Form Controller

The Backend\Behaviors\FormController class is a controller behavior used for easily adding form functionality to a backend page. The behavior provides three pages called Create, Update and Preview. The Preview page is a read-only version of the Update page. When you use the form behavior you don't need to define the create, update and preview actions in the controller - the behavior does it for you. However you should provide the corresponding view files.

Form behavior depends on form field definitions and a model class. In order to use the form behavior you should add it to the $implement property of the controller class. Also, the $formConfig class property should be defined and its value should refer to the YAML file used for configuring the behavior properties.

namespace Acme\Blog\Controllers;

class Categories extends \Backend\Classes\Controller
{
    public $implement = [
        \Backend\Behaviors\FormController::class
    ];

    public $formConfig = 'config_form.yaml';
}

# Configuring the Form Behavior

The configuration file referred in the $formConfig property is defined in YAML format. The file should be placed into the controller's view directory. Below is an example of a typical form behavior configuration file.

# config_form.yaml
name: Blog Category
form: $/acme/blog/models/post/fields.yaml
modelClass: Acme\Blog\Post

create:
    title: New Blog Post

update:
    title: Edit Blog Post

preview:
    title: View Blog Post

The following properties are required in the form configuration file.

The configuration properties listed below are optional. Define them if you want the form behavior to support the Create, Update or Preview pages.

# Create Page

To support the Create page add the following configuration to the YAML file.

create:
    title: New Blog Post
    redirect: acme/blog/posts/update/:id
    redirectClose: acme/blog/posts

The following properties are supported for the Create page.

# Update Page

To support the Update page add the following configuration to the YAML file.

update:
    title: Edit Blog Post
    redirect: acme/blog/posts

The following properties are supported for the Update page.

# Preview Page

To support the Preview page add the following configuration to the YAML file:

preview:
    title: View Blog Post

The following properties are supported for the Preview page.

# Custom Messages

Specify the customMessages property to override the default messages used by the Form Controller. The values can be plain text or can refer to a localization string.

customMessages:
    notFound: Did not find the thing
    flashCreate: New thing created
    flashUpdate: Updated that thing
    flashDelete: Thing is gone

You may also modify messages in the context of the form being displayed. The following will override the notFound message for the update context only.

update:
    customMessages:
        notFound: Nothing found when updating

The following messages are available to override as custom messages.

# Restricting with Permissions

Specify the permissions property to apply restrictions to actions provided by the Form Controller. Use permission values that the current backend user must have in order for the field to be used. Supports either a string for a single permission or an array of permissions of which only one is needed to grant access.

permissions:
    modelCreate: admins.manage.create
    modelDelete: admins.manage.delete

The following properties are available to override as required permissions.

# Defining Form Fields

Form fields are defined with the YAML file. The form fields configuration is used by the form behavior for creating the form controls and binding them to the model fields.

The file is placed to a subdirectory of the models directory of a plugin. The subdirectory name matches the model class name written in lowercase. The file name doesn't matter, but fields.yaml and form_fields.yaml are common names. Example form fields file location:

├── plugins
|   └── acme
|       └── blog
|           └── models
|               ├── post  ← Config Directory
|               |   └── fields.yaml  ← Config File
|               └── Post.php  ← Model Class

Fields can be placed in three areas, the outside area, primary tabs or secondary tabs. The next example shows the typical contents of a form fields definition file.

# fields.yaml
fields:
    blog_title:
        label: Blog Title
        description: The title for this blog

    published_at:
        label: Published date
        description: When this blog post was published
        type: datepicker

    # [...]

tabs:
    fields:
        # [...]

secondaryTabs:
    fields:
        # [...]

# Form Views

For each page your form supports Create, Update and Preview you should provide a view file with the corresponding name - create.htm, update.htm and preview.htm.

The form behavior adds two methods to the controller class: formRender and formRenderPreview. These methods render the form controls configured with the YAML file described above.

# Create View

The create.htm view represents the Create page that allows users to create new records. A typical Create page contains breadcrumbs, the form itself, and the form buttons. The data-request attribute should refer to the onSave AJAX handler provided by the form behavior. Below is a contents of the typical create.htm form.

<?= Form::open(['class'=>'layout']) ?>

    <div class="layout-row">
        <?= $this->formRender() ?>
    </div>

    <div class="form-buttons">
        <div class="loading-indicator-container">
            <button
                type="button"
                data-request="onSave"
                data-request-data="{ close: true }"
                data-hotkey="ctrl+enter, cmd+enter"
                data-load-indicator="Creating Category..."
                class="btn btn-default">
                Create and Close
            </button>
            <span class="btn-text">
                or <a href="<?= Backend::url('acme/blog/categories') ?>">Cancel</a>
            </span>
        </div>
    </div>

<?= Form::close() ?>

To track unsaved changes and display a warning when navigating away from the form, include the data-change-monitor attribute on the form opening tag.

