Refactored the whole code

.styleci.yml

@@ -1,4 +1 @@
-preset: psr2
-
-enabled:
-  - length_ordered_imports
+preset: psr12

composer.json

@@ -10,11 +10,12 @@
   "authors": [
     {
       "name": "Alex Plekhanov",
-      "email": "alex@plekhanov.us"
+      "email": "alex@plekhanov.dev"
     }
   ],
   "require": {
-    "php": ">=5.4.0"
+    "php": ">=7.4.0",
+    "ext-json": "*"
   },
   "autoload": {
     "psr-4": {

isup

@@ -1,23 +1,31 @@
 #! /usr/bin/env php
 <?php
 
+declare(strict_types=1);
+
+use Alexsoft\Isup\Check;
+use Alexsoft\Isup\Client\IsItUpOrgClient;
+use Alexsoft\Isup\Logger\EchoLogger;
 
 if (file_exists(__DIR__.'/../../autoload.php')) {
     require __DIR__.'/../../autoload.php';
 } else {
     require __DIR__.'/vendor/autoload.php';
 }
 
+$logger = new EchoLogger();
+
 if ($argc < 2) {
-    echo "Please specify site you want to check!\n";
+    $logger->write('Please specify site you want to check!');
     exit(1);
 }
 
-$domains = $argv;
-array_shift($domains);
+$domains = array_slice($argv, 1);
+
+$checker = new Check(new IsItUpOrgClient(), $logger);
 
 foreach ($domains as $domain) {
-    (new Alexsoft\Isup\Check)->check($domain);
+    $checker->check($domain);
 }
 
-exit(0);
+exit(0);

src/Check.php

@@ -1,47 +1,64 @@
 <?php
+
+declare(strict_types=1);
+
 namespace Alexsoft\Isup;
 
+use Alexsoft\Isup\Client\ClientInterface;
+use Alexsoft\Isup\Exceptions\ApiException;
+use Alexsoft\Isup\Exceptions\UnexpectedResponseStatusException;
+use Alexsoft\Isup\Logger\LoggerInterface;
+
 class Check
 {
-    const STATUS_WEBSITE_IS_UP   = 1;
-    const STATUS_WEBSITE_IS_DOWN = 2;
-    const STATUS_NOT_WEBSITE     = 3;
-    const STATUS_API_ERROR       = 4;
-
-    private $messages = [
-        self::STATUS_WEBSITE_IS_UP   => 'It\'s just you. %s is up.',
-        self::STATUS_WEBSITE_IS_DOWN => 'It\'s not just you! %s looks down from here.',
-        self::STATUS_NOT_WEBSITE     => 'Huh? %s doesn\'t look like a site.',
-        self::STATUS_API_ERROR       => 'Sorry! API is not available right now!'
+    private const STATUS_WEBSITE_IS_UP = 1;
+    private const STATUS_WEBSITE_IS_DOWN = 2;
+    private const STATUS_NOT_WEBSITE = 3;
+    private const STATUS_API_ERROR = 4;
+    private const MESSAGES = [
+        self::STATUS_WEBSITE_IS_UP => "It's just you. %s is up.",
+        self::STATUS_WEBSITE_IS_DOWN => "It's not just you! %s looks down from here.",
+        self::STATUS_NOT_WEBSITE => "Huh? %s doesn't look like a site.",
+        self::STATUS_API_ERROR => 'Sorry! API is not available right now!',
     ];
 
-    protected $url = 'http://isitup.org/%s.json';
+    private ClientInterface $client;
 
-    public function check($domain)
+    private LoggerInterface $logger;
+
+    public function __construct(ClientInterface $client, LoggerInterface $logger)
+    {
+        $this->client = $client;
+        $this->logger = $logger;
+    }
+
+    public function check($domain): void
     {
         $status = $this->getStatus($domain);
 
