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Arsse/lib/REST.php
2024-12-15 16:31:57 -05:00

308 lines
14 KiB
PHP

<?php
/** @license MIT
* Copyright 2017 J. King, Dustin Wilson et al.
* See LICENSE and AUTHORS files for details */
declare(strict_types=1);
namespace JKingWeb\Arsse;
use JKingWeb\Arsse\Misc\URL;
use JKingWeb\Arsse\Misc\HTTP;
use Psr\Http\Message\RequestInterface;
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Message\ResponseInterface;
use GuzzleHttp\Psr7\ServerRequest;
class REST {
public const API_LIST = [
'ncn' => [ // Nextcloud News version enumerator
'match' => '/index.php/apps/news/api',
'strip' => '/index.php/apps/news/api',
'class' => REST\NextcloudNews\Versions::class,
],
'ncn_v1-2' => [ // Nextcloud News v1-2 https://github.com/nextcloud/news/blob/master/docs/externalapi/Legacy.md
'match' => '/index.php/apps/news/api/v1-2/',
'strip' => '/index.php/apps/news/api/v1-2',
'class' => REST\NextcloudNews\V1_2::class,
],
'ttrss_api' => [ // Tiny Tiny RSS https://git.tt-rss.org/git/tt-rss/wiki/ApiReference
'match' => '/tt-rss/api',
'strip' => '/tt-rss/api',
'class' => REST\TinyTinyRSS\API::class,
],
'ttrss_icon' => [ // Tiny Tiny RSS feed icons
'match' => '/tt-rss/feed-icons/',
'strip' => '/tt-rss/feed-icons/',
'class' => REST\TinyTinyRSS\Icon::class,
],
'fever' => [ // Fever https://web.archive.org/web/20161217042229/https://feedafever.com/api
'match' => '/fever/',
'strip' => '/fever/',
'class' => REST\Fever\API::class,
],
'miniflux' => [ // Miniflux https://miniflux.app/docs/api.html
'match' => '/v1/',
'strip' => '/v1',
'class' => REST\Miniflux\V1::class,
],
'miniflux-version' => [ // Miniflux version report
'match' => '/version',
'strip' => '',
'class' => REST\Miniflux\Status::class,
],
'miniflux-healthcheck' => [ // Miniflux health check
'match' => '/healthcheck',
'strip' => '',
'class' => REST\Miniflux\Status::class,
],
// Other candidates:
// Microsub https://indieweb.org/Microsub
// Google Reader http://feedhq.readthedocs.io/en/latest/api/index.html
// Feedbin v2 https://github.com/feedbin/feedbin-api
// CommaFeed https://www.commafeed.com/api/
// Selfoss https://github.com/SSilence/selfoss/wiki/Restful-API-for-Apps-or-any-other-external-access
// NewsBlur http://www.newsblur.com/api
// Unclear if clients exist:
// Nextcloud News v2 https://github.com/nextcloud/news/blob/master/docs/externalapi/External-Api.md
// BirdReader https://github.com/glynnbird/birdreader/blob/master/API.md
// Feedbin v1 https://github.com/feedbin/feedbin-api/commit/86da10aac5f1a57531a6e17b08744e5f9e7db8a9
// Proprietary (centralized) entities:
// Feedly https://developer.feedly.com/
];
protected const DEFAULT_PORTS = [
'http' => 80,
'https' => 443,
];
protected $apis = [];
public function __construct(?array $apis = null) {
$this->apis = $apis ?? self::API_LIST;
}
public function dispatch(?ServerRequestInterface $req = null): ResponseInterface {
try {
// ensure the require extensions are loaded
Arsse::checkExtensions(...Arsse::REQUIRED_EXTENSIONS);
// create a request object if not provided
$req = $req ?? ServerRequest::fromGlobals();
// find the API to handle
[, $target, $class] = $this->apiMatch($req->getRequestTarget(), $this->apis);
// authenticate the request pre-emptively
$req = $this->authenticateRequest($req);
// modify the request to have an uppercase method and a stripped target
$req = $req->withMethod(strtoupper($req->getMethod()))->withRequestTarget($target);
// fetch the correct handler
$drv = Arsse::$obj->get($class);
// generate a response
if ($req->getMethod() === "HEAD") {
// if the request is a HEAD request, we act exactly as if it were a GET request, and simply remove the response body later
