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| 1 | +<?php |
| 2 | + |
| 3 | +namespace React\Socket; |
| 4 | + |
| 5 | +use Evenement\EventEmitter; |
| 6 | + |
| 7 | +/** |
| 8 | + * The `LimitingServer` decorator wraps a given `ServerInterface` and is responsible |
| 9 | + * for limiting and keeping track of open connections to this server instance. |
| 10 | + * |
| 11 | + * Whenever the underlying server emits a `connection` event, it will check its |
| 12 | + * limits and then either |
| 13 | + * - keep track of this connection by adding it to the list of |
| 14 | + * open connections and then forward the `connection` event |
| 15 | + * - or reject (close) the connection when its limits are exceeded and will |
| 16 | + * forward an `error` event instead. |
| 17 | + * |
| 18 | + * Whenever a connection closes, it will remove this connection from the list of |
| 19 | + * open connections. |
| 20 | + * |
| 21 | + * ```php |
| 22 | + * $server = new LimitingServer($server, 100); |
| 23 | + * $server->on('connection', function (ConnectionInterface $connection) { |
| 24 | + * $connection->write('hello there!' . PHP_EOL); |
| 25 | + * … |
| 26 | + * }); |
| 27 | + * ``` |
| 28 | + * |
| 29 | + * See also the `ServerInterface` for more details. |
| 30 | + * |
| 31 | + * @see ServerInterface |
| 32 | + * @see ConnectionInterface |
| 33 | + */ |
| 34 | +class LimitingServer extends EventEmitter implements ServerInterface |
| 35 | +{ |
| 36 | + private $connections = array(); |
| 37 | + private $server; |
| 38 | + private $limit; |
| 39 | + |
| 40 | + private $pauseOnLimit = false; |
| 41 | + private $autoPaused = false; |
| 42 | + private $manuPaused = false; |
| 43 | + |
| 44 | + /** |
| 45 | + * Instantiates a new LimitingServer. |
| 46 | + * |
| 47 | + * You have to pass a maximum number of open connections to ensure |
| 48 | + * the server will automatically reject (close) connections once this limit |
| 49 | + * is exceeded. In this case, it will emit an `error` event to inform about |
| 50 | + * this and no `connection` event will be emitted. |
| 51 | + * |
| 52 | + * ```php |
| 53 | + * $server = new LimitingServer($server, 100); |
| 54 | + * $server->on('connection', function (ConnectionInterface $connection) { |
| 55 | + * $connection->write('hello there!' . PHP_EOL); |
| 56 | + * … |
| 57 | + * }); |
| 58 | + * ``` |
| 59 | + * |
| 60 | + * You MAY pass a `null` limit in order to put no limit on the number of |
| 61 | + * open connections and keep accepting new connection until you run out of |
| 62 | + * operating system resources (such as open file handles). This may be |
| 63 | + * useful it you do not want to take care of applying a limit but still want |
| 64 | + * to use the `getConnections()` method. |
| 65 | + * |
| 66 | + * You can optionally configure the server to pause accepting new |
| 67 | + * connections once the connection limit is reached. In this case, it will |
| 68 | + * pause the underlying server and no longer process any new connections at |
| 69 | + * all, thus also no longer closing any excessive connections. |
| 70 | + * The underlying operating system is responsible for keeping a backlog of |
| 71 | + * pending connections until its limit is reached, at which point it will |
| 72 | + * start rejecting further connections. |
| 73 | + * Once the server is below the connection limit, it will continue consuming |
| 74 | + * connections from the backlog and will process any outstanding data on |
| 75 | + * each connection. |
| 76 | + * This mode may be useful for some protocols that are designed to wait for |
| 77 | + * a response message (such as HTTP), but may be less useful for other |
| 78 | + * protocols that demand immediate responses (such as a "welcome" message in |
| 79 | + * an interactive chat). |
| 80 | + * |
| 81 | + * ```php |
| 82 | + * $server = new LimitingServer($server, 100, true); |
