[6.x] Add boolean($key) method to Request

[LasseRafn]

This PR introduces a new helper method to the Illuminate\Http\Request: boolean($key) which takes input using the input() method and filters it through filter_var and FILTER_VALIDATE_BOOLEAN

Brief about FILTER_VALIDATE_BOOLEAN from php.net:

Returns TRUE for "1", "true", "on" and "yes". Returns FALSE otherwise.

// Before
$availableForHire = filter_var(Request::boolean('available_for_hire'), FILTER_VALIDATE_BOOLEAN);

// After
$availableForHire = Request::boolean('available_for_hire');

I set the default to be false so than an undefined variable (eg unchecked checkbox) would act as false.

Unsure how everyone feels about this and the naming of it though.

(edit: removed references to FILTER_NULL_ON_FAILURE as it was removed from the code)

[taylorotwell]

What made you want to use FILTER_NULL_ON_FAILURE?

[LasseRafn]

Honestly I did not want to at first, but figured if the value is something entirely different than a Boolean (“hello world”) then it probably shouldn’t be one? But I don’t know.

Personally I never use it myself but thought I’d hear screams if not used, haha.

— edit —

So I am 100% up for removing that!

[taylorotwell]

Personally I would remove it. It adds a third value that this function can return which gives the user more situations to consider, etc.

[LasseRafn]

Very good point! I’ll modify

[taylorotwell]

Could you send us a PR to the laravel/docs repository (6.x branch). Thanks.

[LasseRafn]

Thanks! Let me know if wording etc. should be improved

[shez1983]

this is a general comment - ignore if not suitable - in another PR the tester used a php annotation

/*
* @dataProvider validUuidList 
*/

wheras here its being done 5/6 times in the test - is there concern for consistency or it doesnt matter?

[sharifzadesina]

What is the point of this while we don't allow string values like "on"/"off" inside validation?
https://github.com/laravel/framework/blob/6.x/src/Illuminate/Validation/Concerns/ValidatesAttributes.php#L353-L358
Also, why adding too many methods in request? While people can use "sanitizer" libraries?
https://github.com/Waavi/Sanitizer

[LasseRafn]

Simplify the code I guess? But yes I agree that would be nice too

[sharifzadesina]

@LasseRafn How this simplifies the code while the validator doesn't accept "false", "true", "on", "off", string values? also, in PHP, values like, 0, 1, "0", "1", can be considered as booleans, which are already accepted by the validator.
Anyways, this PR is merged, but I think, this just causes more confusion.

[LasseRafn]

It simplifies getting values as a Boolean. Instead of doing filter_var($value, FILTER_VALIDATE_BOOLEAN) on the request value