Im very new to WordPress. I was going through Smooth Slider WP Plugin and saw
if ( function_exists( 'get_smooth_slider_category' ) ) { get_smooth_slider_category('Uncategorized'); }
This pretty much gives what I wanted, but not quite. This pulls all the content in the category and what Im after is just the image URL.
My question is whats "function_exists" in wordpress? and I checked get_smooth_slider_category in functions.php file but couldnt find any. Can someone please explain how function_exists works?
function_exists is a PHP function, not limited to WordPress.
From the manual "Checks the list of defined functions, both built-in (internal) and user-defined, for function_name."
It returns true or false on whether or not the function exists. So you can either create a new function before it that does something slightly different, or prevent an error if it doesn't exist (normally because the required file hasn't been included).
This is a PHP function that checks if the passed in name matches any defined functions (either internal, or user defined).
It is a way to check if a function is "available" before calling it.
Related
I'm new to WP development. I need to write a hook to check if the currently logged in user is viewing a post listed within a specific category, and then redirect user if they're lacking certain meta data.
I tried creating this function:
add_action('init','check_user_post_category');
however inside that function I was unable to get the post object (I have tried everything I found on the web!)
global $post; // This object is not valid at this time
global $wp; // $wp->request is empty
$_REQUEST; // This var is giving me an empty array! Is this normal??? :(
Could you kindly suggest, what hook is best to use in this case, and how to get the post object? Many thanks!
Use 'wp' hook instead of 'init'.
add_action('wp','check_user_post_category');
Maybe this would work for you.
I'm defining plugin path as a constant through constant define method as shown below.
define( 'MY_PLUGIN_DIR', untrailingslashit( plugin_dir_path( __FILE__ ) ) );
It is accessible within plugin all files and themes. But when I call this constant in another plugin this constant becomes undefined.
How I can get this plugin constant in another plugin? Any help will be appreciated.
Thanks,
Probably your problem is the order that wordpress is calling your plugins: the plugins that sets the constant is loaded after the one who calls it.
A better explanation of how to force your plugin be loaded first can be found here. I'm putting here a quote of the part that matters:
The order that plugins are loaded (as of WP 2.9.1 at least) is determined by the order of an array stored as "active_plugins" in the WP options table. Whenever a plugin is activated, it is added to this array, the array is sorted alphabetically by plugin name, and the array is saved to the DB.
Fortunately, there is a convenient action hook, "activated_plugins", that is called after the active plugins array is saved to the DB. This allows you to manipulate the order of the plugins stored in this array after the array is initially saved.
You'll have to the following PHP code in the plugin who defines the constant, then deactivate and reactivate it (copied from the link I providaded above).
function this_plugin_first() {
// ensure path to this file is via main wp plugin path
$wp_path_to_this_file = preg_replace('/(.*)plugins\/(.*)$/', WP_PLUGIN_DIR."/$2", __FILE__);
$this_plugin = plugin_basename(trim($wp_path_to_this_file));
$active_plugins = get_option('active_plugins');
$this_plugin_key = array_search($this_plugin, $active_plugins);
if ($this_plugin_key) { // if it's 0 it's the first plugin already, no need to continue
array_splice($active_plugins, $this_plugin_key, 1);
array_unshift($active_plugins, $this_plugin);
update_option('active_plugins', $active_plugins);
}
}
add_action("activated_plugin", "this_plugin_first");
Hope it helps!
I have been trying to associate CUSTOM data to each of my WP POSTS using the following piece of code :
if($condition === true){
if ( ! update_post_meta ($post_id, '_someData', $someVariable) ) {
add_post_meta($post_id, '_someData', $someVariable);
}
}
However, seems like the META VALUE is RESET to default i.e. Zero OR Blank. Our WordPress website has around 40 plugins, and I think one of these WordPress plugins, is coming in my way of doing things. All of my logic works fine, on a demo WordPres website. Is there a way for me to have total control to set the META Value for a given POST ? Also, is there a way where I can be notified that the META Key is about to change and then I can decide whether OR not to change the Meta Value ?
Any pointers or reference URL's can be of great help. Thanks !
You only need to call update_post_meta in either scenario. Calling add_post_meta() is not necessary and could be causing this problem.
From the codex:
The function update_post_meta() updates the value of an existing meta key (custom field) for the specified post.
This may be used in place of add_post_meta() function. The first thing this function will do is make sure that $meta_key already exists on $post_id. If it does not, add_post_meta($post_id, $meta_key, $meta_value) is called instead and its result is returned.
As I have started learning wordpress plugin developement recently but i can't understand the function __return_empty_array. It returns an array but when should we really use it.
__return_empty_array returns an empty array. It is ued to return empty array to filters. For example consider the case of turning off the link of the authors page. You can add the following code to functions.php to get it done.
add_filter ('author_rewrite_rules', '__return_empty_array');
In this case an empty array is returned and __return_empty_array is used for it. Hope you get me.
I want to set custom php variables that can be used throughout my drupal theme (html.tpl.php, page.tpl.php etc.) I need the variables set based on the $title of the node. I'm not an expert on how Drupal works, the moduling and hooks, and I just need to know the simplest/easiest way to accomplish this. I keep reading about implementing some sort of hook in the template.php file where you can set variables, but I've been unsuccesful with everything I've tried.
So, basically, how would you accomplish this:
Get $title of Node
Set variables that will be passed along into theme files (for example, to do basic things like: if($title == 'news_page') { $siteSection = "news"; } )
Have $siteSection be available to use in theme files
Any help would be great.. thanks!
Before Drupal builds the HTML for a page from a theme's template (.tpl.php file), it runs preprocess "hooks". Hooks are basically a naming convention for functions that let modules and themes override or "hook" onto Drupal core processes.
E.g., if you want to display a message to a user when they log in, you can use hook_user_login.
function MODULENAME_user_login(&$edit, $account) {
drupal_set_message("Welcome, ". $account->name);
}
When a user logs in, Drupal looks for all loaded functions that end in "_user_login" and it runs them. If this function is in an enabled module, it has been loaded, so it will get run as well.
If you want to make a variable named $site_section available in your page.tpl.php file, you can hook into template_preprocess_page. This is a theme hook, so the name is a little different, but it functions pretty much the same way. To call this hook from your theme, you need to create a file called template.php in your theme's directory. Inside template.php, we'll add:
<?php
function THEMENAME_preprocess_page(&$vars){
switch (drupal_strtolower($vars['node']->title)) {
case "about page":
$site_section = "about";
break;
case "news page":
case "news page1":
case "news page2":
$site_section = "news";
break;
default:
$site_section = "none";
break;
}
$vars['site_section'] = $site_section;
}
The <?php is used to tell the server the treat all of the proceeding code as PHP. We then declare our hook function with the intention of loading Drupal's array of page variables into a local variable called $vars. By adding the & before $vars, we'll be allowed to modify the values for use outside of this function.
The switch statement will let us efficiently test the page title for multiple values. The value of the node's title may contain uppercase letters, lowercase letters, and symbols, so to avoid a case-sensitive mismatch, we're going to convert the title to lowercase and only test that (symbols will still be in the title, though). After the switch statement, we set the value of our $site_section local value into the referenced $vars array for use in page.tpl.php.
However, if it's just your intention to break the site up into sections for theming purposes, there are other ways of accomplishing that. My answer to a similar situation a few months ago might be helpful.