问题
What is the difference between sometimes|required|email and sometimes|email in Laravel validation?I've read this discussion from laracasts but still it is ambiguous for me
回答1:
From the docs:
In some situations, you may wish to run validation checks against a field only if that field is present in the input array. To quickly accomplish this, add the sometimes rule to your rule list
https://laravel.com/docs/5.2/validation#conditionally-adding-rules
If I could simplify it, I would say sometimes means, only apply the rest of the validation rules if the field shows up in the request. Imagine sometimes is like an if statement that checks if the field is present in the request/input before applying any of the rules.
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!
来源：https://stackoverflow.com/questions/35839414/laravel-sometimes-vs-sometimesrequired