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Client.php
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Client.php
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<?php
namespace WordPress\AsyncHttp;
use WordPress\AsyncHttp\StreamWrapper\ChunkedEncodingWrapper;
use WordPress\AsyncHttp\StreamWrapper\EventLoopWrapper;
use WordPress\AsyncHttp\StreamWrapper\InflateStreamWrapper;
/**
* An asynchronous HTTP client library.
*
* This class makes non-blocking HTTP requests using just native PHP streams.
* It uses an event-driven architecture.
*
* ### Key Features
*
* - **Streaming support:** Enables efficient handling of large response bodies.
* - **Progress monitoring:** Track the progress of requests and responses.
* - **Concurrency limits:** Control the number of simultaneous connections.
* - **PHP 7.2+ support and no dependencies:** Works on vanilla PHP without external libraries.
*
* ### Usage Example
*
* ```php
* $requests = [
* new Request("[https://wordpress.org/latest.zip](https://wordpress.org/latest.zip)"),
* new Request("[https://github.com/raw/wpaccessibility/a11y-theme-unit-test/master/a11y-theme-unit-test-data.xml](https://github.com/raw/wpaccessibility/a11y-theme-unit-test/master/a11y-theme-unit-test-data.xml)"),
* ];
*
* $client = new Client();
* $client->enqueue($requests);
*
* while ($client->await_next_event()) {
* $event = $client->get_event();
* $request = $client->get_request();
*
* if ($event === Client::EVENT_BODY_CHUNK_AVAILABLE) {
* $chunk = $client->get_response_body_chunk();
* // Process the chunk...
* }
* // Handle other events...
* }
* ```
*
* @since Next Release
* @package WordPress
* @subpackage Async_HTTP
*/
class Client {
/**
* The maximum number of concurrent connections allowed.
*
* This is as a safeguard against:
* * Spreading our network bandwidth too thin and not making any real progress on any
* request.
* * Overwhelming the server with too many requests.
*
* @var int
*/
private $concurrency;
/**
* The maximum number of redirects to follow for a single request.
*
* This prevents infinite redirect loops and provides a degree of control over the client's behavior.
* Setting it too high might lead to unexpected navigation paths.
*
* @var int
*/
private $max_redirects = 3;
/**
* All the HTTP requests ever enqueued with this Client.
*
* Each Request may have a different state, and this Client will manage them
* asynchronously, moving them through the various states as the network
* operations progress.
*
* @since Next Release
* @var Request[]
*/
private $requests;
/**
* Network connection details managed privately by this Client.
*
* Each Request has a corresponding Connection object that contains
* the network socket, response buffer, and other connection-specific details.
*
* These are internal, will change, and should not be exposed to the outside world.
*
* @var array
*/
private $connections = array();
private $events = array();
private $event;
private $request;
private $response_body_chunk;
public function __construct( $options = [] ) {
$this->concurrency = $options['concurrency'] ?? 10;
$this->max_redirects = $options['max_redirects'] ?? 3;
$this->requests = [];
}
/**
* Enqueues one or multiple HTTP requests for asynchronous processing.
* It does not open the network sockets, only adds the Request objects to
* an internal queue. Network transmission is delayed until one of the returned
* streams is read from.
*
* @param Request|Request[] $requests The HTTP request(s) to enqueue. Can be a single request or an array of requests.
*/
public function enqueue( $requests ) {
if ( ! is_array( $requests ) ) {
$requests = [ $requests ];
}
foreach ( $requests as $request ) {
$this->requests[] = $request;
$this->events[ $request->id ] = [];
$this->connections[ $request->id ] = new Connection( $request );
}
}
/**
* Returns the next event related to any of the HTTP
* requests enqueued in this client.
*
* ## Events
*
* The returned event is a ClientEvent with $event->name
* being one of the following:
*
* * `Client::EVENT_GOT_HEADERS`
* * `Client::EVENT_BODY_CHUNK_AVAILABLE`
* * `Client::EVENT_REDIRECT`
* * `Client::EVENT_FAILED`
* * `Client::EVENT_FINISHED`
*
* See the ClientEvent class for details on each event.
*
* Once an event is consumed, it is removed from the
* event queue and will not be returned again.
*
* When there are no events available, this function
* blocks and waits for the next one. If all requests
* have already finished, and we are not waiting for
* any more events, it returns false.
*
* ## Filtering
*
* The $query parameter can be used to filter the events
* that are returned. It can contain the following keys:
*
* * `request_id` – The ID of the request to consider.
