adding image upload functionality to your module

A while back I was asking about how to easily incoporporate image.module functionality into a module.

I got it working and thought I would share it here in case anyone else is trying to do this. This solution requires under 50 lines of code and will ignore the image functionality if image.module is not enabled on the site.

Step 1. hook_form

Add this code into your hook_form function.

  // image form code
  if(function_exists('_image_check_settings')){
    _image_check_settings();
    $param['options'] = array("enctype" => "multipart/form-data");
    if (is_array($node->images)) {
      foreach ($node->images as $label => $image) {
        $output .= form_hidden('images]['.$label, $image);
      }
    }
    if ($node->images['thumbnail']) {
      $output.= form_item(t('Thumbnail'), image_display($node, 'thumbnail'));
    }
    $output .= form_file(t('Image'), 'image', 50, t('Click "Browse..." to select an image to upload.'), TRUE);
  }

Step 2. hook_insert

First, you will need to change hook_insert($node) to hook_insert(&$node). This is because image_validate acts on the $node object and if you do not import the reference to the actual $node object via the '&' prefix, these changes will be lost. After this change has been made, add this code:

  // image insert code (remember that image.module acts on $node to create $node->images)
  if(function_exists('image_validate') && function_exists('_image_insert')){
    image_validate($node, 'image');
    foreach ($node->images as $label => $image) {
      _image_insert($node->nid, $label, file_create_path($image));
    }
  }

Step 3. hook_update

First change hook_update($node) to hook_update(&$node) for the same reasons listed above. Then add this code to the function:

  // image update code
  if(function_exists('image_validate') && function_exists('_image_insert')){
  image_validate($node, 'image');
  foreach ($node->images as $label => $image) {
    $old_path = db_result(db_query("SELECT filepath FROM {files} WHERE filename='%s' AND nid=%d", $label, $node->nid));
    // This is a new image.
    if ($old_path != $image) {
      file_delete(file_create_path($old_path));
      db_query("DELETE FROM {files} WHERE filename='%s' AND nid=%d", $label, $node->nid);
      _image_insert($node->nid, $label, file_create_path($image));
    }
  }

Step 4. hook_view / your custom view theme function

Now we want to put the following code into either hook_view or the custom theme function you are using to view a node created by your module. This method can also be used to add the image into the teaser.

  // image view code
  if(function_exists(image_display)){
    if($node->images){
      $request = ($_GET['size']) ? $_GET['size'] : 'preview';
      $output .= l(image_display($node, 'thumbnail'), 'node/'.$node->nid, array(), NULL, NULL, FALSE, TRUE);
    }
  }

Step 5. settings / admin

The above code uses the function_exists check and is written in such a way that if the Image module is not enabled on your site, all the image code will be ignored. As a result, you may want to allow system admins to know why the image functionality is not available for their site. Add something like this in your settings / admin screen:

  // Let the admin know that images are not enabled if the module is not found
  if(!function_exists(_image_check_settings)){
    drupal_set_message(t('The Image module is not enabled. This module needs it enabled in order to allow users to upload images. If you would like to take advantaeg of the image upload functions, please enable image module.'), 'message');
  }

Hope that saves people some time. Any suggestions are welcome.

Also, as Boris Mann and sepeck suggested to me, check out the code from walkah's image.module and mathias' img_assists for more.

Enjoy.