Batch Requests

[jorgeborges]

Continues the work from #83 by @alberto-bottarini.

This PR allows you to batching multiple hits in a single request using /batch endpoint.

It adds some new methods:

• enqueue{$hitType}() (using __call magic method)
• sendEnqueuedHits()
• emptyQueue()

Here's an example that sends two hits.

$analytics = new Analytics(false, false);

$analytics
    ->setProtocolVersion('1')
    ->setTrackingId('UA-xxxxxx-x')
    ->setClientId('xxxxxx.xxxxxx');    

foreach(range(0, 19) as $i) {
    $analytics = $analytics
        ->setDocumentPath("/mypage$i")
        ->enqueuePageview(); //enqueue url without pushing
}

$analytics->sendEnqueuedHits(); //push 20 pageviews in a single request and empty queue

The queue is emptied when the hits are sent, but it can also be empty manually with emptyQueue method.

$analytics = new Analytics(false, false);

$analytics
    ->setProtocolVersion('1')
    ->setTrackingId('UA-xxxxxx-x')
    ->setClientId('xxxxxx.xxxxxx');    

foreach(range(0, 5) as $i) {
    $analytics = $analytics
        ->setDocumentPath("/mypage$i")
        ->enqueuePageview(); //enqueue url without pushing
}

$analytics->emptyQueue(); // empty queue, allows to enqueue 20 hits again

foreach(range(1, 20) as $i) {
    $analytics = $analytics
        ->setDocumentPath("/mypage$i")
        ->enqueuePageview(); //enqueue url without pushing
}

$analytics->sendEnqueuedHits(); //push 20 pageviews in a single request

[coveralls]

Coverage remained the same at 100.0% when pulling af8bdc5631abaefa90de6c8c05b8eb0c520ebfae on feature/batch-requests into 0797dcc1cf2cfee9cd0353e5615c1186cc8a721e on master.

[jorgeborges]

hey @alberto-bottarini, I'm done with the changes required for this to be merged.

Take notice that your commits are also in this PR. Changes that I made:

• I had to revert to PHPUnit 4.7 because version 4.8 requires PHP 7.1 onwards and this library still supports PHP 5.5, 5.6 and 7.0 (CI tests in TravisCI were failing), dropping support for a major PHP version should be done in the next major release v3 (this lib is currently v2).
• I added the change you suggested that the lib empties the queue after the hits are sent to the batch endpoint.

Besides that, I also did the following:

• Refactored code in HttpClient that was being duplicated in the previous PR, moved the duplicated code to a private method.
• Added missing unit tests that were causing the test coverage to go down by 2%, preventing this from being merged (test coverage cannot go down).
• Added documentation on how to use the batch hit feature in the README (would be good if you can have a read).

Everything else is working as in your PR.

If you are OK with these changes, I can merge right away and make a new release. Is this OK with you?

[alberto-bottarini]

It's ok for me! Thanks a lot