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<?php
/**
* @file
* Drupal placeholder/token replacement system.
*
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* API functions for replacing placeholders in text with meaningful values.
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*
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* For example: When configuring automated emails, an administrator enters
* standard text for the email. Variables like the title of a node and the date
* the email was sent can be entered as placeholders like [node:title] and
* [date:short]. When a Drupal module prepares to send the email, it can call
* the token_replace() function, passing in the text. The token system will
* scan the text for placeholder tokens, give other modules an opportunity to
* replace them with meaningful text, then return the final product to the
* original module.
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*
* Tokens follow the form: [$type:$name], where $type is a general class of
* tokens like 'node', 'user', or 'comment' and $name is the name of a given
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* placeholder. For example, [node:title] or [node:created:since].
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*
* In addition to raw text containing placeholders, modules may pass in an array
* of objects to be used when performing the replacement. The objects should be
* keyed by the token type they correspond to. For example:
*
* @code
* // Load a node and a user, then replace tokens in the text.
* $text = 'On [date:short], [user:name] read [node:title].';
* $node = node_load(1);
* $user = user_load(1);
*
* // [date:...] tokens use the current date automatically.
* $data = array('node' => $node, 'user' => $user);
* return token_replace($text, $data);
* @endcode
*
* Some tokens may be chained in the form of [$type:$pointer:$name], where $type
* is a normal token type, $pointer is a reference to another token type, and
* $name is the name of a given placeholder. For example, [node:author:mail]. In
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* that example, 'author' is a pointer to the 'user' account that created the
* node, and 'mail' is a placeholder available for any 'user'.
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*
* @see token_replace()
* @see hook_tokens()
* @see hook_token_info()
*/
/**
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* Replaces all tokens in a given string with appropriate values.
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*
* @param $text
* A string potentially containing replaceable tokens.
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* @param $data
* (optional) An array of keyed objects. For simple replacement scenarios
* 'node', 'user', and others are common keys, with an accompanying node or
* user object being the value. Some token types, like 'site', do not require
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* any explicit information from $data and can be replaced even if it is
* empty.
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* @param $options
* (optional) A keyed array of settings and flags to control the token
* replacement process. Supported options are:
* - language: A language object to be used when generating locale-sensitive
* tokens.
* - callback: A callback function that will be used to post-process the array
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* of token replacements after they are generated. For example, a module
* using tokens in a text-only email might provide a callback to strip HTML
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* entities from token values before they are inserted into the final text.
* - clear: A boolean flag indicating that tokens should be removed from the
* final text if no replacement value can be generated.
* - sanitize: A boolean flag indicating that tokens should be sanitized for
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* display to a web browser. Defaults to TRUE. Developers who set this
* option to FALSE assume responsibility for running filter_xss(),
* check_plain() or other appropriate scrubbing functions before displaying
* data to users.
*
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* @return
* Text with tokens replaced.
*/
function token_replace($text, array $data = array(), array $options = array()) {
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$text_tokens = token_scan($text);
if (empty($text_tokens)) {
return $text;
}
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$replacements = array();
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foreach ($text_tokens as $type => $tokens) {
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$replacements += token_generate($type, $tokens, $data, $options);
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if (!empty($options['clear'])) {
$replacements += array_fill_keys($tokens, '');
}
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}
// Optionally alter the list of replacement values.
if (!empty($options['callback']) && function_exists($options['callback'])) {
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$function = $options['callback'];
$function($replacements, $data, $options);
}
$tokens = array_keys($replacements);
$values = array_values($replacements);
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return str_replace($tokens, $values, $text);
}
/**
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* Builds a list of all token-like patterns that appear in the text.
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*
* @param $text
* The text to be scanned for possible tokens.
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*
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* @return
* An associative array of discovered tokens, grouped by type.
*/
function token_scan($text) {
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// Matches tokens with the following pattern: [$type:$name]
// $type and $name may not contain [ ] or whitespace characters.
