A lax Web news feed parser
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<?php
/** @license MIT
* Copyright 2018 J. King et al.
* See LICENSE and AUTHORS files for details */
declare(strict_types=1);
namespace MensBeam\Lax;
use Psr\Http\Message\UriInterface;
/** Normalized URI representation, compatible with the PSR-7 URI interface
*
* The following features are implemented:
*
* - The full PSR-7 `UriInterface` interface
* - Correct handling of both URLs and URNs
* - Relative URL resolution
* - Encoding normalization
* - Scheme normalization
* - IDNA normalization
* - IPv6 address normalization
* - Empty query and fragment removal
*
* Some things this class does not do:
*
* - Handle non-standard schemes (e.g. ed2k)
* - Collapse paths
* - Drop default ports
*
* This class should not be used with XML namespace URIs,
* as the normalizations performed will change the values
* of some namespaces.
*/
class Url implements UriInterface {
protected const URI_PATTERN = <<<'PCRE'
<^
(?:
(?:
([a-z][a-z0-9\.\-\+]*): | # absolute URI
:?(?=//) # scheme-relative URI
)
(//[^/\?\#]*)? # authority part
)?
([^\?\#]*) # path part
(\?[^\#]*)? # query part
(\#.*)? # fragment part
$>six
PCRE;
protected const HOST_PATTERN = '/^(\[[a-f0-9:]*\]|[^:]*)(?::([^\/]*))?$/si';
protected const USER_PATTERN = '/^([^:]*)(?::(.*))?$/s';
protected const SCHEME_PATTERN = '/^(?:[a-z][a-z0-9\.\-\+]*|)$/i';
protected const IPV6_PATTERN = '/^\[[a-f0-9:]+\]$/i';
protected const PORT_PATTERN = '/^\d*$/';
protected const FORBIDDEN_HOST_PATTERN = '/[\x{00}\t\n\r #%\/:\?@\[\]\\\]/';
protected const WHITESPACE_CHARS = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A\x0B\x0C\x0D\x0E\x0F\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1A\x1B\x1C\x1D\x1E\x1F\x20";
protected const ESCAPE_CHARS = [
'user' => [":", "@", "/", "?", "#"],
'pass' => [":", "@", "/", "?", "#"],
'path' => ["?", "#"],
'query' => ["#"],
];
protected const SPECIAL_SCHEMES = [
'ftp' => 21,
'file' => null,
'http' => 80,
'https' => 443,
'ws' => 80,
'wss' => 443,
];
protected $scheme = null;
protected $user = "";
protected $pass = "";
protected $host = null;
protected $port = null;
protected $path = null;
protected $query = null;
protected $fragment = null;
public static function fromUri(UriInterface $uri): self {
return ($uri instanceof self) ? $uri : new self((string) $uri);
}
public static function fromString(string $url, string $baseUrl = null): ?self {
try {
return new static($url, $baseUrl);
} catch (\InvalidArgumentException $e) {
return null;
}
}
public function __construct(string $url, string $baseUrl = null) {
$url = str_replace(["\t", "\n", "\r"], "", trim($url, self::WHITESPACE_CHARS));
if (preg_match(self::URI_PATTERN, $url, $match)) {
[$url, $scheme, $authority, $path, $query, $fragment] = array_pad($match, 6, "");
foreach (["scheme", "path", "query", "fragment"] as $part) {
if (strlen($$part)) {
if ($part === "query" || $part === "fragment") {
$$part = substr($$part, 1);
}
$this->set($part, $$part);
}
}
if (strlen($authority)) {
$authority = substr($authority, 2);
if (($cleft = strrpos($authority, "@")) !== false) {
if (preg_match(self::USER_PATTERN, substr($authority, 0, $cleft), $match)) {
$this->set("user", $match[1]);
$this->set("pass", $match[2] ?? "");
}
if (preg_match(self::HOST_PATTERN, substr($authority, $cleft + 1), $match)) {
