144 lines
4.5 KiB
Markdown
144 lines
4.5 KiB
Markdown
---
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nav: blog
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title: Creating and using custom tokens in Drupal 7
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slug: creating-and-using-custom-tokens-drupal-7
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tags:
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- drupal
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- drupal-planet
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- drupal-7
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- tokens
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---
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{% block excerpt %}
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This post outlines the steps required to create your own custom tokens in Drupal.
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{% endblock %}
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{% block content %}
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This post outlines the steps required to create your own custom tokens in Drupal.
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When writing the recent releases of the [Copyright Block](http://drupal.org/project/copyright_block) module, I used tokens to allow the user to edit and customise their copyright message and place the copyright_message:dates token in the desired position. When the block is rendered, the token is replaced by the necessary dates.
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We will be using the fictional *foo* module to demonstrate this.
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## Requirements
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* [Token module](http://drupal.org/project/token)
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## Recommended
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* [Devel module](http://drupal.org/project/devel) - useful to run `dpm()` and `kpr()` functions
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* [Copyright Block module](http://drupal.org/project/copyright_block) - 7.x-2.x and 6.x-1.x use tokens, handy as a reference
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## Implementing hook_token_info()
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The first thing that we need to do is define the new token type and/or the token itself, along with it's descriptive text. To view the existing tokens and types, use `dpm(token_get_info());`, assuming that you have the [Devel module](http://drupal.org/project/devel) installed.
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~~~php
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/**
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* Implements hook_token_info().
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*/
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function foo_token_info() {
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$info = array();
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// Add any new tokens.
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$info['tokens']['foo']['bar'] = t('This is my new bar token within the foo type.');
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// Return them.
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return $info;
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}
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~~~
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In this case, the token called *bar* resides within the *foo* group.
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If I needed to add a new token within an existing token type, such as 'node', the syntax would be `$info['tokens']['node']['bar']`.
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## Implementing hook_tokens()
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Now that the Token module is aware of our new token, we now need to determine what the token is replaced with. This is done using `hook_tokens()`. Here is the basic code needed for an implementation:
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~~~php
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/**
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* Implements hook_tokens().
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*/
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function foo_tokens($type, $tokens, array $data = array(), array $options = array()) {
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$replacements = array();
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// Code goes here...
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// Return the replacements.
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return $replacements;
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}
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~~~
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The first thing to check for is the type of token using an `if()` function, as this could be an existing type like 'node', 'user' or 'site', or a custom token type like 'foo'. Once we're sure that we're looking at the right type(s), we can use `foreach ($tokens as $name => $original)` to loop through each of the available tokens using a `switch()`. For each token, you can perform some logic to work out the replacement text and then add it into the replacements array using `$replacements[$original] = $new;`.
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~~~php
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/**
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* Implements hook_tokens().
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*/
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function foo_tokens($type, $tokens, array $data = array(), array $options = array()) {
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$replacements = array();
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// The first thing that we're going to check for is the type of token - node,
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// user etc...
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if ($type == 'foo') {
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// Loop through each of the available tokens.
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foreach ($tokens as $name => $original) {
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// Find the desired token by name
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switch ($name) {
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case 'bar':
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$new = '';
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// Work out the value of $new...
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// Add the new value into the replacements array.
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$replacements[$original] = $new;
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break;
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}
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}
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}
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// Return the replacements.
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return $replacements;
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}
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~~~
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## Example
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An example from Copyright Block module:
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~~~php
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/**
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* Implements hook_tokens().
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*/
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function copyright_block_tokens($type, $tokens, array $data = array(), array $options = array()) {
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$replacements = array();
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if ($type == 'copyright_statement') {
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foreach ($tokens as $name => $original) {
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switch ($name) {
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case 'dates':
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$start_year = variable_get('copyright_block_start_year', date('Y'));
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$current_year = date('Y');
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$replacements[$original] = $start_year < $current_year ? $start_year . '-' . $current_year : $start_year;
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break;
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}
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}
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}
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return $replacements;
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}
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~~~
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## Using token_replace()
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With everything defined, all that we now need to do is pass some text through the `token_replace()` function to replace it with the values defined within `hook_token()`.
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~~~php
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$a = t('Something');
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// This would use any token type - node, user etc.
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$b = token_replace($a);
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// This would only use foo tokens.
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$c = token_replace($a, array('foo'));
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~~~
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{% endblock %}
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