README

A PHP library for creating objects compatible with my form specification.

General structure

The FormStructure class consists of:

• A collection of FieldInterface objects
• An optional auto_focus value which indicate which field should be automatically focused

Each FieldInterface contains the BaseFieldAttributeInterface as well as any additional attribute interfaces necessary for the type of field.

Custom fields and attributes

While the library comes with various "built-in" fields, you can create your own. Custom fields must use the FieldInterface, which extends the BaseFieldAttributeInterface.

The library also comes with re-useable field attribute interfaces and traits, such as the NumberAttributeTrait. You can create custom field attributes, either following the existing attribute interfaces or implementing your own methods.

Attributes and JsonSerializable

The BaseFieldAttributeTrait contains a protected method, baseAttributesToArray, which is used by most of the other built-in traits in a protected toArray method. This method is called by the FieldTrait when creating a JSON representation of a field.

Your custom classes do not need to strictly follow this structure. You are free to implement a completely different structure, provided it follows the form specification.

Pre-populating custom fields

You may want to implement a field which pre-populates certain attribute properties. An example of how to do this can be found in the built-in BooleanField.

Set up an alias for the __construct method:

use FieldTrait, ChoiceAttributeTrait {
    FieldTrait::__construct as defaultConstruct;
}

Then, set up your custom constructor, remembering to call the aliased constructor method:

public function __construct(string $key)
{
    $this->defaultConstruct($key);

    $this
        ->addOption($this->createOption(true, 'Yes'))
        ->addOption($this->createOption(false, 'No'))
        //
    ;
}

Currencies and locales

The library will make use of the symfony/intl package (if installed) to pre-populate the options for the CurrencyField and validate values for methods in the CurrencyField and MoneyAttributeTrait classes.

It is not strictly necessary to install the package to make use of these fields.

Error responses

The FormErrors class is used to create a standard error response to invalid forms:

{
    "message": "There are form errors",
    "form": {
        "name": [
            "This field is required"
        ]
    }
}

The form property is optional if there are no issues with the form itself:

{
    "message": "You do not have permission to submit this form"
}

Exceptions

The library contains one custom exception, InvalidArgumentException, which is called when one of the arguments submitted to a class method is invalid for some reason. For example, submitting a negative number for a method which only accepts positive numbers.

This custom exception allows you to handle library exceptions separately if needed.

Version notes

1.0.0

• Initial library publication

Future plans

I have the same plans for this library as I do for my form specification.

If I learn about a smarter way to structure this class, I'll update the library. Much of this work is a learning experiment and I'd like to improve on my work as I learn more.