New Feature: Playlist Center! Pick a topic and let our playlists guide the way.

Start learning with our library of video tutorials taught by experts. Get started

Drupal 7 Custom Module Development
Illustration by

Handling successful form submissions and saving variables


From:

Drupal 7 Custom Module Development

with Jon Peck

Video: Handling successful form submissions and saving variables

Once validation is passed, the Drupal form API looks for submit callback. Return to the IDE, then create a new docblock for the submission callback. Process a validated Wind Farm admin setting submission. Similar to the way the validate function was named, a submit callback name starts with the form name followed by underscore submit. Same as a validate function, it takes two parameters; the form then the form state passed by reference; windfarms_admin_settings_form_submit, form then form_state, passed by reference.

Watch this entire course now—plus get access to every course in the library. Each course includes high-quality videos taught by expert instructors.

Become a member
please wait ...
Drupal 7 Custom Module Development
2h 57m Advanced Oct 16, 2012

Viewers: in countries Watching now:

Extend your Drupal 7 sites with custom modules, which allow you to create everything from admin interfaces to forms. Author Jon Peck describes how modules extend your base Drupal installation, then walks through how to write your own module with a practical example featuring geo-positioned alternative energy centers. The course also describes how to control access to site features, create new content types, build forms, understand data persistence, embrace coding standards, and much more.

Topics include:
  • Creating your first module
  • Interacting with hooks
  • Working with permissions and roles
  • Controlling access
  • Adding a menu item to an admin interface
  • Using the Form API (FAPI) to quickly create a form
  • Creating custom form validation
  • Manually creating a custom content type
  • Validating user input
  • Importing content using feeds
  • Creating a block
  • Understanding best practices and coding standards
Subjects:
Developer Web CMS Blogs Web Design Programming Languages Web Development
Software:
Drupal
Author:
Jon Peck

Handling successful form submissions and saving variables

Once validation is passed, the Drupal form API looks for submit callback. Return to the IDE, then create a new docblock for the submission callback. Process a validated Wind Farm admin setting submission. Similar to the way the validate function was named, a submit callback name starts with the form name followed by underscore submit. Same as a validate function, it takes two parameters; the form then the form state passed by reference; windfarms_admin_settings_form_submit, form then form_state, passed by reference.

The first thing I want to do is tell the form to rebuild so the submitted values will be displayed even on success, instead of showing the default values. To do that I will manually set a flag in the form state. As form state was passed by reference, changes within this function will affect other form processors. The flag name is rebuild and accept Boolean values true or false. I'll start with a comment to describe what I'm about to do; Rebuild the form, form_state key rebuild = TRUE, save the module then return to the browser.

Change the input to something valid, but different. This time the form elements contain the submitted input. Next load the page without a form submission and the default values are shown. To complete this interface I need to be able to save the settings. Drupal provides a mechanism for persistent variables that allows for practically any datatype to be stored in the database. There are three functions: variable_get which gets a value by name and optionally provides default value if the variable has never been set, variable_set which saves a value to the database by name, and variable_del which deletes a value from the database by name.

Variables are useful for settings but in general should not be used for content. Variable names are, by best practice, lowercase and separated by underscores and start with a module name. Go back to the IDE and navigate the form creation of windfarms_gmap, and in particularl the default_value. Instead of just defaulting to 1, I will change it to use variable_get and use 1 as the default value, variable_get windfarms_ gmap and set the default value.

The name is passed as a string and I will use the same name as the form element. Now if the windfarms_gmap has never been set it will default to 1. I will do the same for the latitude, variable_get, windfarms_default_center_lat, and for the longitude, variable_get windfarms_default_center_long.

And finally the zoom; variable_get, windfarms_default_gmap_zoom. Now that the form can get the default for the variables let's set the variables upon a successful form submission. Return to the form submit callback then, beneath the form state add a comment describing what is about to happen; Save Wind Farm setting variables.

Use variable set in the form state values. No additional manipulation of the input is needed as the form API handles the input sanitization and variable_get handles the database interactions. Variable_set, windfarms_gmap which is from form _state values, windfarms_gmap; variables_set, windfarms _default_center_lat which is from the form_state once again with the same name.