// $type may not contain : characters, but $name may.
preg_match_all('/
\[ # [ - pattern start
([^\s\[\]:]*) # match $type not containing whitespace : [ or ]
: # : - separator
([^\s\[\]]*) # match $name not containing whitespace [ or ]
\] # ] - pattern end
/x', $text, $matches);
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$types = $matches[1];
$tokens = $matches[2];
// Iterate through the matches, building an associative array containing
// $tokens grouped by $types, pointing to the version of the token found in
// the source text. For example, $results['node']['title'] = '[node:title]';
$results = array();
for ($i = 0; $i < count($tokens); $i++) {
$results[$types[$i]][$tokens[$i]] = $matches[0][$i];
}
return $results;
}
/**
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* Generates replacement values for a list of tokens.
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*
* @param $type
* The type of token being replaced. 'node', 'user', and 'date' are common.
* @param $tokens
* An array of tokens to be replaced, keyed by the literal text of the token
* as it appeared in the source text.
* @param $data
* (optional) An array of keyed objects. For simple replacement scenarios
* 'node', 'user', and others are common keys, with an accompanying node or
* user object being the value. Some token types, like 'site', do not require
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* any explicit information from $data and can be replaced even if it is
* empty.
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* @param $options
* (optional) A keyed array of settings and flags to control the token
* replacement process. Supported options are:
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* - language: A language object to be used when generating locale-sensitive
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* tokens.
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* - callback: A callback function that will be used to post-process the
* array of token replacements after they are generated. Can be used when
* modules require special formatting of token text, for example URL
* encoding or truncation to a specific length.
* - sanitize: A boolean flag indicating that tokens should be sanitized for
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* display to a web browser. Developers who set this option to FALSE assume
* responsibility for running filter_xss(), check_plain() or other
* appropriate scrubbing functions before displaying data to users.
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*
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* @return
* An associative array of replacement values, keyed by the original 'raw'
* tokens that were found in the source text. For example:
* $results['[node:title]'] = 'My new node';
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*
* @see hook_tokens()
* @see hook_tokens_alter()
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*/
function token_generate($type, array $tokens, array $data = array(), array $options = array()) {
$options += array('sanitize' => TRUE);
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$replacements = module_invoke_all('tokens', $type, $tokens, $data, $options);
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// Allow other modules to alter the replacements.
$context = array(
'type' => $type,
'tokens' => $tokens,
'data' => $data,
'options' => $options,
);
drupal_alter('tokens', $replacements, $context);
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return $replacements;
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}
/**
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* Given a list of tokens, returns those that begin with a specific prefix.
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*
* Used to extract a group of 'chained' tokens (such as [node:author:name]) from
* the full list of tokens found in text. For example:
* @code
* $data = array(
* 'author:name' => '[node:author:name]',
* 'title' => '[node:title]',
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* 'created' => '[node:created]',
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* );
* $results = token_find_with_prefix($data, 'author');
* $results == array('name' => '[node:author:name]');
* @endcode
*
* @param $tokens
* A keyed array of tokens, and their original raw form in the source text.
* @param $prefix
* A textual string to be matched at the beginning of the token.
* @param $delimiter
* An optional string containing the character that separates the prefix from
* the rest of the token. Defaults to ':'.
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*
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* @return
* An associative array of discovered tokens, with the prefix and delimiter
* stripped from the key.
*/
function token_find_with_prefix(array $tokens, $prefix, $delimiter = ':') {
$results = array();
foreach ($tokens as $token => $raw) {
$parts = explode($delimiter, $token, 2);
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if (count($parts) == 2 && $parts[0] == $prefix) {
$results[$parts[1]] = $raw;
}
}
return $results;
}
/**
* Returns metadata describing supported tokens.
*
* The metadata array contains token type, name, and description data as well as
* an optional pointer indicating that the token chains to another set of tokens.
* For example:
* @code
* $data['types']['node'] = array(
* 'name' => t('Nodes'),
* 'description' => t('Tokens related to node objects.'),
* );
* $data['tokens']['node']['title'] = array(
* 'name' => t('Title'),
* 'description' => t('The title of the current node.'),
* );
* $data['tokens']['node']['author'] = array(
* 'name' => t('Author'),
* 'description' => t('The author of the current node.'),
* 'type' => 'user',
* );
* @endcode
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*
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* @return
* An associative array of token information, grouped by token type.
*/
function token_info() {
$data = &drupal_static(__FUNCTION__);
if (!isset($data)) {
$data = module_invoke_all('token_info');
drupal_alter('token_info', $data);
}
return $data;
}