Module Development

Movie Project: Validate a Form for Drupal 7

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We're keeping this page up as a courtesy to folks who may need to refer to old instructions. We don't plan to update this page.

Make SQL queries in Drupal, make HTTP requests to external websites, and use this data to validate a form.


Query an external API to see if a movie already exists, and use this check to validate a form.


You will need the following knowledge and skills. If you need a review, check out the Additional resources section at the bottom of this page.

  1. Understand how to check for the existence of a property on a node.
  2. Create a validation hook for a form.
  3. Use an external API to access data to use for validation.


Create a function to check for the existence of a matching node within Drupal using the Drupal database abstraction layer. Return a boolean for whether it exists or not. If it does, notify the user that the node already exists.

Create a function which makes an API request to search for a movie in The Movie DB API with a matching title. If it does not exist, notify the user the movie does not exist in the external database. If it does exist, return the data object.


  • All database transactions happen via an abstraction layer.
  • Making requests to external URLs is simple in Drupal 7.

Further your understanding

Additional resources

Creative Commons License

Drupal Training Resources by Damian Robinson are licensed under a Creative Commons Attribution-ShareAlike 4.0 International License. Based on a work at

Hands-On Exercises: Movie Project