*
* For example, to only consider the next `EVENT_GOT_HEADERS`
* event for a specific request, you can use:
*
* ```php
* $request = new Request( "https://w.org" );
*
* $client = new AsyncHttpClient();
* $client->enqueue( $request );
* $event = $client->await_next_event( [
* 'request_id' => $request->id,
* ] );
* ```
*
* Importantly, filtering does not consume unrelated events.
* You can await all the events for a request #2, and
* then await the next event for request #1 even if the
* request #1 has finished before you started awaiting
* events for request #2.
*
* @param $query
*
* @return bool
*/
public function await_next_event( $query = [] ) {
$ordered_events = [
Client::EVENT_GOT_HEADERS,
Client::EVENT_BODY_CHUNK_AVAILABLE,
Client::EVENT_REDIRECT,
Client::EVENT_FAILED,
Client::EVENT_FINISHED,
];
$this->event = null;
$this->request = null;
$this->response_body_chunk = null;
do {
if ( empty( $query['requests'] ) ) {
$events = array_keys( $this->events );
} else {
$events = [];
foreach ( $query['requests'] as $query_request ) {
$events[] = $query_request->id;
while ( $query_request->redirected_to ) {
$query_request = $query_request->redirected_to;
$events[] = $query_request->id;
}
}
}
foreach ( $events as $request_id ) {
foreach ( $ordered_events as $considered_event ) {
$needs_emitting = $this->events[ $request_id ][ $considered_event ] ?? false;
if ( ! $needs_emitting ) {
continue;
}
$this->events[ $request_id ][ $considered_event ] = false;
$this->event = $considered_event;
$this->request = $this->get_request_by_id( $request_id );
if ( $this->event === Client::EVENT_BODY_CHUNK_AVAILABLE ) {
$this->response_body_chunk = $this->next_response_body_bytes();
}
return true;
}
}
} while ( $this->event_loop_tick() );
return false;
}
/**
* Returns the next event found by await_next_event().
*
* @return string|bool The next event, or false if no event is set.
*/
public function get_event() {
if ( null === $this->event ) {
return false;
}
return $this->event;
}
/**
* Returns the request associated with the last event found
* by await_next_event().
*
* @return Request
*/
public function get_request() {
if ( null === $this->request ) {
return false;
}
return $this->request;
}
/**
* Returns the response body chunk associated with the EVENT_BODY_CHUNK_AVAILABLE
* event found by await_next_event().
*
* @return Request
*/
public function get_response_body_chunk() {
if ( null === $this->response_body_chunk ) {
return false;
}
return $this->response_body_chunk;
}
/**
* Asynchronously moves the enqueued Request objects through the
* various states of the HTTP request-response lifecycle.
*
* @return bool Whether any active requests were processed.
*/
private function event_loop_tick() {
if ( count( $this->get_active_requests() ) === 0 ) {
return false;
}
$this->open_nonblocking_http_sockets(
$this->get_active_requests( Request::STATE_ENQUEUED )
);
$this->enable_crypto(
$this->get_active_requests( Request::STATE_WILL_ENABLE_CRYPTO )
);
$this->send_request_headers(
$this->get_active_requests( Request::STATE_WILL_SEND_HEADERS )
);
$this->send_request_body(
$this->get_active_requests( Request::STATE_WILL_SEND_BODY )
);
$this->receive_response_headers(
$this->get_active_requests( Request::STATE_RECEIVING_HEADERS )
);
$this->receive_response_body(
$this->get_active_requests( Request::STATE_RECEIVING_BODY )
);
$this->handle_redirects(
$this->get_active_requests( Request::STATE_RECEIVED )
);
return true;
}
/**
* Consumes $length bytes received in response to a given request.
*
* @return string
*/
private function next_response_body_bytes() {
if ( null === $this->request ) {
return false;
}
$request = $this->request;
$connection = $this->connections[ $request->id ];
if (
$request->state === Request::STATE_RECEIVING_BODY ||
$request->state === Request::STATE_FINISHED
) {
return $connection->consume_buffer();
}
$end_of_data = $request->state === Request::STATE_FINISHED && (
! is_resource( $this->connections[ $request->id ]->http_socket ) ||
feof( $this->connections[ $request->id ]->decoded_response_stream )
);
if ( $end_of_data ) {
return false;
}
return '';
}
private function mark_finished( Request $request ) {
$request->state = Request::STATE_FINISHED;
$this->events[ $request->id ][ Client::EVENT_FINISHED ] = true;
$this->close_connection( $request );
}
private function set_error( Request $request, $error ) {
$request->error = $error;
$request->state = Request::STATE_FAILED;
$this->events[ $request->id ][ Client::EVENT_FAILED ] = true;
$this->close_connection( $request );
}
private function close_connection( Request $request ) {
$socket = $this->connections[ $request->id ]->http_socket;
if ( $socket && is_resource( $socket ) ) {
// Close the TCP socket
@fclose( $socket );
// No need to close all the dependent stream wrappers – they are
// invalidated when the root resource is closed.
