Laravel Validation: sometimes vs nullable

sometimes: Only apply the rest of the validation rules if the field shows up in the request.
nullable: If the field shows up in the request and is null (undefined, empty, has no value at all, etc), do not apply the rest of the validation rules.

sometimes

sometimes adds the defined validation conditions to a given field if the field is present in the request.

It’s therefore useful in situations where you wish to run validation checks against a field only if that field is present in the request.

Take for instance the examples presented in this answer by haakym on Stackoverflow (also presented below).

I use this rule when I have some javascript on a page that will disable a field, as when a field is disabled it won’t show up in the request. If I simply said required|email the validator is always going to apply the rules whereas using the sometimes rule will only apply the validation if the field shows up in the request! Hope that makes sense.

Examples:

input: []
rules: ['email' => 'sometimes|required|email']
result: pass, the request is empty so sometimes won't apply any of the rules

input: ['email' => '']
rules: ['email' => 'sometimes|required|email']
result: fail, the field is present so the required rule fails!

input: []
rules: ['email' => 'required|email']
result: fail, the request is empty and we require the email field!

nullable

By default, Laravel includes the TrimStrings and ConvertEmptyStringsToNull middleware in your application’s global middleware stack. These middleware are listed in the stack by the App/Http/Kernel class.

TrimStrings takes care of Stripping whitespace (or other characters) from the beginning and end of each field in the request.
ConvertEmptyStringsToNull as it’s name suggests checks each field and if a field is just an empty string, it assigns null to it. Say the field was name="", it’ll be transformed into name=null.

Because of this, you will often need to mark your “optional” request fields as nullable if you do not want the validator to consider the null values as invalid. For example:

    $this->validate($request, [
        'title' => 'required|unique:posts|max:255',
        'body' => 'required',
        'publish_at' => 'nullable|date',
    ]);

In this example, we are specifying that the publish_at field may be either null or a valid date representation. If the nullable modifier is not added to the rule definition, the validator would consider null an invalid date.

Laravel Validation: sometimes vs nullable

Tags

sometimes

nullable

Further reading