Title: Help Me Develop a Plugin
Last modified: August 18, 2016

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# Help Me Develop a Plugin

 *  [coolkarthik88](https://wordpress.org/support/users/coolkarthik88/)
 * (@coolkarthik88)
 * [19 years, 9 months ago](https://wordpress.org/support/topic/help-me-develop-a-plugin/)
 * Hey guys i just wanted to develop a simple plugin for my personal use. I want
   to have an additional field in the Create New Post/Page page that inputs an url
   for that particular post.. Basically every differant post should have a differant
   url but they needn’t be unique..
 * And in the single.php or page.php I want to display this url.. As simple as that..
   But I am not used to coding plugins for wordpress so I have just asked you guys..
 * Please help…

Viewing 15 replies - 1 through 15 (of 18 total)

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 *  [schulte](https://wordpress.org/support/users/schulte/)
 * (@schulte)
 * [19 years, 9 months ago](https://wordpress.org/support/topic/help-me-develop-a-plugin/#post-429252)
 * Redirectify perhaps?
 * [http://www.redalt.com/downloads/](http://www.redalt.com/downloads/)
 *  Thread Starter [coolkarthik88](https://wordpress.org/support/users/coolkarthik88/)
 * (@coolkarthik88)
 * [19 years, 9 months ago](https://wordpress.org/support/topic/help-me-develop-a-plugin/#post-429292)
 * well it is something similar i guess. Well thanks for the plugin…
 *  Thread Starter [coolkarthik88](https://wordpress.org/support/users/coolkarthik88/)
 * (@coolkarthik88)
 * [19 years, 9 months ago](https://wordpress.org/support/topic/help-me-develop-a-plugin/#post-429308)
 * no this is not what i want..
 * i want a plugin that inputs a url from the create post page and displays that
   url on the Post itself(single)..
 * bascially i want the url to be in wp-posts table as a column.
 *  [yami](https://wordpress.org/support/users/yami/)
 * (@yami)
 * [19 years, 9 months ago](https://wordpress.org/support/topic/help-me-develop-a-plugin/#post-429309)
 * Why not just use a custom field? Then you can display it with [Scott Reilly’s get custom field](http://www.coffee2code.com/wp-plugins/)
   plugin.
 *  [yoshi](https://wordpress.org/support/users/yoshi/)
 * (@yoshi)
 * [19 years, 9 months ago](https://wordpress.org/support/topic/help-me-develop-a-plugin/#post-429310)
 * I don’t know why just using custom field isn’t good enough.
 * However, if for any reason you REALLY need it in the wp_posts table, try this.
 * posturl.php ==================================
    ` <?php /* Plugin Name: posturl
   Plugin URI:  Description:  Author: Yoshi Version: 0.5b */
 * add_action('wp_insert_post', 'posturl_insert_post');
    function posturl_insert_post(
   $pID) { global $wpdb;
 *  extract($_POST);
 *  $wpdb->query(
    "UPDATE $wpdb->posts SET post_url = '$post_url'  WHERE ID = $
   pID");
 * }
 *  add_action('dbx_post_sidebar', 'posturl_addfield');
 * function posturl_addfield() { 
    global $post; ?> <fieldset id="posturl" class
   ="dbx-box"> <h3 class="dbx-handle"><?php _e('Post URL'); ?>:</h3> <div class="
   dbx-content"><input name="post_url" type="text" size="13" id="post_url" value
   ="<?php echo $post->post_url ?>" /></div> </fieldset>
 * <?php
    }
 *  add_action('activate_posturl.php', 'posturl_addcolumn');
 * function posturl_addcolumn () {
    global $wpdb; $wpdb->query("ALTER TABLE $wpdb-
   >posts ADD COLUMN post_url varchar(128)"); } ?>
 * =============================================
    And post_url can be called like
   <?php echo $post->url ?> in your template.
 * Should have url validation and display function but don’t have time right now…
 *  Thread Starter [coolkarthik88](https://wordpress.org/support/users/coolkarthik88/)
 * (@coolkarthik88)
 * [19 years, 9 months ago](https://wordpress.org/support/topic/help-me-develop-a-plugin/#post-429312)
 * oh thanks for the help I’ll see if this helps me..
 *  Thread Starter [coolkarthik88](https://wordpress.org/support/users/coolkarthik88/)
 * (@coolkarthik88)
 * [19 years, 9 months ago](https://wordpress.org/support/topic/help-me-develop-a-plugin/#post-429313)
 * Well I modified which yoshi gave me but it dosen’t work perfectly..
 * I have two problems :
    1) The URL is not added to the database 2) How on earth
   am i supposed to show the url on post (please write the display function..)
 * Well here is my code..
 * `
    <?php /* Plugin Name: Digg This Plugin URI: http://xyz.com Description: Adds
