Category: code

Gravity Forms is a great plugin many WordPress websites use. I’ve used it many client projects in the past and I’ve always missed a feature!

If you are a OS X user you are surely familiar with the “quick view” action – pressing space after selecting an item in Finder. I find this almost instinctive for me and miss it in many situations.

This feature is something which I miss in the list of GF entries. So I set out to build a plugin that does exactly that. This article will also include a step-by-step guide on how I built the plugin.

You can browse the code here or download the plugin here. If you also want to see how it’s built, read on.

Getting started

You should be comfortable coding WordPress plugins and I recommend using and IDE ( like PhpStorm ). This will make navigating a large plugin like Gravity Forms much simpler.

Finding a hook ?

First thing I did was to search for a hook to add the preview button to the list of entries. Easiest way, in my opinion, inspect the table and find something specific:

See that id there? “gf_entry_list” – next step is I went in the plugin folder and searched all the files:

Which is where I found the hook we are going to use: gform_entries_first_column_actions. This allows us to add an extra custom button next to the “edit”, “delete”, etc buttons.

Maybe going through the documentation is faster for some people but I find this method to be the most efficient for me.

Adding the button

The next step is going to be to add a button as the preview trigger. Because we are not in a OS interface I think it makes sense to have a click trigger.

Using the hook found above we add the button to the list of actions:

This will add the button ad the end of the list of actions:

<<
xt step is to add the id of the entry to the button and move on to the JS part. In this case, the $lead array contains the entry data ( as reflected by the PHPDoc comments ).

The actual functionality

Next we’ll need to add some JS into that page which will handle the loading of the preview. In these cases I usually start writing the code in a separate JS file, but if it turns out to be small I just use the proper hooks to load it only in that page. I’m not a fan of making an extra request although it is easier to maintain.

Adding scripts

Using the hook “admin_enqueue_scripts” the following function came to life:

Make sure you use the proper hook to avoid loading these scripts on other pages.

The JavaScript

As WP-admin already has it loaded, I used jQuery. Make sure to use the “promise” structure for the Ajax call as the old one is deprecated. Here’s the basic structure which we’ll use to go and define the Ajax handler in PHP.

Next up: the PHP which will handle the Ajax call and retrieve the GF entry data.

The PHP part of the Ajax call

For Ajax calls, WordPress has a very nice system in place which allows you to hook using the prefix “wp_ajax_” – if you you’re not familiar with it read more here.

Getting the entry data is not a big deal as GF has a proper API and we can use this function:

GFAPI::get_entry( $entry_id );

The only problem here is that the data has no human-readable labels, so it makes no sense.

In order to get over this, we’ll also need the form fields. In the end I decided to load the markup for the pop-up directly with the form table structure ( to avoid loading the form structure each time ).

You can find the form structure easily using:

GFAPI::get_form( $form_id );

In the array retrieved there there will be one entry for the “fields”. Just looping through them and through the entry data is enough. Luckily, GF takes care of ordering things properly for the API.

The markup

A good hook to load the markup of the quick-view panel is “gform_post_entry_list“. This is called at the end of the list and we can pre-load the table there and hide it with CSS.

I’ve loaded a simple markup there to display the info. Using the function mentioned above to retrieve the form structure we end up with something like this:

Linking it all together

Now that all components are in place we just need to send the entry data using the Ajax function and populate the html with it.

First we send the data using wp_send_json to make sure it goes out ok. Next, we loop through the list of labels and populate them with the data in the JSON.Now we can take care of the styles and using a CSS class we can toggle the visibility of the table. The final touch is to also allow users to close that table.

If you want to see the plugin in action you can browse the code here or download it here.

For those of you who didn’t know, TinyMCE has a straight-forward way to include a form in a modal window which you can use to generate shortcodes.

This is great news because it will make WordPress editors much less prone to error not having to write shortcodes by hand.

How do you do it?

So the approach in the WordPress way to do this is:

1. Add the button to the WordPress TinyMCE toolbar using the “mce_buttons” ( or others ) filter.
2. Ask TinyMCE to load a new JavaScript plugin for the editor which will handle the button.
3. In the TinyMCE JavaScript plugin add the button and handle its events.
4. Optionally if you have a custom shortcode, define it with its arguments.