}
}
public function get_active_requests( $states = null ) {
$processed_requests = $this->get_requests( [
Request::STATE_WILL_ENABLE_CRYPTO,
Request::STATE_WILL_SEND_HEADERS,
Request::STATE_WILL_SEND_BODY,
Request::STATE_SENT,
Request::STATE_RECEIVING_HEADERS,
Request::STATE_RECEIVING_BODY,
Request::STATE_RECEIVED,
] );
$available_slots = $this->concurrency - count( $processed_requests );
$enqueued_requests = $this->get_requests( Request::STATE_ENQUEUED );
for ( $i = 0; $i < $available_slots; $i ++ ) {
if ( ! isset( $enqueued_requests[ $i ] ) ) {
break;
}
$processed_requests[] = $enqueued_requests[ $i ];
}
if ( $states !== null ) {
$processed_requests = static::filter_requests( $processed_requests, $states );
}
return $processed_requests;
}
public function get_failed_requests() {
return $this->get_requests( Request::STATE_FAILED );
}
private function get_requests( $states ) {
if ( ! is_array( $states ) ) {
$states = [ $states ];
}
return static::filter_requests( $this->requests, $states );
}
private function get_request_by_id( $request_id ) {
foreach ( $this->requests as $request ) {
if ( $request->id === $request_id ) {
return $request;
}
}
}
/**
* Handle transfer encodings.
*
* @param Request $request
*
* @return false|resource
*/
private function decode_and_monitor_response_body_stream( Request $request ) {
$wrapped_stream = $this->connections[ $request->id ]->http_socket;
$transfer_encodings = array();
$transfer_encoding = $request->response->get_header( 'transfer-encoding' );
if ( $transfer_encoding ) {
$transfer_encodings = array_map( 'trim', explode( ',', $transfer_encoding ) );
}
$content_encoding = $request->response->get_header( 'content-encoding' );
if ( $content_encoding && ! in_array( $content_encoding, $transfer_encodings ) ) {
$transfer_encodings[] = $content_encoding;
}
foreach ( $transfer_encodings as $transfer_encoding ) {
switch ( $transfer_encoding ) {
case 'chunked':
/**
* Wrap the stream in a chunked encoding decoder.
* There was an attempt to use stream filters, but unfortunately
* they are incompatible with stream_select().
*/
$wrapped_stream = ChunkedEncodingWrapper::wrap( $wrapped_stream );
break;
case 'gzip':
case 'deflate':
$wrapped_stream = InflateStreamWrapper::wrap(
$wrapped_stream,
$transfer_encoding === 'gzip' ? ZLIB_ENCODING_GZIP : ZLIB_ENCODING_RAW
);
break;
case 'identity':
// No-op
break;
default:
$this->set_error( $request,
new HttpError( 'Unsupported transfer encoding received from the server: ' . $transfer_encoding ) );
break;
}
}
return $wrapped_stream;
}
/**
* Sends HTTP requests using streams.
*
* Enables crypto on the $requests HTTP socksts and sends the request body asynchronously.
*
* @param Request[] $requests An array of HTTP requests.
*/
private function enable_crypto( array $requests ) {
foreach ( $this->stream_select( $requests, static::STREAM_SELECT_WRITE ) as $request ) {
$enabled_crypto = stream_socket_enable_crypto(
$this->connections[ $request->id ]->http_socket,
true,
STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT
);
if ( false === $enabled_crypto ) {
$this->set_error( $request, new HttpError( 'Failed to enable crypto: ' . error_get_last()['message'] ) );
continue;
} elseif ( 0 === $enabled_crypto ) {
// The SSL handshake isn't finished yet, let's skip it
// for now and try again on the next event loop pass.
continue;
}
// SSL connection established, let's send the headers.
$request->state = Request::STATE_WILL_SEND_HEADERS;
}
}
/**
* Sends HTTP request headers.