Do the same for the longitude and finally the zoom, windfarms_default_gmap_zoom, save then return to the browser. Change the form values to something valid and click Save. 35 and 40.

The page looks like it did before when it passed validation complete with a new input. Reload the page without a form submission to verify the persistence of the variables. As it stands, the admin interface is functional but lacks a usability touch. There is no feedback to the user when the settings are saved. Drupal core has a mechanism to store user messages within the session and display them. To set one of these messages use drupal_set_message.

Return to the IDE and the form submit callback. At the end, provide an appropriate message to the user stating that the variables have been saved. Drupal set message takes two parameters. The first which is required is the message itself wrapped in the t function. The second is an optional message type, the default is status. Developers can also set warning and error messages, start with a comment for context. Notify user, then set the message, Drupal_ set_message t Wind farm settings saved.

Finally, as development in this admin section is complete remove the TPM debugging call within the validator. Save the module and then return to the browser. Save new settings and this time the message is displayed to the user and no debugging information is shown. In the next, segment I will demonstrate best practices with variable persistence using module install and uninstall hooks.

Find answers to the most frequently asked questions about Drupal 7 Custom Module Development.


Expand all | Collapse all
please wait ...
Q: gmap3_tools is not working the way I expected it to. What version of gmap3_tools should I be using?
A: Use the free exercise file containing the version of gmap3_tools used for recording; the published version of the module on drupal.org has changed since recording and is not backwards compatible.
Q: I attempted to run the Drupal site root from the project files, but the site isn't loading. Why not?
A: The Drupal configuration file in sites/default/settings.php contains database configuration specific to the environment used to record the movie. This may be different than your environment. Edit the file and search for "windfarms" - you may need to change the database host, username, password, db name and port to match your specific environment.
 
Share a link to this course

What are exercise files?

Exercise files are the same files the author uses in the course. Save time by downloading the author's files instead of setting up your own files, and learn by following along with the instructor.

Can I take this course without the exercise files?

Yes! If you decide you would like the exercise files later, you can upgrade to a premium account any time.

Become a member Download sample files See plans and pricing

Please wait... please wait ...
Upgrade to get access to exercise files.

Exercise files video

How to use exercise files.

Learn by watching, listening, and doing, Exercise files are the same files the author uses in the course, so you can download them and follow along Premium memberships include access to all exercise files in the library.
Upgrade now


Exercise files

Exercise files video

How to use exercise files.

For additional information on downloading and using exercise files, watch our instructional video or read the instructions in the FAQ.

This course includes free exercise files, so you can practice while you watch the course. To access all the exercise files in our library, become a Premium Member.

join now Upgrade now

Are you sure you want to mark all the videos in this course as unwatched?

This will not affect your course history, your reports, or your certificates of completion for this course.


Mark all as unwatched Cancel

Congratulations

You have completed Drupal 7 Custom Module Development.

Return to your organization's learning portal to continue training, or close this page.


OK
Become a member to add this course to a playlist

Join today and get unlimited access to the entire library of video courses—and create as many playlists as you like.

Get started

Already a member?

Become a member to like this course.

Join today and get unlimited access to the entire library of video courses.

Get started

Already a member?

Exercise files

Learn by watching, listening, and doing! Exercise files are the same files the author uses in the course, so you can download them and follow along. Exercise files are available with all Premium memberships. Learn more

Get started

Already a Premium member?

Exercise files video

How to use exercise files.

Ask a question

Thanks for contacting us.
You’ll hear from our Customer Service team within 24 hours.

Please enter the text shown below:

The classic layout automatically defaults to the latest Flash Player.

To choose a different player, hold the cursor over your name at the top right of any lynda.com page and choose Site preferencesfrom the dropdown menu.

Continue to classic layout Stay on new layout
Exercise files

Access exercise files from a button right under the course name.

Mark videos as unwatched

Remove icons showing you already watched videos if you want to start over.

Control your viewing experience

Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.

Interactive transcripts

Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.

Are you sure you want to delete this note?

No

Thanks for signing up.

We’ll send you a confirmation email shortly.


Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

Keep up with news, tips, and latest courses with emails from lynda.com.

Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

   
submit Lightbox submit clicked
Terms and conditions of use

We've updated our terms and conditions (now called terms of service).Go
Review and accept our updated terms of service.