Drupal 7 hook menu validating argument from url
Instead of handling the entire form, #element_validate helps to trigger a specific field validation and displaying custom error message.Validate Only Individual form element with pre define validation handler: Drupal has a lot of pre define validators.As of now there are a list of functions available to execute basic validation over form.Validate function using _form_validate from drupal API We can add custom handler to validate the data entered into the field. It is simply the name of the form followed by '_validate'.Drupal has already defined a handler that validates if the data is a number, called element_validate_number.So we need to add the following to our form element: Just one line of code can handle validation. An individual form element handler with pre define core function, does not allow you to write custom error messages.If you're looking for hands-on training about how to develop Drupal modules, we offer professional Drupal training online and in-person.See the full Drupal 8 Module Development training curriculum for details.
Use a pre-defined validation handler to validate numbers/integers.This happens with Views that are filtered by a taxonomy term in the URL.The result is that you end up seeing taxonomy term IDs in the URL (e.g. In this tutorial, I'll walk you through how to create a field that is used to make generate URLs for Views pages that take taxonomy terms as contextual arguments.The plugin takes a term ID from the URL and passes it to Views.We'll override the plugin so that it takes a string from the URL (slug), and then looks up the associated term ID.