Stable Field Value Extraction module released

Okay, after weeks of nobody complaining about any aspect of my field_extract module I have finally got around to issuing the code as the full stable version. Hurray.

Now because I'm lazy I use Eclipse for development purposes - I know, I know, how can I be a proper developer if I don't use Linux and Vim? Well, I don't. I was using command line before you were born (unless you were born before 1983). Been there, done that.

However Eclipse and Drupal Git are strange bedfellows, and it can take a bit of work learning how they can be made to work together.

Getting Drupal repos cloned locally isn't too much of an issue once you've got your SSH keys sorted out, and for cloning you can happily use http.

Pushing upstream is another matter entirely (and you will to need to use just Push... instead of Push upstream... until you get it sorted out and configured). If you try using http you may well hit a brick wall, just as I did. the trick is to use git+ssh for your protocol, and it'll work nicely. One thing, which is obvious unless you forget it, is to include Add all tags spec if you are uploading tags as well as branches. Ahem.

Hopefully it won't be so long before my next posting - I have a fun new website specifically for developers coming up. I think you're going to like it, it provides a service that all developers need from time to time, and there is only one website I've found that fulfils the need, and not as well as my version. It's written in D7 of course, leveraging it as a development framework rather than a CMS.

And with that enigma, I'll leave you.

field_extract module in beta

EDIT: Now out of beta. Fully implemented.

EDIT: You can now get the module from http://drupal.org/project/field_extract and it works properly with Drush.

My incredibly useful field_extract module is now available on drupal.org. I am slightly embarrassed because something went wrong in the project creation process so the actual URL is:

http://drupal.org/project/1158878

And when you download it the module comes inside another folder "1158878". In fact this will work just as it comes, you'll just get the folder 1158878 in your modules folder with field_extract inside that.

If you're competent you can extract the inner "field_extract" module and get rid of the outer 1158878 folder but, as I say, it should work out of the box anyway. (I may get around to re-uploading it properly at some point but I can't wait any longer to get it out to you.)

So what does it do? For a start, this is only a developer's module. It does nothing by itself and should only be downloaded if requested by another module. But what it does do is provide a couple of functions that make it much easier to extract field data from entities.

The project page provides clear instructions on how to use it.

Enjoy.

Coming to a website near you

Now I don't want you to get too excited but I have recently completed two little Drupal 7 modules designed to make my life easier - so may well help other developers:

field_extract
This takes the little function I built to extract values from fields to the extreme by attaching "extractors" to the cached field type data, and then using the appropriate extractor to extract the data from a field. So there's one extractor that gets nodes, another that gets terms, another for fields, for body, for text, for integers and so on. It follows proper Drupal guidelines and is completely extensible.

archive_stream
Makes it easy to build a downloadable Zip archive using stream_wrappers. You give it a temporary filename and an array of file info arrays (or file entities) and it gives you a file path you can use for downloading. The module also handles the downloading part when a user accesses the link.

Simples.

It may take a few days to get them on to drupal.org but I'll let you know.

Getting field data out of entities

EDIT: download the module that encapsulates this behaviour and does a lot more besides: read this blog.

The new field structure in Drupal 7 is very clever but also quite irritating when you want to get data out of a field in an entity, so I have written this handy routine which extracts field data:


/**
 * Returns field values as actual entities where possible,
 * also allows selection of individual items to be returned
 */
function field_fetch_field_values($entity_type, $entity, $field_name, $get_delta = NULL, $get_key = NULL) {
  $values = array();
  if (isset($entity->$field_name) && !empty($entity->$field_name)) {
    foreach (field_get_items($entity_type, $entity, $field_name) as $delta => $item) {
      $value = $item;
      $keys = array_keys($item);
      if (count($keys)==1) {
        $key = $keys[0];
        switch ($key) {
          case 'nid':
            $value = array_shift(entity_load('node', array($item[$key])));
            break;
          case 'uid':
            $value = array_shift(entity_load('user', array($item[$key])));
            break;
          case 'tid':
            $value = array_shift(entity_load('taxonomy_term', array($item[$key])));
            break;
          case 'vid':
            $value = array_shift(entity_load('taxonomy_vocabulary', array($item[$key])));
            break;
          case 'value':
            $value = $item['value'];
            break;
        }
      }
      else {
        if ($get_key && isset($item[$get_key])) {
          $value = $item[$get_key];
        }
        elseif (array_key_exists('value', $item)) {
          $value = isset($item['safe_value']) ? $item['safe_value'] : $item['value'];
        }
      }
      $values[$delta] = $value;
    }
  }
  if (is_numeric($get_delta)) {
    return isset($values[$get_delta]) ? $values[$get_delta] : NULL;
  }
  return $values;
}


Use it like this:

$terms = field_fetch_field_values('node', $node, 'field_myterms');

Extracts all the tids from the field and returns the actual terms, not the tids.

$term = field_fetch_field_values('node', $node, 'field_myterms', 0);

Returns just the first term.

$summary = field_fetch_field_values('node', $node, 'body', 0, 'safe_summary');


Returns only the summary from the body field, but does not create a summary if there isn't one.


$info = field_fetch_field_values('node', $node, 'field_myfiles', 0);


If field_myfiles contains uploaded file data you get the full file info array back, in this example just the first one.


There are probably cleverer ways of doing this (and you could do multiple entity_loads to make it more efficient) but I find this works well enough for normal day-to-day use.

Proper way to get field values

EDIT: download the module that encapsulates this behaviour and does a lot more besides: read this blog.

If you haven't noticed the stored structure of fields in an entity, like a node, is not simple:

$entity ->fieldname[language][delta] = [item]

The Field API does contain useful functions for manipulating these values, so if you have a $node and a field_myfield, you can get the current items like this:

$items = field_get_items('node', $node, 'field_myfield', $node->language);

Which returns an array of the items in the field, indexed by their delta value.

The actual content of each item will be dependent on what it is, a simple textfield will have array('value' => [text]) while a term reference will have array('tid' => [tid]), a "longtext with summary" (such as the standard "body" field) has several values: for the main body ('value'), for the summary ('summary'), for the filter format ('format'), and already processed "safe" values of both the body (safe_value) and the summary (safe_summary).

You can find this, and other useful functions, at Field API.

EDIT: I now have a super-duper function that extracts values for you here.