Best way to render a form on a node?

Question

I am trying to add a textfield to the bottom of a node (for a specific cck type), that once (an authenticated user) submits, stores the value as a term in a taxonomy vocabulary.

What is the best way to do so?

I have tried adding the form to my subtheme's node.tpl.php file for a custom cck type.

I am having trouble with form validation. I'm able to submit the form properly, but get the red borders around the field that needs to be validated, instead of the message; Until I resubmit and the cached error message then shows. I get why it's happening - code executing prior to node.tpl.php load. See - How do I use form_set_error() the right way?.

If Form Builders are not supposed to be called from within a template file, how else can I add a form to a page? I'm sort of working off this form example tutorial

I started with this - Embed form inside a block - and since added this to my node.tpl - https://gist.github.com/1847060.

I'm still trying to wrap my head around using the forms api, so thanks for any advice.

Answer 1

From what I've read and tried it seems like if you want the messages to appear correctly the form needs to be built latest in the template_preprocess_page() function. Doing it in template_preprocess_node() or in the theme template files is too late with Drupal 7. To put this into the code you could declare a variable that holds the form for your node template in your theme's template.php file:

function mytheme_preprocess_page(&$variables) {
  // For node templates.
  $variables['node']->my_form = drupal_get_form('form_name');
  // For page templates.
  // $variables['my_form'] = drupal_get_form('form_name');
}

Then you can render the form in your template file:

<?php print render($my_form); ?>

This way the messages appear when they should not one page call too late.

Answer 2

You want to avoid putting this into your node template. Generally you want to keep "business logic" (any php functions other than print) out of template files. You might be better served by creating this as a block and placing it below or above the node because it is more reuseable. If you don't want to use a block you can use hook_node_view() and add an additional element to $node->content as in the linked example.

Answer 3

/**
 * Implements hook_node_view()
 */
function MYMODULE_node_view($node, $view_mode, $langcode) {
  // prepare the form
  $form = drupal_get_form('a_very_simple_form');
  // append a new field to the content
  $node->content['a_new_field'] = array(
    '#markup' => drupal_render($form), // and render the form there
    '#weight' => 10,
  );
}

function a_very_simple_form($form, &$form_state) {
  $form['submit_button'] = array(
    '#type' => 'submit',
    '#value' => t('Submit'),
  );
  return $form;
}

See hook_node_view() for more information.

Answer 4

The Webform module has an "Available as block" option, which can be placed on whichever pages using the Block UI, Context or Panels (if you're into that sort of thing, but I don't recommend it).

I found this over at How to embed a webform in a node in drupal 7. This was also mentioned over at Embedding a webform inside a node content and Add webform to content type.