Clarification needed for validation rules and scenarios in definitive guide

[azizkh]

Hi, I've just started reading a Yii2 guide about Model and get little confused about scenarios mentioned in Model::rules and Model::scenarios. I can't really understand why we need to scenarios in rules. From guide:

A)

function rules()
{
    return [
        // rule applied when corresponding field is "safe"
        ['username', 'string', 'length' => [4, 32]],
        ['first_name', 'string', 'max' => 128],
        ['password', 'required'],

        // rule applied when scenario is "signup" no matter if field is "safe" or not
        ['hashcode', 'check', 'on' => 'signup'],
    ];
}

function scenarios()
{
    return [
        // on signup allow mass assignment of username
        'signup' => ['username', 'password'],
        'update' => ['username', 'first_name'],
    ];
}

B)
"Sometimes, we want to mark an attribute as not safe for massive assignment (but we still want the attribute to be validated). We may do so by prefixing an exclamation character to the attribute name when declaring it in scenarios(). For example:

['username', 'password', '!secret']";

Confusion: Isn't A) and B) the same?
I mean is A) and following code is equivalent?

function rules()
{
    return [
        // rule applied when corresponding field is "safe"
        ['username', 'string', 'length' => [4, 32]],
        ['first_name', 'string', 'max' => 128],
        ['password', 'required'],

        // removed 'on'=>'signup'
         ['hashcode', 'check']
    ];
}

function scenarios()
{
    return [
        // on signup allow mass assignment of username,
        // but also validate hashcode
        'signup' => ['username', 'password', '!hashcode']";
        'update' => ['username', 'first_name'],
    ];
}

Thanks

[cebe]

You are right, scenario is in most cases not needed in rules(). Your examples are equivalent.

But you can specify rules() without defining scenarios() method which will result in the scenarios() method to determine the scenarios and active attributes based on the definitions in rules().
This is what sceanrios is mostly used for in rules()

// rule applied when corresponding field is "safe"

is not 100% correct.
rule is applied when field is active: https://github.com/yiisoft/yii2/blob/master/docs/guide/model.md#active-attributes

rule applied when scenario is "signup" no matter if field is "safe" or not

This will not be applied as the attribute is not active on signup as defined by your scenarios() method. Actually I just found that the current implementation is not correct according to docs and how it should be. Will fix this.

Example:

function rules()
{
    return [
        // rule applied when corresponding field is "active"
        ['username', 'string', 'length' => [4, 32]],
        ['first_name', 'string', 'max' => 128],
        ['password', 'required'],

        // rule applied when scenario is "signup" no matter if field is "safe" or not
        ['hashcode', 'check', 'on' => 'signup'],
    ];
}
// this will result in scenarios beeing auto detected as:
[
        'default' => ['username', 'password', 'first_name'],
        'signup' => ['username', 'password', 'first_name', 'hashcode'],
];
}

[o-rey]

Btw 'except' does not affect scenario fields.
Given this set of rules,

return [
    [['id'], 'required', 'except' => 'administration'],
    [['name', 'description'], 'filter', 'filter' => 'trim'],
    [['is_disabled'], 'boolean', 'on' => 'administration'],
];

these scenarios are generated:

Array
(
    [administration] => Array
        (
            [0] => is_disabled
            [1] => id
            [2] => name
            [3] => description
        )

    [default] => Array
        (
            [0] => id
            [1] => name
            [2] => description
        )

)

As you can see in this case the field "id" is still present in 'administration' scenario. I suppose this behavior should be either documented or fixed also.

And it does not produce any new scenario, so in this example:

return [
    [['id'], 'required', 'except' => 'suddenlyUnexpectedScenario'],
    [['name', 'description'], 'filter', 'filter' => 'trim'],
    [['is_disabled'], 'boolean', 'on' => 'administration'],
];

the scenario list remain the same: 'default' + 'administration', and no 'suddenlyUnexpectedScenario'.

[qiangxue]

@o-rey good find. I just fixed the issue.

[samdark]

@cebe is it closed by mistake?

[cebe]

Yep. merged qiangs commit and gihub closed it :-/

[qiangxue]

Closed as the doc seems to be complete now.