*
* @param Request[] $requests An array of HTTP requests.
*/
private function send_request_headers( array $requests ) {
foreach ( $this->stream_select( $requests, static::STREAM_SELECT_WRITE ) as $request ) {
$header_bytes = static::prepare_request_headers( $request );
if ( false === @fwrite( $this->connections[ $request->id ]->http_socket, $header_bytes ) ) {
$this->set_error( $request, new HttpError( 'Failed to write request bytes – ' . error_get_last()['message'] ) );
continue;
}
if ( $request->upload_body_stream ) {
$request->state = Request::STATE_WILL_SEND_BODY;
} else {
$request->state = Request::STATE_RECEIVING_HEADERS;
}
}
}
/**
* Sends HTTP request body.
*
* @param Request[] $requests An array of HTTP requests.
*/
private function send_request_body( array $requests ) {
foreach ( $this->stream_select( $requests, self::STREAM_SELECT_WRITE ) as $request ) {
$chunk = fread( $request->upload_body_stream, 8192 );
if ( false === $chunk ) {
$this->set_error( $request, new HttpError( 'Failed to read from the request body stream' ) );
continue;
}
if ( false === fwrite( $this->connections[ $request->id ]->http_socket, $chunk ) ) {
$this->set_error( $request, new HttpError( 'Failed to write request bytes.' ) );
continue;
}
if ( '' === $chunk || feof( $request->upload_body_stream ) ) {
fclose( $request->upload_body_stream );
$request->upload_body_stream = null;
$request->state = Request::STATE_RECEIVING_HEADERS;
}
}
}
/**
* Reads the next received portion of HTTP response headers for multiple requests.
*
* @param array $requests An array of requests.
*/
private function receive_response_headers( $requests ) {
foreach ( $this->stream_select( $requests, static::STREAM_SELECT_READ ) as $request ) {
if ( ! $request->response ) {
$request->response = new Response( $request );
}
$connection = $this->connections[ $request->id ];
$response = $request->response;
while ( true ) {
// @TODO: Use a larger chunk size here and then scan for \r\n\r\n.
// 1 seems slow and overly conservative.
$header_byte = fread( $this->connections[ $request->id ]->http_socket, 1 );
if ( false === $header_byte || '' === $header_byte ) {
break;
}
$connection->response_buffer .= $header_byte;
$buffer_size = strlen( $connection->response_buffer );
if (
$buffer_size < 4 ||
$connection->response_buffer[ $buffer_size - 4 ] !== "\r" ||
$connection->response_buffer[ $buffer_size - 3 ] !== "\n" ||
$connection->response_buffer[ $buffer_size - 2 ] !== "\r" ||
$connection->response_buffer[ $buffer_size - 1 ] !== "\n"
) {
continue;
}
$parsed = static::parse_http_headers( $connection->response_buffer );
$connection->response_buffer = '';
$response->headers = $parsed['headers'];
$response->status_code = $parsed['status']['code'];
$response->status_message = $parsed['status']['message'];
$response->protocol = $parsed['status']['protocol'];
$total = $request->response->get_header( 'content-length' ) ?: null;
if ( $total !== null ) {
$response->total_bytes = (int) $total;
}
// If we're being redirected, we don't need to wait for the body.
if ( $response->status_code >= 300 && $response->status_code < 400 ) {
$request->state = Request::STATE_RECEIVED;
break;
}
$request->state = Request::STATE_RECEIVING_BODY;
$this->events[ $request->id ][ Client::EVENT_GOT_HEADERS ] = true;
break;
}
}
}
/**
* Reads the next received portion of HTTP response headers for multiple requests.
*
* @param array $requests An array of requests.
*/
private function receive_response_body( $requests ) {
// @TODO: Assume body is fully received when either
// * Content-Length is reached
// * The last chunk in Transfer-Encoding: chunked is received
// * The connection is closed
foreach ( $this->stream_select( $requests, static::STREAM_SELECT_READ ) as $request ) {
if ( ! $this->connections[ $request->id ]->decoded_response_stream ) {
$this->connections[ $request->id ]->decoded_response_stream = $this->decode_and_monitor_response_body_stream( $request );
}
while ( true ) {
if ( feof( $this->connections[ $request->id ]->decoded_response_stream ) ) {
$request->state = Request::STATE_RECEIVED;
break;
}
$body_bytes = fread( $this->connections[ $request->id ]->decoded_response_stream, 8096 );
if ( false === $body_bytes || '' === $body_bytes ) {
break;
}
$request->response->received_bytes += strlen( $body_bytes );
$this->connections[ $request->id ]->response_buffer .= $body_bytes;
$this->events[ $request->id ][ Client::EVENT_BODY_CHUNK_AVAILABLE ] = true;
}
}
}
/**
* @param array $requests An array of requests.
