and any sent options.

ResponseReceived

The ResponseReceived event is fired when a successful response is returned from the Http Client. It receives the Response instance.

What are the benefits?

These two events allow a 3rd party package to listen for and react to HTTP Client requests. I can see it being used for debugging, logging, performance monitoring, service downtime analysis and more.

I decided to contribute this when I went to create a PR for the spatie/laravel-ray package to allow monitoring of Http Client requests only to realise there wasn't a way to do so.

As always, thank you very much for all the hard work and for considering my PR.

Regards,
Luke

[taylorotwell]

Renamed to RequestSending (it is dispatched slightly before the request is actually sent), and moved its location to sendRequest method in case of promise usage. Otherwise, the event would have fired before the request was actually sending, which could have been confusing.

Thoughts?

[GrahamCampbell]

Why not include the request object in the first event?

[taylorotwell]

I agree having the full Illuminate\Http\Client\Request object would be useful in both events to be honest.

[lukeraymonddowning]

@taylorotwell agreed. Also agreed on the received event having the response object. I'll refactor when I'm back at my keyboard.

[lukeraymonddowning]

Okay @taylorotwell @GrahamCampbell, I've moved the firing of the RequestSending event to a beforeSendingCallback so that we can include the Request object.

I've also made the ResponseReceived event accept the Request too, so that you have both the request and response in that event. I've done this by setting the request in a property on the PendingRequest, which seemed the cleanest way to achieve this. Can you see any issues with that approach, or does that seem good to you?

[lukeraymonddowning]

Also @taylorotwell, completely understand if not (because seeing 'Request' as the first word makes sense in one way), but would it be worth considering SendingRequest as the event name, just so that it reads better as a phrase? Not precious, but thought it was worth raising as a question.