$this->set("host", $match[1]);
$this->set("port", $match[2] ?? "");
}
} elseif (preg_match(self::HOST_PATTERN, $authority, $match)) {
$this->set("host", $match[1]);
$this->set("port", $match[2] ?? "");
}
}
if ((!$this->scheme || ($this->host === null && array_key_exists($this->scheme, self::SPECIAL_SCHEMES))) && strlen($baseUrl ?? "")) {
$this->resolve(new static($baseUrl));
}
foreach (["scheme", "path"] as $part) {
$this->$part = $this->$part ?? "";
}
} else {
throw new \InvalidArgumentException("String is not a valid URI");
}
}
public function getAuthority() {
$host = $this->getHost();
if (strlen($host) > 0) {
$userInfo = $this->getUserInfo();
$port = $this->getPort();
return (strlen($userInfo) ? $userInfo."@" : "").$host.(!is_null($port) ? ":".$port : "");
}
return "";
}
public function getFragment() {
return $this->fragment ?? "";
}
public function getHost() {
return $this->host ?? "";
}
public function getPath() {
return $this->path ?? "";
}
public function getPort() {
return $this->port;
}
public function getQuery() {
return $this->query ?? "";
}
public function getScheme() {
return $this->scheme ?? "";
}
public function getUserInfo() {
if (strlen($this->user ?? "")) {
return $this->user.(strlen($this->pass ?? "") ? ":".$this->pass : "");
}
return "";
}
public function withFragment($fragment) {
$out = clone $this;
if (!strlen((string) $fragment)) {
$out->fragment = null;
} else {
$out->set("fragment", $fragment);
}
return $out;
}
public function withHost($host) {
if ($host === "") {
$host = null;
}
$out = clone $this;
$out->set("host", $host);
return $out;
}
public function withPath($path) {
$out = clone $this;
$out->set("path", $path);
return $out;
}
public function withPort($port) {
$out = clone $this;
$out->set("port", $port);
return $out;
}
public function withQuery($query) {
$out = clone $this;
if (!strlen((string) $query)) {
$out->query = null;
} else {
$out->set("query", $query);
}
return $out;
}
public function withScheme($scheme) {
$out = clone $this;
$out->set("scheme", $scheme);
return $out;
}
public function withUserInfo($user, $password = null) {
$out = clone $this;
$out->set("user", $user);
$out->set("pass", $password);
return $out;
}
public function __toString() {
$out = "";
$out .= strlen($this->scheme) ? $this->scheme.":" : "";
if (is_null($this->host)) {
$out .= $this->path;
} else {
$auth = $this->host;
$auth .= (strlen($auth) && !is_null($this->port)) ? ":".$this->port : "";
$user = $this->user.(strlen($this->pass) ? ":".$this->pass : "");
$auth = (strlen($auth) && strlen($user)) ? "$user@$auth" : $auth;
$out .= "//";
$out .= $auth;
$out .= ($this->path[0] ?? "") !== "/" && strlen($auth) ? "/" : "";
$out .= preg_replace("<^/{2,}/>", "/", $this->path);
}
$out .= is_string($this->query) ? "?".$this->query : "";
$out .= is_string($this->fragment) ? "#".$this->fragment : "";
return $out;
}
public function __get(string $name) {
return $this->$name;
}
protected function set(string $name, $value): void {
switch ($name) {
case "host":
$this->host = $this->normalizeHost($value);
break;
case "port":
if (!strlen((string) $value)) {
$this->port = null;
} elseif (preg_match(self::PORT_PATTERN, (string) $value) && (int) $value <= 0xFFFF) {
$value = (int) $value;
if (array_key_exists($this->scheme, self::SPECIAL_SCHEMES) && $value === self::SPECIAL_SCHEMES[$this->scheme]) {