*/
private function handle_redirects( $requests ) {
foreach ( $requests as $request ) {
$response = $request->response;
$code = $response->status_code;
$this->mark_finished( $request );
if ( ! ( $code >= 300 && $code < 400 ) ) {
continue;
}
$location = $response->get_header( 'location' );
if ( $location === null ) {
continue;
}
$redirects_so_far = 0;
$cause = $request;
while ( $cause->redirected_from ) {
++ $redirects_so_far;
$cause = $cause->redirected_from;
}
if ( $redirects_so_far >= $this->max_redirects ) {
$this->set_error( $request, new HttpError( 'Too many redirects' ) );
continue;
}
$redirect_url = $location;
if ( strpos( $redirect_url, 'http://' ) !== 0 && strpos( $redirect_url, 'https://' ) !== 0 ) {
$current_url_parts = parse_url( $request->url );
$redirect_url = $current_url_parts['scheme'] . '://' . $current_url_parts['host'];
if ( $current_url_parts['port'] ) {
$redirect_url .= ':' . $current_url_parts['port'];
}
if ( strlen( $location ) === 0 || $location[0] !== '/' ) {
$redirect_url .= '/';
}
$redirect_url .= $location;
}
// @TODO: Use a WHATWG-compliant URL parser
if ( ! filter_var( $redirect_url, FILTER_VALIDATE_URL ) ) {
$this->set_error( $request, new HttpError( 'Invalid redirect URL' ) );
continue;
}
$this->events[ $request->id ][ Client::EVENT_REDIRECT ] = true;
$this->enqueue( new Request( $redirect_url, [ 'redirected_from' => $request ] ) );
}
}
/**
* Parses an HTTP headers string into an array containing the status and headers.
*
* @param string $headers The HTTP headers to parse.
*
* @return array An array containing the parsed status and headers.
*/
private function parse_http_headers( string $headers ) {
$lines = explode( "\r\n", $headers );
$status = array_shift( $lines );
$status = explode( ' ', $status );
$status = array(
'protocol' => $status[0],
'code' => $status[1],
'message' => $status[2],
);
$headers = array();
foreach ( $lines as $line ) {
if ( strpos( $line, ': ' ) === false ) {
// @TODO: Error, not a valid response
continue;
}
$line = explode( ': ', $line );
/**
* Headers names are case-insensitive.
*
* RFC 7230 states:
*
* > Each header field consists of a case-insensitive field name followed by a colon (":"),
* > optional leading whitespace, the field value, and optional trailing whitespace."
*/
$headers[ strtolower( $line[0] ) ] = $line[1];
}
return array(
'status' => $status,
'headers' => $headers,
);
}
/**
* Opens HTTP or HTTPS streams using stream_socket_client() without blocking,
* and returns nearly immediately.
*
* The act of opening a stream is non-blocking itself. This function uses
* a tcp:// stream wrapper, because both https:// and ssl:// wrappers would block
* until the SSL handshake is complete.
* The actual socket it then switched to non-blocking mode using stream_set_blocking().
*
* @param Request $request The Request to open the socket for.
*
* @return bool Whether the stream was opened successfully.
*/
private function open_nonblocking_http_sockets( $requests ) {
foreach ( $requests as $request ) {
$url = $request->url;
$parts = parse_url( $url );
$scheme = $parts['scheme'];
if ( ! in_array( $scheme, array( 'http', 'https' ) ) ) {
$this->set_error( $request,
new HttpError( 'stream_http_open_nonblocking: Invalid scheme in URL ' . $url . ' – only http:// and https:// URLs are supported' ) );
continue;
}
$is_ssl = $scheme === 'https';
$port = $parts['port'] ?? ( $scheme === 'https' ? 443 : 80 );
$host = $parts['host'];
// Create stream context
$context = stream_context_create(
array(
'socket' => array(
'isSsl' => $is_ssl,
'originalUrl' => $url,
'socketUrl' => 'tcp://' . $host . ':' . $port,
),
)
);
$stream = @stream_socket_client(
'tcp://' . $host . ':' . $port,
$errno,
$errstr,
30,
STREAM_CLIENT_CONNECT | STREAM_CLIENT_ASYNC_CONNECT,
$context
);
if ( $stream === false ) {
$this->set_error( $request,
new HttpError( "stream_http_open_nonblocking: stream_socket_client() was unable to open a stream to $url. $errno: $errstr" ) );
continue;
}
if ( PHP_VERSION_ID >= 72000 ) {
// In PHP <= 7.1 and later, making the socket non-blocking before the
// SSL handshake makes the stream_socket_enable_crypto() call always return
// false. Therefore, we only make the socket non-blocking after the
// SSL handshake.