$res = $drv->dispatch($req->withMethod("GET"));
} else {
$res = $drv->dispatch($req);
}
} catch (REST\Exception501 $e) {
$res = HTTP::respEmpty(501);
}
// modify the response so that it has all the required metadata
return $this->normalizeResponse($res, $req);
}
public function apiMatch(string $url): array {
$map = $this->apis;
// sort the API list so the longest URL prefixes come first
uasort($map, function($a, $b) {
return (strlen($a['match']) <=> strlen($b['match'])) * -1;
});
// normalize the target URL
$url = URL::normalize($url);
// find a match
foreach ($map as $id => $api) {
// first try a simple substring match
if (strpos($url, $api['match']) === 0) {
// if it matches, perform a more rigorous match and then strip off any defined prefix
$pattern = "<^".preg_quote($api['match'])."([/\?#]|$)>D";
if ($url === $api['match'] || in_array(substr($api['match'], -1, 1), ["/", "?", "#"]) || preg_match($pattern, $url)) {
$target = substr($url, strlen($api['strip']));
} else {
// if the match fails we are not able to handle the request
throw new REST\Exception501();
}
// return the API name, stripped URL, and API class name
return [$id, $target, $api['class']];
}
}
// or throw an exception otherwise
throw new REST\Exception501();
}
public function authenticateRequest(ServerRequestInterface $req): ServerRequestInterface {
$user = "";
$password = "";
$env = $req->getServerParams();
if (isset($env['PHP_AUTH_USER'])) {
$user = $env['PHP_AUTH_USER'];
if (isset($env['PHP_AUTH_PW'])) {
$password = $env['PHP_AUTH_PW'];
}
} elseif (isset($env['REMOTE_USER'])) {
$user = $env['REMOTE_USER'];
}
if (strlen($user)) {
if (Arsse::$user->auth((string) $user, (string) $password)) {
$req = $req->withAttribute("authenticated", true);
$req = $req->withAttribute("authenticatedUser", $user);
} else {
$req = $req->withAttribute("authenticationFailed", true);
}
}
return $req;
}
public function challenge(ResponseInterface $res, ?string $realm = null): ResponseInterface {
$realm = $realm ?? Arsse::$conf->httpRealm;
return $res->withAddedHeader("WWW-Authenticate", 'Basic realm="'.$realm.'", charset="UTF-8"');
}
public function normalizeResponse(ResponseInterface $res, ?RequestInterface $req = null): ResponseInterface {
// if the response code is 401, issue an HTTP authentication challenge
if ($res->getStatusCode() == 401) {
$res = $this->challenge($res);
}
// set or clear the Content-Length header field
$body = $res->getBody();
$bodySize = $body->getSize();
if ($bodySize || $res->getStatusCode() == 200) {
// if there is a message body or the response is 200, make sure Content-Length is included
$res = $res->withHeader("Content-Length", (string) $bodySize);
} else {
// for empty responses of other statuses, omit it
$res = $res->withoutHeader("Content-Length");
}
// if the response is to a HEAD request, the body should be omitted
if ($req && $req->getMethod() === "HEAD") {
$res = HTTP::respEmpty($res->getStatusCode(), $res->getHeaders());
}
// if an Allow header field is present, normalize it
if ($res->hasHeader("Allow")) {
$methods = preg_split("<\s*,\s*>", strtoupper($res->getHeaderLine("Allow")));
// if GET is allowed, HEAD should be allowed as well
if (in_array("GET", $methods) && !in_array("HEAD", $methods)) {
$methods[] = "HEAD";
}
// OPTIONS requests are always allowed by our handlers
if (!in_array("OPTIONS", $methods)) {
$methods[] = "OPTIONS";
}
$res = $res->withHeader("Allow", implode(", ", $methods));
}
// add CORS header fields if the request origin is specified and allowed
if ($req && $this->corsNegotiate($req)) {
$res = $this->corsApply($res, $req);
}
return $res;
}