$this->port = null;
} else {
$this->port = $value;
}
} else {
throw new \InvalidArgumentException("Port must be an integer between 0 and 65535, or null");
}
break;
case "scheme":
if (preg_match(self::SCHEME_PATTERN, $value)) {
$this->scheme = strtolower($value);
} else {
throw new \InvalidArgumentException("Invalid scheme specified");
}
break;
default:
$this->$name = $this->normalizeEncoding((string) $value, $name);
}
}
protected function resolve(self $base): void {
[$scheme, $host, $user, $pass, $port, $path, $query, $fragment] = [$base->scheme, $base->host, $base->user, $base->pass, $base->port, $base->path, $base->query, $base->fragment];
if (strlen($scheme) && is_null($host)) {
throw new \InvalidArgumentException("URL base must not be a Uniform Resource Name");
}
$this->scheme = $this->scheme ?? $scheme;
if (is_null($this->host)) {
$this->host = $host;
$this->user = $user;
$this->pass = $pass;
$this->port = $port;
if (is_null($this->path)) {
$this->path = $path;
if (is_null($this->query)) {
$this->query = $query;
if (is_null($this->fragment)) {
$this->fragment = $fragment;
}
}
} elseif (strlen($path)) {
if ($this->path[0] !== "/") {
if ($path[-1] === "/") {
$this->path = $path.$this->path;
} else {
$len = strrpos($path, "/");
$len = ($len === false) ? 0 : $len + 1;
$this->path = substr($path, 0, $len).$this->path;
}
}
}
}
}
protected function normalizeEncoding(string $data, string $part = null): string {
$pos = 0;
$end = strlen($data);
$out = "";
$esc = self::ESCAPE_CHARS[$part] ?? [];
// process each character in sequence
while ($pos < $end) {
$c = $data[$pos];
if ($c === "%") {
// the % character signals an encoded character...
$d = substr($data, $pos + 1, 2);
if (!preg_match("/^[0-9a-fA-F]{2}$/", $d)) {
// unless there are fewer than two characters left in the string or the two characters are not hex digits
$d = ord($c);
} else {
$d = hexdec($d);
$pos += 2;
}
} else {
$d = ord($c);
}
$dc = chr($d);
if ($d < 0x21 || $d > 0x7E || $d == 0x25) {
// these characters are always encoded
$out .= "%".strtoupper(dechex($d));
} elseif (preg_match("/[a-zA-Z0-9\._~-]/", $dc)) {
// these characters are never encoded
$out .= $dc;
} else {
// these characters are passed through as-is...
if ($c === "%") {
$out .= "%".strtoupper(dechex($d));
} else {
// unless the part we're processing has delimiters which must be escaped
if (in_array($dc, $esc)) {
$out .= "%".strtoupper(dechex($d));
} else {
$out .= $c;
}
}
}
$pos++;
}
return $out;
}
/** Normalizes a hostname per IDNA:2008 */
protected function normalizeHost(?string $host): ?string {
if (!is_null($host) && strlen($host)) {
if (preg_match(self::IPV6_PATTERN, $host)) {
// normalize IPv6 addresses
$addr = @inet_pton(substr($host, 1, strlen($host) - 2));
if ($addr !== false) {
return "[".inet_ntop($addr)."]";
}
}
$idn = idn_to_ascii($host, \IDNA_NONTRANSITIONAL_TO_ASCII | \IDNA_CHECK_BIDI | \IDNA_CHECK_CONTEXTJ, \INTL_IDNA_VARIANT_UTS46);
if ($idn === false) {
throw new \InvalidArgumentException("Invalid host in URL");
} elseif (preg_match(self::FORBIDDEN_HOST_PATTERN, $idn)) {
throw new \InvalidArgumentException("Invalid host in URL");
}
$host = idn_to_utf8($idn, \IDNA_NONTRANSITIONAL_TO_UNICODE | \IDNA_USE_STD3_RULES, \INTL_IDNA_VARIANT_UTS46);
if ($host === false) {
throw new \InvalidArgumentException("Invalid host in URL");
}
}
return $host;
}
}