\Dewdrop\Fields\HelperSelectCallback

Allow users to modify a listing's Select using a callback. Can be useful if you don't need all the stock filtering and sorting logic for your specific case.

Helpers do this by enabling your to set custom callbacks for a field. In cases where a custom callback has not been assigned, helpers may attempt to automatically create a callback, using information in the field (e.g. the type of a database-related field).

For all helpers, you can assign custom callbacks globally or on a per-instance basis. Here's an example of defining a custom callback globally for a field:

$field->assignHelperCallback(
    'NameOfHelperToCustomize',
    function ($helper) {
        // Any custom logic you'd like to perform for this field.
    }
);

In the above example, "NameOfHelperToCustomize" is the name of the helper as defined in the helper's $name class property. This string is case insensitive.

To defined a custom callback on a per-instance basis for a helper, you can do the following:

$helper->assign(
    'my_model:field_id',
    function ($helper) {
        // Any custom logic you'd like to perform for this field.
    }
);

If you'd like to decorate an existing callback with additional logic, that's possible using the getFieldAssignment() method:

$field->assignHelperCallback(
    'NameOfHelperToCustomize',
    function ($helper) {
        return '' . call_user_func($helper->getFieldAssignment($field), $helper) . '';
    }
);

When a per-instance callback is assigned, that overrides any global or fallback callbacks. So, you can have an application-wide default (e.g. in a model) behavior for a field that is superseded in specific cases by adding a per-instance callback assignment for the field (e.g. in a view script).

Summary

Methods
Properties
Constants
matchesName()
assign()
getFieldAssignment()
hasValidName()
detectCallableForField()
setName()
setCallback()
setPrefix()
getPrefix()
modifySelect()
No public properties found
No constants found
wrapCallable()
$name
$prefix
$callback
N/A
No private methods found
$assignments
N/A

Properties

$name

$name : string

The name for this custom callback. Unlike others, this is defined at runtime for callback modifiers, not in the code.

Type

string

$prefix

$prefix : string

The prefix used by the listing.

Type

string

$callback

$callback : callable

The callback to call when applying the modifier.

Type

callable

$assignments

$assignments : array

Any per-instance callback assignments for this helper. This array will have field IDs as the keys and callables as the values.

Type

array

Methods

matchesName()

matchesName(string  $name) : boolean

Check to see if the supplied input matches this helper's name (case-insensitive).

Parameters

string $name

Returns

boolean

assign()

assign(mixed  $assignments, callable  $callable = null) : \Dewdrop\Fields\Helper\HelperAbstract

Assign one more custom per-instance callbacks for this helper. If the $arguments param is an array, this method expects that the keys will be field IDs and the values will be callables, assigning custom callbacks for multiple fields in one call. If, however, $assignments is a string or a FieldInterface object, a single custom callback assignment will be made.

Parameters

mixed $assignments
callable $callable

Returns

\Dewdrop\Fields\Helper\HelperAbstract

getFieldAssignment()

getFieldAssignment(\Dewdrop\Fields\FieldInterface  $field) : callable

Get the callback that will be used for the given FieldInterface object.

Parameters

\Dewdrop\Fields\FieldInterface $field

Throws

\Dewdrop\Fields\Exception\HelperCallableNotAvailableForField

Returns

callable

hasValidName()

hasValidName() : boolean

Ensure the helper has a valid $name value. If not, throw an exception.

All helpers must have a name defined so that global custom callbacks can be added to fields.

Throws

\Dewdrop\Fields\Exception\HelperMustHaveName

Returns

boolean

detectCallableForField()

detectCallableForField(\Dewdrop\Fields\FieldInterface  $field) : boolean|mixed

No per-field callbacks in this case, really.

If no callback candidate is found, just return false from this method, which will be detected by getFieldAssignment(), causing execution to halt.

Parameters

\Dewdrop\Fields\FieldInterface $field

Returns

boolean|mixed

setName()

setName(  $name) : $this

Set the name for this modifier. Primarily useful if you want to retrieve the modifier from the listing after initially registering it.

Parameters

$name

Returns

$this

setCallback()

setCallback(callable  $callback) : $this

Set the callback you'd like to use to modify the listing's Select object.

Parameters

callable $callback

Returns

$this

setPrefix()

setPrefix(string  $prefix) : $this

Set the param prefix used by the listing. Useful if you need to use your custom modifier with multiple listings.

Parameters

string $prefix

Returns

$this

getPrefix()

getPrefix() : string

Get the prefix for the listing parameters.

Returns

string

modifySelect()

modifySelect(\Dewdrop\Fields  $fields, \Dewdrop\Db\Select  $select) : \Dewdrop\Db\Select|mixed

Note that when we call this particular modifier's callback, we only pass the Select object, not the fields or any other information. If you need access to that info, arrange for it in the code where you're defining the callback in the first place. The common case only needs the Select itself in the callback, so we optimize for that.

Parameters

\Dewdrop\Fields $fields
\Dewdrop\Db\Select $select

Throws

\Dewdrop\Exception

Returns

\Dewdrop\Db\Select|mixed

wrapCallable()

wrapCallable(callable  $callable, \Dewdrop\Fields\FieldInterface  $field = null) : callable

Wrap a field's callback to ensure that a reference to the helper is always supplied as the first argument to the callback.

Parameters

callable $callable
\Dewdrop\Fields\FieldInterface $field

Returns

callable