   the Digg URL to your site.. Author: Karthik Version: 1.0 */
 * add_action('wp_digg_this', 'diggurl_insert_post');
    function diggurl_insert_post(
   $pID) { global $wpdb;
 * extract($_POST);
 * $wpdb->query(
    "UPDATE $wpdb->posts SET digg_url = '$digg_url' WHERE ID = $pID");
 * }
 * add_action('dbx_post_sidebar', 'diggurl_addfield');
 * function diggurl_addfield() {
    global $post; ?> <fieldset id="posturl" class="
   dbx-box"> <h3 class="dbx-handle"><?php _e('Enter the Digg URL'); ?>:</h3> <div
   class="dbx-content"><input name="digg_url" type="text" size="21" id="digg_url"
   value="<?php echo $post->digg_url ?>" /></div> </fieldset>
 * <?php
    }
 * add_action('activate_diggthis.php', 'diggurl_addcolumn');
 * function diggurl_addcolumn () {
    global $wpdb; $wpdb->query("ALTER TABLE $wpdb-
   >posts ADD COLUMN digg_url varchar(128)"); }
 * add_action('deactivate_diggthis.php', 'diggurl_removecolumn');
 * function diggurl_removecolumn () {
    global $wpdb; $wpdb->query("ALTER TABLE $
   wpdb->posts DROP `digg_url`“); }
 * function show_digg_this () {
 * }
    ?>
 * Please help me out..
 *  [yoshi](https://wordpress.org/support/users/yoshi/)
 * (@yoshi)
 * [19 years, 9 months ago](https://wordpress.org/support/topic/help-me-develop-a-plugin/#post-429316)
 * 1) `add_action('wp_digg_this', 'diggurl_insert_post');`
    this should be `add_action('
   wp_insert_post', 'diggurl_insert_post');`
 * I have not read through your code carefully so there might be somewhere else 
   to fix. If it still doesn’t work please try my original code and let me know 
   if it works.
 * 2) The simplest one would be something like:
    ` function show_digg_this () { 
   $post = &get_post(); $diggurl = $post->digg_url(); if ( strlen($diggurl) > 0 )
   echo '<a href="' . $diggurl . '">' . $diggurl . '</a>'; }
 * And you can call <?php show_digg_this (); ?> in your template.
 * Again, don’t forget to add some validation at submission and display(especially
   if you allow users to post).
 * Regards,
 * // can anyone let me know how to indent within the code?
 *  Thread Starter [coolkarthik88](https://wordpress.org/support/users/coolkarthik88/)
 * (@coolkarthik88)
 * [19 years, 9 months ago](https://wordpress.org/support/topic/help-me-develop-a-plugin/#post-429317)
 * Well I have got most of it working..
 * But there are some problems. The Digg url still dosen’t show up eventhough it
   is there in the database..
 * And how do i get the permalink of the post in the code (see below)
 * add_action('wp_insert_post', 'diggurl_insert_post');
    function diggurl_insert_post(
   $pID) { global $wpdb;
 * extract($_POST);
 * $wpdb->query(
    "UPDATE $wpdb->posts SET digg_url = '$digg_url' WHERE ID = $pID");
 * }
 * add_action('dbx_post_sidebar', 'diggurl_addfield');
 * function diggurl_addfield() {
    global $post; ?> <fieldset id="posturl" class="
   dbx-box"> <h3 class="dbx-handle"><?php _e('Enter the Digg URL'); ?>:</h3> <div
   class="dbx-content"><input name="digg_url" type="text" size="21" id="digg_url"
   value="<?php echo $post->digg_url ?>" /></div> </fieldset>
 * <?php
    }
 * add_action('activate_diggthis.php', 'diggurl_addcolumn');
 * function diggurl_addcolumn () {
    global $wpdb; $wpdb->query("ALTER TABLE $wpdb-
   >posts ADD COLUMN digg_url varchar(128)"); }
 * add_action('deactivate_diggthis.php', 'diggurl_removecolumn');
 * function diggurl_removecolumn () {
    global $wpdb; $wpdb->query("ALTER TABLE $
   wpdb->posts DROP `digg_url`“); }
 * function show_digg_this () {
    $diggurl = $post->digg_url; $digg_permalink = the_permalink();
 * if ( strlen($diggurl) > 0 )
    echo ‘ $digg_url ‘ ;
 * else
    echo ‘ <div id=”digg_this_button”> <*a href=”[http://digg.com/submit?phase=2&url=$digg_permalink&#8221](http://digg.com/submit?phase=2&url=$digg_permalink&#8221);
   title=”Add to Digg”> <img src=”digg_button.gif” alt=”Digg Button” /> </div> ‘;}
 *  [yoshi](https://wordpress.org/support/users/yoshi/)
 * (@yoshi)
 * [19 years, 9 months ago](https://wordpress.org/support/topic/help-me-develop-a-plugin/#post-429319)
 * Oops. my show_digg_this() had error didn’t it. Sorry I wasn’t actually testing
   my code.
 * This time I checked this working.
 * `
    function show_digg_this ($id = 0) { global $post; // changed. $diggurl = $
   post->digg_url;
 * if ( strlen($diggurl) > 0 )
    echo $diggurl; else {
 * /* the_permalink() echos the url. use get_permalink() to get as valiable. */
   