In my example I have created a small plugin, which can be found on Github.

The plugin will add a button on the first row of the editor which when clicked will open a modal. The modal is handled by the WindowManager class included in TinyMCE. Another great part of using this approach is that you already have what is needed to generate a form.

After that, getting the parameters from the form and generating a shortcode to be inserted in the content is pretty easy.

You can get the whole plugin here.

I think the code is self-explanatory for the most part.

Things to watch out for

The code can be easily included in another plugin and extended to generate multiple buttons.

One issue I found not very intuitive at first is that if you add another button you will need to define another plugin for it to be taken into consideration, even if it’s in the same file.

So in the function where you add the js plugins you’ll end up with:

function add_embed_button_js( $plugin_array ) {

   $plugin_array['msb_button'] = plugin_dir_url( MSB_PLUGIN_FILE ) . 'assets/js/embed_button.js';
   $plugin_array['msb_button_2'] = plugin_dir_url( MSB_PLUGIN_FILE ) . 'assets/js/embed_button.js';

   return $plugin_array;

}

I trust that TinyMCE won’t attempt to load the same file 2 times. Also I am aware it might not be the right approach but it works!

Also, as mentioned in the plugin README – by default the plugin will add a button with no icon so you might miss it.

UPDATE: For the WooCommerce-friendly version of this, see this article.

I think the title is self-explanatory but let’s detail the situation a bit:

Let’s presume you have a custom post type for Cars and for each car you have the VIN number in a custom field. You want to allow users to search from the admin directly by that field. Also, you need them to use the default search input:

The code

First we have to find the right hook to extend the search with. In our case I found the best results with the posts_search filter.

Next, the logic! Keep in mind this filter is being called in the get_posts function of the WP_Query class, so everywhere. That results in adding a check to see if we are on the right page.

Also, keep in mind that we are altering the “where” part of the actual SQL query.

Further usage

Like I mentioned before – this snippet checks if the search is performed in the admin, but that also means you can use it in the frontend. So if you’d like to extend the default WordPress search to enable custom field searches you can change the logic at the top. This can be easily switched to enable WooCommerce products search by SKU or similar.

Recently I had to develop a WordPress plugin that is used to manage files stored on Amazon AWS S3. Due to the nature of the files which contain sensible information they are stored as private and using the AES256 ServerSideEncryption.

In order to serve the files to authorized users an AJAX call is used to generate a temporary link from the AWS PHP SDK. My problem is that for these links the “content-disposition” header is set to “attachment” which forces a download. As the client wanted to offer the option to also view directly in the browser these ( PDF ) files, I was faced with a problem.

Previewing the files without forcing a client download

The Amazon AWS documentation specifies an optional content-disposition parameter. So, for example, in a “getObjectUrl” call you would use:

$args = array(
    'ResponseContentDisposition' => 'attachment; filename=testing.pdf'
);
$request = $s3Client->getObjectUrl( $bucket, 'example/test.pdf', '+2 minutes', $args );

Those arguments get passed to the “getObject” function as explained here. The problem is that for some reason this parameter is ignored – probably because of the encryption.

I found a quick solution to this problem by downloading the file and serving directly from PHP on my server instead of trying to change the content-disposition on Amazon’s requests.

So in the WordPress plugin I added a simple function which takes a file and serves it with content-disposition inline:

add_action( 'wp_ajax_m_view_link', array( $this, 'view_pdf' ) );

function view_pdf() {

   if ( isset($_GET['url']) && is_user_logged_in() ) {

      header('Content-disposition: inline; filename='.basename($_GET['url']));
      header("Content-type:application/pdf");

      echo file_get_contents($_GET['url']);

   }

   die();

}

So now when calling /wp-admin/admin-ajax.php?action=m_view_link&url=url_of_amazon_file the users can preview the files directly in their browsers.

Notes:

To prevent potential security threats you should add some checks to the “view_pdf” function above.

Obviously you can use this for other purposes than Amazon S3 files it’s a quick way to change the content-disposition of certain external files.