Support DSN in Client constructor for config argument (#1640)

[alamirault]

This PR allow to pass DSN to the Elastica\Client constructor as discussed in #1640 .

For example: $client = new Client('https://user:[email protected]:9200?persistent=false&retryOnConflict=2');

I have just a doubt about url config parameter. Should I build it from transport, host, port and path ? Or it works when these args are filled ?

Another question: Is there a doc to update ? Elastica.io appears to be outdated.

[ruflin]

This looks really good and thanks for adding all the tests.

For url: What you mean by "it works when these args are filled"?

For the docs: Use the phpdocs as extensive as possible. Elastica.io didn't get all the love it should get recently, but it is the place for the docs which don't fit the source code.

[alamirault]

I reworked my PR. Now the client configuration is exported in new class. It avoid code duplication.
I also allow any extra option (removed hardcoded part)

[ruflin]

I like the change to use a separate class for the config object. I'm trying to poke holes into this change to see what side effects it could have. So far the only thing I could think of is that something that inherits the client could mess around with _config but even this should be fine as it can still be an array.

It seems everything should continue to works as before?

[alamirault]

I think is only side effect. Indeed everything works without any changes.

I also would like deprecate setConfig,getConfig,setConfigValue,getConfigValue and add a ClientConfiguration getter in Client. WDYT ?

[ruflin]

@alamirault Your proposal SGTM. I already merged the PR as I think these additional changes / deprecations should go into a separate PR. I hope you are ok with that?

[alamirault]

I agree. I will make another PR when I have time.