<?php
# unparse_url.php - Inverse of parse_url
# Version 0.1  Sun, 25 Jun 2006 17:06:02 -0600
#
# Copyright (C) 2006  Dwayne C. Litzenberger <dlitz@dlitz.net>
# 
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

# This function is indended to be the inverse of parse_url, with some sanity
# checks against RFC 3986.

function unparse_url($parts, $loose=FALSE) 
{
    $p_scheme = @$parts['scheme'];
    $p_host = @$parts['host'];
    $p_port = @$parts['port'];
    $p_user = @$parts['user'];
    $p_pass = @$parts['pass'];
    $p_path = @$parts['path'];
    $p_query = @$parts['query'];
    $p_fragment = @$parts['fragment'];
    
    if (!$loose) {
        $dec_octet = '(?:\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5])';
        $IPv4address = "(?:$dec_octet\\.$dec_octet\\.$dec_octet\\.$dec_octet)";
        $h16 = '(?:[[:xdigit:]]{1,4})';
        $ls32 = '(?:'.$h16.':'.$h16.'|'.$IPv4address.')';
        $IPv6address = "(?:".
                                     "(?:$h16:){6}$ls32|".
                                   "::(?:$h16:){5}$ls32|".
                              "$h16?::(?:$h16:){4}$ls32|".
            "(?:(?:$h16:){0,1}$h16)?::(?:$h16:){3}$ls32|".
            "(?:(?:$h16:){0,2}$h16)?::(?:$h16:){2}$ls32|".
            "(?:(?:$h16:){0,3}$h16)?::(?:$h16:){1}$ls32|".
            "(?:(?:$h16:){0,4}$h16)?::" .        "$ls32|".
            "(?:(?:$h16:){0,5}$h16)?::" .        "$h16|".
            "(?:(?:$h16:){0,6}$h16)?::".
            ")";

        $unreserved = '[[:alpha:]\d\-\._~]';
        $sub_delims = "[!\$&'()\*\+,;=]";
        $IPvFuture = "(?:v[[:xdigit:]]+\\.[$unreserved$sub_delims\\:]+)";
        $IP_literal = "(?:\\[(?:$IPv6address|$IPvFuture)\\])";
        $pct_encoded = "(?:%[[:xdigit:]]{2})";
        $reg_name = "(?:$unreserved|$pct_encoded|$sub_delims)*";
        $pchar = "(?:$unreserved|$pct_encoded|$sub_delims|\:@)";
        $segment = "$pchar*";
        $segment_nz = "$pchar+";
        $path_absolute = "(?:/(?:$segment_nz(?:/$segment)*)?)";
        $path_rootless = "$segment_nz(?:/$segment)*";
        
        # Validate the scheme part
        #  scheme        = ALPHA *( ALPHA / DIGIT / "+" / "-" / "." )
        # NB: "file" is hard-coded in PHP
        if (isset($p_scheme) and 
            !preg_match('|^[[:alpha:]][[:alpha:]\d\+\-\.]*$|s', $p_scheme))
        {
            trigger_error('Illegal URI scheme', E_USER_WARNING);
            return FALSE;
        }
        
        # Validate the host part
        if (isset($p_host) and 
            !preg_match("#^(?:$IP_literal|$IPv4address|$reg_name)\$#s",
                $p_host))
        {
            trigger_error('Illegal host part', E_USER_WARNING);
            return FALSE;
        }
        
        # Validate the port part
        if (isset($p_port) and
            !preg_match("#^\d*\$#s", $p_port))
        {
            trigger_error('Illegal port part', E_USER_WARNING);
            return FALSE;
        }    
        
        # Validate the user part
        if (isset($p_user) and
            !preg_match("#^(?:$unreserved|$pct_encoded|$sub_delims)*\$#s",
                $p_user))
        {
            trigger_error('Illegal user part', E_USER_WARNING);
            return FALSE;
        }
        
        # Validate the password part
        if (isset($p_pass) and
            !preg_match("#^(?:$unreserved|$pct_encoded|$sub_delims|:)*\$#s",
                $p_pass))
        {
            trigger_error('Illegal pass part', E_USER_WARNING);
            return FALSE;
        }    
        
        # Validate the path part
        if (isset($p_path) and
            !preg_match("#^$path_absolute|$path_rootless\$#s", $p_path))
        {
            trigger_error('Illegal path part', E_USER_WARNING);
            return FALSE;
        }    
     
        # Validate the query part
        if (isset($p_query) and
            !preg_match("#^(?:$pchar|/|\?)*\$#s", $p_query))
        {
            trigger_error('Illegal query part', E_USER_WARNING);
            return FALSE;
        }    
         
        # Validate the fragment part
        if (isset($p_fragment) and
            !preg_match("#^(?:$pchar|/|\?)*\$#s", $p_fragment))
        {
            trigger_error('Illegal fragment part', E_USER_WARNING);
            return FALSE;
        }    
    }

    # Build the URI
    $retval = "";
    if (isset($p_scheme)) {
        $retval = $p_scheme . ":";
        if (strtolower($p_scheme) == "file" and !isset($p_host)) {
            $retval .= "//";
        }
    }
    if (isset($p_host)) {
        $retval .= "//";
        if (isset($p_user) or isset($p_pass)) {
            $retval .= isset($p_user) ? $p_user : "";
            $retval .= isset($p_pass) ? ":" . $p_pass : "";
            $retval .= '@';
        }
        $retval .= $p_host;
        if (isset($p_port)) {
            $retval .= ':' . $p_port;
        }
    }
    if (isset($p_path)) {
        $retval .= $p_path;
    }
    if (isset($p_query)) {
        $retval .= '?' . $p_query;
    }
    if (isset($p_fragment)) {
        $retval .= '#' . $p_fragment;
    }
    return $retval;
}

/* vim:set ts=4 sw=4 sts=4 expandtab: */