| 83 | + * $server->on('connection', function (ConnectionInterface $connection) { |
| 84 | + * $connection->write('hello there!' . PHP_EOL); |
| 85 | + * … |
| 86 | + * }); |
| 87 | + * ``` |
| 88 | + * |
| 89 | + * @param ServerInterface $server |
| 90 | + * @param int|null $connectionLimit |
| 91 | + * @param bool $pauseOnLimit |
| 92 | + */ |
| 93 | + public function __construct(ServerInterface $server, $connectionLimit, $pauseOnLimit = false) |
| 94 | + { |
| 95 | + $this->server = $server; |
| 96 | + $this->limit = $connectionLimit; |
| 97 | + if ($connectionLimit !== null) { |
| 98 | + $this->pauseOnLimit = $pauseOnLimit; |
| 99 | + } |
| 100 | + |
| 101 | + $this->server->on('connection', array($this, 'handleConnection')); |
| 102 | + $this->server->on('error', array($this, 'handleError')); |
| 103 | + } |
| 104 | + |
| 105 | + /** |
| 106 | + * Returns an array with all currently active connections |
| 107 | + * |
| 108 | + * ```php |
| 109 | + * foreach ($server->getConnection() as $connection) { |
| 110 | + * $connection->write('Hi!'); |
| 111 | + * } |
| 112 | + * ``` |
| 113 | + * |
| 114 | + * @return ConnectionInterface[] |
| 115 | + */ |
| 116 | + public function getConnections() |
| 117 | + { |
| 118 | + return $this->connections; |
| 119 | + } |
| 120 | + |
| 121 | + public function getAddress() |
| 122 | + { |
| 123 | + return $this->server->getAddress(); |
| 124 | + } |
| 125 | + |
| 126 | + public function pause() |
| 127 | + { |
| 128 | + if (!$this->manuPaused) { |
| 129 | + $this->manuPaused = true; |
| 130 | + |
| 131 | + if (!$this->autoPaused) { |
| 132 | + $this->server->pause(); |
| 133 | + } |
| 134 | + } |
| 135 | + } |
| 136 | + |
| 137 | + public function resume() |
| 138 | + { |
| 139 | + if ($this->manuPaused) { |
| 140 | + $this->manuPaused = false; |
| 141 | + |
| 142 | + if (!$this->autoPaused) { |
| 143 | + $this->server->resume(); |
| 144 | + } |
| 145 | + } |
| 146 | + } |
| 147 | + |
| 148 | + public function close() |
| 149 | + { |
| 150 | + $this->server->close(); |
| 151 | + } |
| 152 | + |
| 153 | + /** @internal */ |
| 154 | + public function handleConnection(ConnectionInterface $connection) |
| 155 | + { |
| 156 | + // close connection if limit exceeded |
| 157 | + if ($this->limit !== null && count($this->connections) >= $this->limit) { |
| 158 | + $this->handleError(new \OverflowException('Connection closed because server reached connection limit')); |
| 159 | + $connection->close(); |
| 160 | + return; |
| 161 | + } |
| 162 | + |
| 163 | + $this->connections[] = $connection; |
| 164 | + $that = $this; |
| 165 | + $connection->on('close', function () use ($that, $connection) { |
| 166 | + $that->handleDisconnection($connection); |
| 167 | + }); |
| 168 | + |
| 169 | + // pause accepting new connections if limit exceeded |
| 170 | + if ($this->pauseOnLimit && !$this->autoPaused && count($this->connections) >= $this->limit) { |
| 171 | + $this->autoPaused = true; |
| 172 | + |
| 173 | + if (!$this->manuPaused) { |
| 174 | + $this->server->pause(); |
| 175 | + } |
| 176 | + } |
| 177 | + |
| 178 | + $this->emit('connection', array($connection)); |
| 179 | + } |
| 180 | + |
| 181 | + /** @internal */ |
| 182 | + public function handleDisconnection(ConnectionInterface $connection) |
| 183 | + { |
| 184 | + unset($this->connections[array_search($connection, $this->connections)]); |
| 185 | + |
| 186 | + // continue accepting new connection if below limit |
| 187 | + if ($this->autoPaused && count($this->connections) < $this->limit) { |
| 188 | + $this->autoPaused = false; |
| 189 | + |
| 190 | + if (!$this->manuPaused) { |
| 191 | + $this->server->resume(); |
| 192 | + } |
| 193 | + } |
| 194 | + } |
| 195 | + |
| 196 | + /** @internal */ |
| 197 | + public function handleError(\Exception $error) |
| 198 | + { |
| 199 | + $this->emit('error', array($error)); |
| 200 | + } |
| 201 | +} |
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