stream_set_blocking( $stream, 0 );
}
$this->connections[ $request->id ]->http_socket = $stream;
if ( $is_ssl ) {
$request->state = Request::STATE_WILL_ENABLE_CRYPTO;
} else {
$request->state = Request::STATE_WILL_SEND_HEADERS;
}
}
return true;
}
/**
* Prepares an HTTP request string for a given URL.
*
* @param Request $request The Request to prepare the HTTP headers for.
*
* @return string The prepared HTTP request string.
*/
static private function prepare_request_headers( Request $request ) {
$url = $request->url;
$parts = parse_url( $url );
$host = $parts['host'];
$path = ( isset( $parts['path'] ) ? $parts['path'] : '/' ) . ( isset( $parts['query'] ) ? '?' . $parts['query'] : '' );
$headers = [
"Host" => $host,
"User-Agent" => "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/93.0.4577.82 Safari/537.36",
"Accept" => "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9",
"Accept-Encoding" => "gzip",
"Accept-Language" => "en-US,en;q=0.9",
"Connection" => "close",
];
foreach ( $request->headers as $k => $v ) {
$headers[ $k ] = $v;
}
$request_parts = array(
"$request->method $path HTTP/$request->http_version",
);
foreach ( $headers as $name => $value ) {
$request_parts[] = "$name: $value";
}
return implode( "\r\n", $request_parts ) . "\r\n\r\n";
}
private function filter_requests( array $requests, $states ) {
if ( ! is_array( $states ) ) {
$states = [ $states ];
}
$results = [];
foreach ( $requests as $request ) {
if ( in_array( $request->state, $states ) ) {
$results[] = $request;
}
}
return $results;
}
private function stream_select( $requests, $mode ) {
if ( empty( $requests ) ) {
return [];
}
$read = [];
$write = [];
foreach ( $requests as $k => $request ) {
if ( $mode & static::STREAM_SELECT_READ ) {
$read[ $k ] = $this->connections[ $request->id ]->http_socket;
}
if ( $mode & static::STREAM_SELECT_WRITE ) {
$write[ $k ] = $this->connections[ $request->id ]->http_socket;
}
}
$except = null;
// phpcs:disable WordPress.PHP.NoSilencedErrors.Discouraged
$ready = @stream_select( $read, $write, $except, 0, static::NONBLOCKING_TIMEOUT_MICROSECONDS );
if ( $ready === false ) {
foreach ( $requests as $request ) {
$this->set_error( $request, new HttpError( 'Error: ' . error_get_last()['message'] ) );
}
return [];
} elseif ( $ready <= 0 ) {
// @TODO allow at most X stream_select attempts per request
// foreach ( $unprocessed_requests as $request ) {
// $this->>set_error($request, new HttpError( 'stream_select timed out' ));
// }
return [];
}
$selected_requests = [];
foreach ( array_keys( $read ) as $k ) {
$selected_requests[ $k ] = $requests[ $k ];
}
foreach ( array_keys( $write ) as $k ) {
$selected_requests[ $k ] = $requests[ $k ];
}
return $selected_requests;
}
private const STREAM_SELECT_READ = 1;
private const STREAM_SELECT_WRITE = 2;
const EVENT_GOT_HEADERS = 'EVENT_GOT_HEADERS';
const EVENT_BODY_CHUNK_AVAILABLE = 'EVENT_BODY_CHUNK_AVAILABLE';
const EVENT_REDIRECT = 'EVENT_REDIRECT';
const EVENT_FAILED = 'EVENT_FAILED';
const EVENT_FINISHED = 'EVENT_FINISHED';
/**
* Microsecond is 1 millionth of a second.
*
* @var int
*/
const MICROSECONDS_TO_SECONDS = 1000000;
/**
* 5/100th of a second
*/
const NONBLOCKING_TIMEOUT_MICROSECONDS = 0.05 * self::MICROSECONDS_TO_SECONDS;
}