-        echo sprintf($this->messages[$status], $domain);
-        echo "\n";
+        $this->logger->write(sprintf($this->getMessagePattern($status), $domain));
     }
 
-    protected function getStatus($domain)
+    private function getStatus($domain): int
     {
-        $opts = [
-            'http' => array(
-                'method' => "GET",
-                'header' => "User-Agent: github.com/alexsoft/isup.php\r\n"
-            )
-        ];
-
-        $context = stream_context_create($opts);
+        try {
+            $content = $this->client->getContent($domain);
 
-        $content = json_decode(file_get_contents(sprintf($this->url, $domain), false, $context), true);
+            return (int)$content['status_code'];
+        } catch (ApiException $exception) {
+            return self::STATUS_API_ERROR;
+        }
+    }
 
-        if (false === $content) {
-            return static::STATUS_API_ERROR;
+    /**
+     * @throws UnexpectedResponseStatusException
+     */
+    private function getMessagePattern(int $status): string
+    {
+        if (!array_key_exists($status, self::MESSAGES)) {
+            throw UnexpectedResponseStatusException::withStatus($status);
         }
 
-        return $content['status_code'];
+        return self::MESSAGES[$status];
     }
 }

src/Client/ClientInterface.php

@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Alexsoft\Isup\Client;
+
+interface ClientInterface
+{
+    public function getContent(string $domain): array;
+}

src/Client/IsItUpOrgClient.php

@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Alexsoft\Isup\Client;
+
+use Alexsoft\Isup\Exceptions\ApiException;
+use JsonException;
+
+final class IsItUpOrgClient implements ClientInterface
+{
+    private const URL = 'https://isitup.org/%s.json';
+
+    public function getContent(string $domain): array
+    {
+        $opts = [
+            'http' => [
+                'method' => 'GET',
+                'header' => "User-Agent: github.com/alexsoft/isup.php\r\n",
+            ],
+        ];
+
+        $contents = file_get_contents(
+            sprintf(self::URL, $domain),
+            false,
+            stream_context_create($opts)
+        );
+
+        try {
+            return json_decode($contents, true, 512, JSON_THROW_ON_ERROR);
+        } catch (JsonException $exception) {
+            throw new ApiException($contents, 0, $exception);
+        }
+    }
+}

src/Exceptions/ApiException.php

@@ -0,0 +1,11 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Alexsoft\Isup\Exceptions;
+
+use RuntimeException;
+
+class ApiException extends RuntimeException
+{
+}

src/Exceptions/UnexpectedResponseStatusException.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace Alexsoft\Isup\Exceptions;
+
+use RuntimeException;
+
+class UnexpectedResponseStatusException extends RuntimeException
+{
+    public static function withStatus($status)
+    {
+        return new self("Unexpected status [{$status}]");
+    }
+}

src/IsItUpOrgClient.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace Alexsoft\Isup;
+
+final class IsItUpOrgClient
+{
+    public const URL = 'https://isitup.org/%s.json';
+
+    public function getContent($domain)
+    {
+        $opts = [
+            'http' => [
+                'method' => 'GET',
+                'header' => "User-Agent: github.com/alexsoft/isup.php\r\n",
+            ],
+        ];
+
+        $contents = file_get_contents(
+            sprintf(static::URL, $domain),
+            false,
+            stream_context_create($opts)
+        );
+
+        return json_decode($contents, true);
+    }
+}

src/Logger/EchoLogger.php

@@ -0,0 +1,14 @@
+<?php
+
+namespace Alexsoft\Isup\Logger;
+
+final class EchoLogger implements LoggerInterface
+{
+    public function write(string $string, bool $finishWithNewline = true)
+    {
+        echo $string;
+        if ($finishWithNewline) {
+            echo "\n";
+        }
+    }
+}

src/Logger/LoggerInterface.php

@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Alexsoft\Isup\Logger;
+
+interface LoggerInterface
+{
+    public function write(string $string, bool $finishWithNewline = true);
+}