match items inside curly braces and map them to a given string - php

Question

I am trying to make a routing system in php which uses regex. What I need is to match the route specified in route collection and check if the url matches with it, and if it does, return the parameters in the route by matching with the url.
For example
$route="user/{username}/id/{id}/age/{age}/profile";
$url="user/joe/id/99/age/33/profile";
First thing is to check if the $url matches the $route pattern, return false if it doesn't.
Then I need to return an array containing
[
'username'=>'joe',
'id'=>'99',
'age'=>'33',
]
I'm not good at this at all, I had a clumsy go at it.
Here's my current code
<?php
$r="user/username/{name}/id/{id}/age/{age}/profile";
$u="user/username/joe/id/99/age/33/profile";
route::match($r, $u);
class route{
public static function match($route, $url)
{
if(strpos($route, '{')===FALSE)
{
if(strcmp($route, $url)==0)
{
return TRUE;
}
return FALSE;
}
$vars=[];
$umatches=[];
preg_match_all('/\{(.*?)\}/', $route, $matches);
preg_match('/(.*?)\{/', $route, $amatches);
preg_match_all('/\}(.*?)\{/', $route, $bmatches);
$a=preg_split(end($bmatches[1]), $route);
$b=preg_split('/\}(.*?)/', $a[1]);
array_push($umatches, $amatches[1]);
foreach ($bmatches[1] as $key => $value)
{
array_push($umatches, $value);
}
array_push($umatches, $b[1]);
$pattern="/".str_replace('/', '\/', $amatches[1])."/";
$split=preg_split($pattern, $url);
$i=0;
foreach ($umatches as $key => $value) {
$value=str_replace('/', '\/', $value);
$value='/'.$value.'/';
$r=preg_split($value, $url);
$url=$r[1];
if($i>0)array_push($vars, $r[0]);
$i++;
}
print_r($vars);
if(sizeof($matches[1])!=sizeof($vars)) return FALSE;
$params=[];
for ($i=0; $i < sizeof($matches[1]); $i++) {
$params[$matches[1][$i]]=$vars[$i];
}
print_r($params);
return $params;
}
}
Here I ran the code http://ideone.com/blljFM

Answer 1

Not a php guru here. So below is just a quick 2-step solution using
pseudo-code.
global $TemplateArray;
global $UrlArray;
function GetRoutParams ( $strUrlTemplate, $strUrl )
{
$TemplateArray = [];
$UrlArray = [];
// Step 1. Create the regex from the template
$strUrlRegex = preg_replace_callback('~\{([^{}]+)\}~',
function( $matches ){
$repl = '([^/]+)';
// push $matches[1] into a $TemplateArray
return $repl;
},
$strUrlTemplate);
// Step 2. Create the hash from the regex
if ( preg_match($strUrlRegex, $strUrl, $matches) )
{
// Peel off the matches
// (Or, make a hash)
for ( int $i = 0; $i < $matches.count; $i++ )
{
push $UrlArray, $TemplateArray[$i];
push $UrlArray, $matches[$i];
}
// (Or, make a hash)
// $UrlHash[ $TemplateArray[$i] ] = $matches[$i];
}
else
{
return false;
}
return true;
}

Answer 2

Check out this regex with global match against your string:
(user|id|age)\/([^\/]+) it matches the keyword, a '/' and the next path element (which must not contain ANY '/'). Also be aware that for example a "superuser/1/" string would also be matched.
Each match should give you a key-value pair. Looping over the matches you can build your arrays/dicts as you intend.
<?php
$r="user/username/{name}/id/{id}/age/{age}/profile";
$u="user/username/joe/id/99/age/33/profile";
route::match($r, $u);
class route{
public static function match($route, $url)
{
preg_match_all('/(username|id|age)\/([^\/]+)/', $url, $matches);
$params=[];
for ($i=0; $i < sizeof($matches[1]); $i++) {
$params[$matches[1][$i]]=$matches[2][$i];
}
print_r($params);
return $params;
}
}
A little bit more elaborate:
<?php
$r=":user/username/[^/]+/id/[^/]+/age/[^/]+/profile:";
$u="user/username/joe/id/99/age/33/profile";
$k="username|id|age"; # valid keys
print_r(route::match($r, $u, $k));
class route{
public static function match($route, $url, $valid_url_keys)
{
$number_of_expected_key_value_pairs = 3;
$number_of_matches = preg_match_all(":($valid_url_keys)/([^/]+):", $url, $matches);
if($number_of_matches == $number_of_expected_key_value_pairs)
{
$params=[];
for ($i=0; $i < sizeof($matches[1]); $i++) {
$params[$matches[1][$i]]=$matches[2][$i];
}
return $params;
}
else {
return FALSE;
}
}
}
Changed regex delimiter to colon, since the slash is a url-pattern, we need less escaping.
Only returns matches if they match the route specification.

