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<?php |
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namespace BitWasp\Bitcoin\Networking\Peer; |
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use BitWasp\Bitcoin\Networking\DnsSeeds\DnsSeedList; |
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use BitWasp\Bitcoin\Networking\Ip\Ipv4; |
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use BitWasp\Bitcoin\Networking\Settings\NetworkSettings; |
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use BitWasp\Bitcoin\Networking\Services; |
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use BitWasp\Bitcoin\Networking\Structure\NetworkAddress; |
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use BitWasp\Bitcoin\Networking\Structure\NetworkAddressInterface; |
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use React\Dns\Resolver\Resolver; |
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use React\Promise\Deferred; |
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class Locator |
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{ |
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/** |
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* @var Resolver |
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*/ |
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private $dns; |
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/** |
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* @var DnsSeedList |
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*/ |
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private $seeds; |
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/** |
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* @var NetworkAddressInterface[] |
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*/ |
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private $knownAddresses = []; |
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/** |
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* Locator constructor. |
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* @param Resolver $dns |
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* @param NetworkSettings $settings |
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*/ |
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public function __construct(Resolver $dns, NetworkSettings $settings) |
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{ |
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$this->seeds = $settings->getDnsSeedList(); |
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$this->dns = $dns; |
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$this->settings = $settings; |
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} |
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/** |
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* Takes an arbitrary list of dns seed hostnames, and attempts |
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* to return a list from each. Request fails if any hosts are |
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* offline or cause an error. |
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* |
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* @param array $seeds |
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* @return \React\Promise\Promise|\React\Promise\PromiseInterface |
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*/ |
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public function querySeeds(array $seeds) |
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{ |
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$peerList = new Deferred(); |
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// Connect to $numSeeds peers |
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/** @var Peer[] $vNetAddr */ |
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$vNetAddr = []; |
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$c = 0; |
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foreach ($seeds as $seed) { |
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$this->dns |
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->resolve($seed) |
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->then(function ($ipList) use (&$vNetAddr, $peerList, &$numSeeds, &$c) { |
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$peerList->resolve($ipList); |
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}, function ($error) use ($peerList) { |
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$peerList->reject($error); |
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}) |
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; |
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} |
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// Compile the list of lists of peers into $this->knownAddresses |
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return $peerList->promise(); |
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} |
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/** |
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* Given a number of DNS seeds to query, select a random few and |
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* return their peers. |
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* |
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* @param int $numSeeds |
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* @return \React\Promise\Promise|\React\Promise\PromiseInterface |
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*/ |
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private function getPeerList($numSeeds = 1) |
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{ |
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// Take $numSeeds |
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$seedHosts = $this->seeds->getHosts(); |
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shuffle($seedHosts); |
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$seeds = array_slice($seedHosts, 0, min($numSeeds, count($seedHosts))); |
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return $this->querySeeds($seeds); |
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} |
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/** |
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* Query $numSeeds DNS seeds, returning the NetworkAddress[] result. |
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* Is rejected if any of the seeds fail. |
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* |
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* @param int $numSeeds |
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* @return \React\Promise\Promise|\React\Promise\PromiseInterface |
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*/ |
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public function queryDnsSeeds($numSeeds = 1) |
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{ |
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$deferred = new Deferred(); |
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$this |
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->getPeerList($numSeeds) |
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->then( |
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function (array $vPeerVAddrs) use ($deferred) { |
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shuffle($vPeerVAddrs); |
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/** @var NetworkAddressInterface[] $addresses */ |
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$addresses = []; |
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foreach ($vPeerVAddrs as $ip) { |
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$addresses[] = new NetworkAddress( |
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Services::NETWORK, |
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new Ipv4($ip), |
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$this->settings->getDefaultP2PPort() |
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); |
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} |
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$this->knownAddresses = array_merge( |
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$this->knownAddresses, |
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$addresses |
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); |
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$deferred->resolve($this); |
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}, |
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function ($error) use ($deferred) { |
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$deferred->reject($error); |
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} |
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) |
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; |
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return $deferred->promise(); |
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} |
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/** |
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* @return NetworkAddressInterface[] |
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*/ |
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public function getKnownAddresses() |
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{ |
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return $this->knownAddresses; |
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} |
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/** |
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* Pop an address from the discovered peers |
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* |
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* @return NetworkAddressInterface |
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* @throws \Exception |
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*/ |
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public function popAddress() |
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{ |
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if (count($this->knownAddresses) < 1) { |
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throw new \Exception('No peers'); |
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} |
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return array_pop($this->knownAddresses); |
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} |
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} |
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In PHP it is possible to write to properties without declaring them. For example, the following is perfectly valid PHP code:
Generally, it is a good practice to explictly declare properties to avoid accidental typos and provide IDE auto-completion: