<?php
namespace Guzzle\Parser\UriTemplate;
/**
* Expands URI templates using an array of variables
*
* @link http://tools.ietf.org/html/draft-gregorio-uritemplate-08
*/
class UriTemplate implements UriTemplateInterface
{
const DEFAULT_PATTERN = '/\{([^\}]+)\}/';
/** @var string URI template */
private $template;
/** @var array Variables to use in the template expansion */
private $variables;
/** @var string Regex used to parse expressions */
private $regex = self::DEFAULT_PATTERN;
/** @var array Hash for quick operator lookups */
private static $operatorHash = array(
'+' => true, '#' => true, '.' => true, '/' => true, ';' => true, '?' => true, '&' => true
);
/** @var array Delimiters */
private static $delims = array(
':', '/', '?', '#', '[', ']', '@', '!', '$', '&', '\'', '(', ')', '*', '+', ',', ';', '='
);
/** @var array Percent encoded delimiters */
private static $delimsPct = array(
'%3A', '%2F', '%3F', '%23', '%5B', '%5D', '%40', '%21', '%24', '%26', '%27', '%28', '%29', '%2A', '%2B', '%2C',
'%3B', '%3D'
);
public function expand($template, array $variables)
{
if ($this->regex == self::DEFAULT_PATTERN && false === strpos($template, '{')) {
return $template;
}
$this->template = $template;
$this->variables = $variables;
return preg_replace_callback($this->regex, array($this, 'expandMatch'), $this->template);
}
/**
* Set the regex patten used to expand URI templates
*
* @param string $regexPattern
*/
public function setRegex($regexPattern)
{
$this->regex = $regexPattern;
}
/**
* Parse an expression into parts
*
* @param string $expression Expression to parse
*
* @return array Returns an associative array of parts
*/
private function parseExpression($expression)
{
// Check for URI operators
$operator = '';
if (isset(self::$operatorHash[$expression[0]])) {
$operator = $expression[0];
$expression = substr($expression, 1);
}
$values = explode(',', $expression);
foreach ($values as &$value) {
$value = trim($value);
$varspec = array();
$substrPos = strpos($value, ':');
if ($substrPos) {
$varspec['value'] = substr($value, 0, $substrPos);
$varspec['modifier'] = ':';
$varspec['position'] = (int) substr($value, $substrPos + 1);
} elseif (substr($value, -1) == '*') {
$varspec['modifier'] = '*';
$varspec['value'] = substr($value, 0, -1);
} else {
$varspec['value'] = (string) $value;
$varspec['modifier'] = '';
}
$value = $varspec;
}
return array(
'operator' => $operator,
'values' => $values
);
}
/**
* Process an expansion
*
* @param array $matches Matches met in the preg_replace_callback
*
* @return string Returns the replacement string
*/
private function expandMatch(array $matches)
{
static $rfc1738to3986 = array(
'+' => '%20',
'%7e' => '~'
);
$parsed = self::parseExpression($matches[1]);
$replacements = array();
$prefix = $parsed['operator'];
$joiner = $parsed['operator'];
$useQueryString = false;
if ($parsed['operator'] == '?') {
$joiner = '&';
$useQueryString = true;
} elseif ($parsed['operator'] == '&') {
$useQueryString = true;
} elseif ($parsed['operator'] == '#') {
$joiner = ',';
} elseif ($parsed['operator'] == ';') {
$useQueryString = true;
} elseif ($parsed['operator'] == '' || $parsed['operator'] == '+') {
$joiner = ',';
$prefix = '';
}
foreach ($parsed['values'] as $value) {
if (!array_key_exists($value['value'], $this->variables) || $this->variables[$value['value']] === null) {
continue;
}
$variable = $this->variables[$value['value']];
$actuallyUseQueryString = $useQueryString;
$expanded = '';
if (is_array($variable)) {
$isAssoc = $this->isAssoc($variable);
$kvp = array();
foreach ($variable as $key => $var) {
if ($isAssoc) {
$key = rawurlencode($key);
$isNestedArray = is_array($var);
} else {
$isNestedArray = false;
}
if (!$isNestedArray) {
$var = rawurlencode($var);
if ($parsed['operator'] == '+' || $parsed['operator'] == '#') {
$var = $this->decodeReserved($var);
}
}
if ($value['modifier'] == '*') {
if ($isAssoc) {
if ($isNestedArray) {
// Nested arrays must allow for deeply nested structures
$var = strtr(http_build_query(array($key => $var)), $rfc1738to3986);
} else {
$var = $key . '=' . $var;
}
} elseif ($key > 0 && $actuallyUseQueryString) {
$var = $value['value'] . '=' . $var;
}
}
$kvp[$key] = $var;
}
if (empty($variable)) {
$actuallyUseQueryString = false;
} elseif ($value['modifier'] == '*') {
$expanded = implode($joiner, $kvp);
if ($isAssoc) {
// Don't prepend the value name when using the explode modifier with an associative array
$actuallyUseQueryString = false;
}
} else {
if ($isAssoc) {
// When an associative array is encountered and the explode modifier is not set, then the
// result must be a comma separated list of keys followed by their respective values.
foreach ($kvp as $k => &$v) {
$v = $k . ',' . $v;
}
}
$expanded = implode(',', $kvp);
}
} else {
if ($value['modifier'] == ':') {
$variable = substr($variable, 0, $value['position']);
}
$expanded = rawurlencode($variable);
if ($parsed['operator'] == '+' || $parsed['operator'] == '#') {
$expanded = $this->decodeReserved($expanded);
}
}
if ($actuallyUseQueryString) {
if (!$expanded && $joiner != '&') {
$expanded = $value['value'];
} else {
$expanded = $value['value'] . '=' . $expanded;
}
}
$replacements[] = $expanded;
}
$ret = implode($joiner, $replacements);
if ($ret && $prefix) {
return $prefix . $ret;
}
return $ret;
}
/**
* Determines if an array is associative
*
* @param array $array Array to check
*
* @return bool
*/
private function isAssoc(array $array)
{
return (bool) count(array_filter(array_keys($array), 'is_string'));
}
/**
* Removes percent encoding on reserved characters (used with + and # modifiers)
*
* @param string $string String to fix
*
* @return string
*/
private function decodeReserved($string)
{
return str_replace(self::$delimsPct, self::$delims, $string);
}
}