Answer 3

Update: I've implemented sln's solution with a few fixes. Here's it
class Route
{
private static $tmp = array();
public static function GetRoutParams($strUrlTemplate, $strUrl)
{
$strUrlRegex = preg_replace_callback('~\{([^{}]+)\}~',
function ($matches)
{
$repl = '([^)]+)';
self::$tmp[] = $matches[1];
return $repl;
}
, $strUrlTemplate);
$UrlArray = array();
$matches = array();
$strUrlRegex = str_replace('/', '\/', $strUrlRegex);
if (preg_match("/^" . $strUrlRegex . "$/", $strUrl, $matches))
{
for ($i = 0; $i < count(self::$tmp); $i++)
{
$UrlArray[self::$tmp[$i]] = $matches[$i + 1];
}
self::$tmp = array();
return $UrlArray;
}
return false;
}
}
I've completed the code; though it feels inefficient. I'd be grateful if someone helps making the code more efficient.
<?php
$route = "user/{name}/id/{id}/age/{age}/ash";
$url = "user/joe/id/99/age/33/ash";
route::match($route, $url);
class route
{
public static function match($route, $url)
{
if (strpos($route, '{') === FALSE)
{
if (strcmp($route, $url) == 0)
{
return TRUE;
}
return FALSE;
}
$vars = [];
$umatches = [];
//get all parameters in curly braces in $route
preg_match_all('/\{(.*?)\}/', $route, $matches);
//get the string before first occurrence of { in $route
preg_match('/(.*?)\{/', $route, $amatches);
//get all strings between } and { in $route
preg_match_all('/\}(.*?)\{/', $route, $bmatches);
//get the string after last }
if (!empty($bmatches[1])){
$a = preg_split(end($bmatches[1]) , $route);
$b = preg_split('/\}(.*?)/', end($a));
}
else{
$a = preg_split('/' . str_replace('/', '\/', end($amatches)) . '/', $route);
$b = preg_split('/\}(.*?)/', end($a));
}
//push the matches into array $umatches
if (!empty($amatches[1])) array_push($umatches, $amatches[1]);
if (!empty($bmatches[1]))
{
foreach($bmatches[1] as $key => $value)
{
array_push($umatches, $value);
}
}
if (!empty($b[1])) array_push($umatches, $b[1]);
//check if the $url matches with $route template
$prev = - 1;
foreach($umatches as $key => $value)
{
$pos = strpos($url, $value);
if ($pos !== FALSE)
{
if ($prev > $pos) return FALSE;
$prev = $pos;
}
else return FALSE;
}
//push the parameter values in $url into $vars array
$i = 0;
foreach($umatches as $key => $value)
{
$value = str_replace('/', '\/', $value);
$value = '/' . $value . '/';
$r = preg_split($value, $url);
$url = $r[1];
if (!empty($r[0])) array_push($vars, $r[0]);
$i++;
}
if (!empty($r[1])) array_push($vars, $r[1]);
//map the values in $url with the parameters in $route template
$params = [];
for ($i = 0; $i < sizeof($matches[1]); $i++)
{
$params[$matches[1][$i]] = $vars[$i];
}
return $params;
}
}
The code now properly returns the parameters. The problems I had was the code was being preg_split by empty strings in some places. Also I didn't push the value if the parameter occurred in the end of string; for example - user/{username}, here {username} wasn't being pushed properly. Also the comparing the template with given url using sizeof() doesn't always give correct result.