Ability to output in different formats

[5zymon]

This update is bigger in compare to the previous one, so you may want to take a longer look before merging :-).

I needed output to CSV file so I modified google shopping container - which I think was prepared for functionality like this in future. I've separated feed class into formats classes one for XML and one for CSV. Core functionality stayed the same, I am using this library in other module and without making any changes in the module, it generates same XML output as before, so I assume all is good here I didn't break anything. But now when you enter 'csv' in the container, instead of null, you'll get CSV as an output.

It also requires new lib league/csv, which requires php 7 so I had to move the require in composer.json up from php 5.3.0 (which isn't that bad anyway I think ;-)).

[lukesnowden]

You’ll have to leave me with this one, big commit. When I get a free hour I’ll take a look over it

[5zymon]

No rush and no worries! 90% of this is your code moved around so it can be shared for different formats :-).

[lukesnowden]

Sat in pub having a look over it looks good but I’ll wait until I’m back at my Mac to test t👍

[Fredyy90]

any updates on this old pull request? i would really like to see an output option to get facebook compatible csv

[lukesnowden]

Have you pulled this PR down and tested it works?

[Fredyy90]

no haven't checked it, I think it might need fundamental rebasing, as its over 3 years behind the current versions.
i might take a look at it later, we currently run in the issue, that our feed is multiple gigabytes big and the xml overhead is an issue we would like to avoid. so an output option to get facebook csv would be exactly what we need.

[lukesnowden]

If you pull it down and it all works as expected let me know and I'll merge it in as a new major version release

[Fredyy90]

I forked @5zymon repo and tested it with my current setup.

I didn't rebase it yet to also get all last 3 years changes, since I don't know how to "claim" this pr or how to fork a repo and rebase it on another repo.

But @5zymon PR works as expected, you need to set the format you want first, when configuring your feed. If you don't want to use the default format (XML).
GoogleShopping::$container = \LukeSnowden\GoogleShoppingFeed\Formats::CSV;

After setting the format, everything else works as before, you also have to run GoogleShopping::asRss(false); to get the output. This is maybe the only "unlogical" thing in the PR as the function will no longer output RSS when changing the format before.

But changing the name of the function will also result in a breaking change. Potentially, we can rename the output function to export() or output() and keep a second function called asRSS() for backward compatibility, that just calls the new renamed version.

    public function asRss($output = false)
    {
        return $this->output($output);
    }