<?= Form::open(['class' => 'layout', 'data-change-monitor' => true]) ?>

# Update View

The update.htm view represents the Update page that allows users to update or delete existing records. A typical Update page contains breadcrumbs, the form itself, and the form buttons. The Update page is very similar to the Create page, but usually has the Delete button. The data-request attribute should refer to the onSave AJAX handler provided by the form behavior. Below is a contents of the typical update.htm form.

<?= Form::open(['class'=>'layout']) ?>

    <div class="layout-row">
        <?= $this->formRender() ?>
    </div>

    <div class="form-buttons">
        <div class="loading-indicator-container">
            <button
                type="button"
                data-request="onSave"
                data-request-data="{ close: true }"
                data-hotkey="ctrl+enter, cmd+enter"
                data-load-indicator="Saving Category..."
                class="btn btn-default">
                Save and Close
            </button>
            <button
                type="button"
                class="oc-icon-trash-o btn-icon danger pull-right"
                data-request="onDelete"
                data-load-indicator="Deleting Category..."
                data-request-confirm="Do you really want to delete this category?">
            </button>
            <span class="btn-text">
                or <a href="<?= Backend::url('acme/blog/categories') ?>">Cancel</a>
            </span>
        </div>
    </div>

<?= Form::close() ?>

# Preview View

The preview.htm view represents the Preview page that allows users to preview existing records in the read-only mode. A typical Preview page contains breadcrumbs and the form itself. Below is a contents of the typical preview.htm form.

<div class="form-preview">
    <?= $this->formRenderPreview() ?>
</div>

# Extending Form Behavior

Sometimes you may wish to modify the default form behavior and there are several ways you can do this.

# Extending the Form Configuration

You may extend the form configuration dynamically using the formGetConfig method.

public function formGetConfig()
{
    $config = $this->asExtension('FormController')->formGetConfig();

    // Set the active tab dynamically
    $config->form['tabs']['activeTab'] = 'Content';

    return $config;
}

# Overriding Controller Action

You may use your own logic for the create, update or preview action method in the controller, then optionally call the Form behavior parent method.

public function update($recordId, $context = null)
{
    //
    // Do any custom code here
    //

    // Call the FormController behavior update() method
    return $this->asExtension('FormController')->update($recordId, $context);
}

# Overriding Form Save Data

You may use the formBeforeSave override (or equivalent) to change the save values of the form before it is saved or updated. To override the save value of a field use the formSetSaveValue(key, value) method.

public function formBeforeSave($model)
{
    // When locale dropdown is set to "custom", override with the _custom_locale text field
    if (post('MyModel[locale]') === 'custom') {
        $this->formSetSaveValue('locale', post('MyModel[_custom_locale]'));
    }
}

# Overriding Controller Redirect

You can specify the URL to redirect to after the model is saved by overriding the formGetRedirectUrl method. This method returns the location to redirect to with relative URLs being treated as backend URLs.

public function formGetRedirectUrl($context = null, $model = null)
{
    return 'https://octobercms.com';
}

# Extending Form Model Query

The lookup query for the form database model can be extended by overriding the formExtendQuery method inside the controller class. This example will ensure that soft deleted records can still be found and updated, by applying the withTrashed scope to the query:

public function formExtendQuery($query)
{
    $query->withTrashed();
}

# Extending Form Fields

You can extend the fields of another controller from outside by calling the extendFormFields static method on the controller class. This method can take three arguments, $form will represent the Form widget object, $model represents the model used by the form and $context is a string containing the form context. Take this controller for example:

class Categories extends \Backend\Classes\Controller
{
    public $implement = [
        \Backend\Behaviors\FormController::class
    ];

    public $formConfig = 'config_form.yaml';
}

Using the extendFormFields method you can add extra fields to any form rendered by this controller. Since this has the potential to affect all forms used by this controller, it is a good idea to check the $model is of the correct type. Here is an example:

Categories::extendFormFields(function($form, $model, $context) {
    if (!$model instanceof MyModel) {
        return;
    }

    $form->addFields([
        'my_field' => [
            'label' => 'My Field',
            'comment' => 'This is a custom field I have added.',
        ],
    ]);
});

You can also extend the form fields internally by overriding the formExtendFields method inside the controller class. This will only affect the form used by the FormController behavior.

class Categories extends \Backend\Classes\Controller
{
    // ...

    public function formExtendFields($form)
    {
        $form->addFields([...]);
    }
}

The following methods are available on the $form object.

Each method takes an array of fields similar to the form field configuration.

# Filtering Form Fields

As described in the field dependencies section, you may also implement form field filtering by extension by hooking in to the form.filterFields event.

User::extend(function ($model) {
    $model->bindEvent('model.form.filterFields', function ($formWidget, $fields, $context) use ($model) {
        if ($model->source_type === 'http') {
            $fields->source_url->hidden = false;
            $fields->git_branch->hidden = true;
        }
        elseif ($model->source_type === 'git') {
            $fields->source_url->hidden = false;
            $fields->git_branch->hidden = false;
        }
        else {
            $fields->source_url->hidden = true;
            $fields->git_branch->hidden = true;
        }
    });
});

# Validating Form Fields

To validate the fields of your form you can make use of the Validation trait in your model.