Enter one thing but save the other

Question

I try to construct a field and I wonder how should I implement this process via Field API:

1. User enter some data to the field. Let's say, the data entered is a node title.
2. User hits the "Save" button, but what is actually saved in the database is the node ID of the node whose title has been entered by the user.

Something like this happens with the Entity Reference module: I enter the title of the entity (as I 'm getting assistance through autocomplete), but the module saves target_id, not the title I have actually entered.

How can I gain such behavior?

Answer 1

Create a module for example module name is rose. In that module implement hook_node_validate

function rose_node_validate($node, $form, &$form_state) {
       //Check to see if this is the node form data you want to change
    if ($form['#form_id'] == 'contentType_node_form') {
        //based on the value provided in 
        $form_state['input']['field_name']['und'][0]['value'];
        $new_info_data = 'some logic'; //get the data you would like to save .
        variable_set('new_info', $new_info_data); //Save the data in a variable.
    }
}

Then implement a hook_node_presave. As per our example

function rose_node_presave($node) {
    //check if the node type is the one you want to change the value
    if ($node->type == 'content_type') {
        $new_info = variable_get('new_info'); //get the value which was set in validation variable_set()
        $node->field_name['und'][0]['value'] = $new_info;
    }
}

I have implemented this on Drupal 7. A user enters instagram user name and I get the instagram id from instagram api and save it. Let me know if more explanation is required.

In this implementation users enters only address I get the Lat and Lng based on the address provided and save it in the database.

Answer 2

ok.let's suppose your entity ref field name is field_entity_ref
you should to create anther field (text) field , name it field_book_title
in you custom module hook_form_alter

  function custommodule_form_alter($form, &$form_state,$form_id) {
     if ($form_id == 'yourcontetntpe_form_node') {
        $form['#submit'][] ='mycustom_function';
        // we must hide shadow field in view 
        // first check #access=false if not work comment it and use hide
         $form['field_book_title']['#access'] = false;
        // or you can hide it
        // hide($form['field_book_title']);
       }
   }

and in mycustom_function function get nid of refrenced node , load node and save it's title in field_book_title.

function mycustom_function(form,&$form_state) {
  $node = node_load($form_state['values']['field_entity_ref']['und'][0]['target_id']);
  $form_state['values']['field_book_title']['und'][0]['value'] = $node->title; 
 }

And finally in view of node (in your tpl or in views) use field_book_title instead of field_entity_ref

I hope this be useful for you.