   $digg_permalink = get_permalink($post->ID);
 * /* you can't use valiables within single quotes */
    echo '<div id="digg_this_button"
   ><a href="[http://digg.com/submit?phase=2&url=&#39](http://digg.com/submit?phase=2&url=&#39);.
   $digg_permalink . '" title="Add to Digg"><img src="digg_button.gif" alt="Digg
   Button" /></a> </div>'; } }
 *  [ehmcgregor](https://wordpress.org/support/users/ehmcgregor/)
 * (@ehmcgregor)
 * [19 years, 8 months ago](https://wordpress.org/support/topic/help-me-develop-a-plugin/#post-429398)
 * I’m having a hard time getting the add column to work. I really need to figure
   it out too! You link to two external php files in the add_action() function. 
   How does that work? I don’t have an activate / deactivate file. I’m a little 
   confused.
 * Yoshi, your comments are awesome! hopefully you can help me out. I’m really close.
   I just need to drop in an additional column like coolkarthik88. Maybe I don’t
   fully understand the add action function. I’ll go back and do some more reading.
 *  [ehmcgregor](https://wordpress.org/support/users/ehmcgregor/)
 * (@ehmcgregor)
 * [19 years, 8 months ago](https://wordpress.org/support/topic/help-me-develop-a-plugin/#post-429399)
 * yea, i just don’t understand why you have activate_diggthis.php? What is that?
   Why is that there. the API documentation says it needs to be a ‘hook’. Please
   help. Thanks.
 *  [yoshi](https://wordpress.org/support/users/yoshi/)
 * (@yoshi)
 * [19 years, 8 months ago](https://wordpress.org/support/topic/help-me-develop-a-plugin/#post-429408)
 * Hi ehmcgregor,
 * ‘activate_diggthis.php’ is not a external file but the ‘activate_’ hook, which
   is called when plugins are activated.
 * If your plugin file is myplugin.php, you can add action like:
 * `add_action('activate_myplugin.php','myplugin_install');`
 * then the function `myplugin_install()` will be executed on plugin activation.
   You can create column here.
 * And as you can guess, ‘disactivate_’ hook is for disactivation. You can remove
   some options or custom database table if needed.
 * Here is a list of wp hooks.
    [http://wphooks.flatearth.org/](http://wphooks.flatearth.org/)
 *  Thread Starter [coolkarthik88](https://wordpress.org/support/users/coolkarthik88/)
 * (@coolkarthik88)
 * [19 years, 8 months ago](https://wordpress.org/support/topic/help-me-develop-a-plugin/#post-429409)
 * hey yoshi.. how do I add an image to the HTML that the plugin generates. I want
   the image to be in the plugin folder…
 *  [yoshi](https://wordpress.org/support/users/yoshi/)
 * (@yoshi)
 * [19 years, 8 months ago](https://wordpress.org/support/topic/help-me-develop-a-plugin/#post-429411)
 * `<img src="<?php echo get_settings('siteurl') ?>/wp-content/plugins/myplugin/
   img.png" />`
 * Something like this?

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