public function corsApply(ResponseInterface $res, ?RequestInterface $req = null): ResponseInterface {
if ($req && $req->getMethod() === "OPTIONS") {
if ($res->hasHeader("Allow")) {
$res = $res->withHeader("Access-Control-Allow-Methods", $res->getHeaderLine("Allow"));
}
if ($req->hasHeader("Access-Control-Request-Headers")) {
$res = $res->withHeader("Access-Control-Allow-Headers", $req->getHeaderLine("Access-Control-Request-Headers"));
}
$res = $res->withHeader("Access-Control-Max-Age", (string) (60 * 60 * 24)); // one day
}
$res = $res->withHeader("Access-Control-Allow-Origin", $req->getHeaderLine("Origin"));
$res = $res->withHeader("Access-Control-Allow-Credentials", "true");
return $res->withAddedHeader("Vary", "Origin");
}
public function corsNegotiate(RequestInterface $req, ?string $allowed = null, ?string $denied = null): bool {
$allowed = trim($allowed ?? Arsse::$conf->httpOriginsAllowed);
$denied = trim($denied ?? Arsse::$conf->httpOriginsDenied);
// continue if at least one origin is allowed
if ($allowed) {
// continue if the request has exactly one Origin header
$origin = $req->getHeader("Origin");
if (sizeof($origin) == 1) {
// continue if the origin is syntactically valid
$origin = $this->corsNormalizeOrigin($origin[0]);
if ($origin) {
// the special "null" origin should not be matched by the wildcard origin
$null = ($origin === "null");
// pad all strings for simpler comparison
$allowed = " ".$allowed." ";
$denied = " ".$denied." ";
$origin = " ".$origin." ";
$any = " * ";
if (strpos($denied, $origin) !== false) {
// first check the denied list for the origin
return false;
} elseif (strpos($allowed, $origin) !== false) {
// next check the allowed list for the origin
return true;
} elseif (!$null && strpos($denied, $any) !== false) {
// next check the denied list for the wildcard origin
return false;
} elseif (!$null && strpos($allowed, $any) !== false) {
// finally check the allowed list for the wildcard origin
return true;
}
}
}
}
return false;
}
public function corsNormalizeOrigin(string $origin, ?array $ports = null): string {
$origin = trim($origin);
if ($origin === "null") {
// if the origin is the special value "null", use it
return "null";
}
if (preg_match("<^([^:]+)://(\[[^\]]+\]|[^\[\]:/\?#@]+)((?::.*)?)$>Di", $origin, $match)) {
// if the origin sort-of matches the syntax in a general sense, continue
$scheme = $match[1];
$host = $match[2];
$port = $match[3];
// decode and normalize the scheme and port (the port may be blank)
$scheme = strtolower(rawurldecode($scheme));
$port = rawurldecode($port);
if (!preg_match("<^(?::[0-9]+)?$>D", $port) || !preg_match("<^[a-z](?:[a-z0-9\+\-\.])*$>D", $scheme)) {
// if the normalized port contains anything but numbers, or the scheme does not follow the generic URL syntax, the origin is invalid
return "";
}
if ($host[0] === "[") {
// if the host appears to be an IPv6 address, validate it
$host = rawurldecode(substr($host, 1, strlen($host) - 2));
if (!filter_var($host, \FILTER_VALIDATE_IP, \FILTER_FLAG_IPV6)) {
return "";
} else {
$host = "[".inet_ntop(inet_pton($host))."]";
}
} else {
// if the host is a domain name or IP address, split it along dots and just perform URL decoding
$host = explode(".", $host);
$host = array_map(function($segment) {
return str_replace(".", "%2E", rawurlencode(strtolower(rawurldecode($segment))));
}, $host);
$host = implode(".", $host);
}
// suppress default ports
if (strlen($port)) {
$port = (int) substr($port, 1);
$list = array_merge($ports ?? [], self::DEFAULT_PORTS);
if (isset($list[$scheme]) && $port == $list[$scheme]) {
$port = "";
} else {
$port = ":".$port;
}
}
// return the reconstructed result
return $scheme."://".$host.$port;
} else {
return "";
}
}
}