Implemented Dotenv::parse()

Thanks for @taylorotwell for the name!

Author: GrahamCampbell

README.md

@@ -311,6 +311,24 @@ VAR=value # comment
 ```
 
 
+### Parsing Without Loading
+
+Sometimes you just wanna parse the file and resolve the nested environment variables, by giving us a string, and have an array returned back to you. While this is already possible, it is a little fiddly, so we have provided a direct way to do this:
+
+```php
+// ['FOO' => 'Bar', 'BAZ' => 'Hello Bar']
+Dotenv\Dotenv::parse("FOO=Bar\nBAZ=\"Hello \${FOO}\"");
+```
+
+This is exactly the same as:
+
+```php
+Dotenv\Dotenv::createArrayBacked(__DIR__)->load();
+```
+
+only, instead of providing the directory to find the file, you have directly provided the file contents.
+
+
 ### Usage Notes
 
 When a new developer clones your codebase, they will have an additional

src/Dotenv.php

@@ -9,11 +9,13 @@
 use Dotenv\Loader\LoaderInterface;
 use Dotenv\Parser\Parser;
 use Dotenv\Parser\ParserInterface;
+use Dotenv\Repository\Adapter\ArrayAdapter;
 use Dotenv\Repository\Adapter\PutenvAdapter;
 use Dotenv\Repository\RepositoryBuilder;
 use Dotenv\Repository\RepositoryInterface;
 use Dotenv\Store\StoreBuilder;
 use Dotenv\Store\StoreInterface;
+use Dotenv\Store\StringStore;
 
 class Dotenv
 {
@@ -170,6 +172,44 @@ public static function createUnsafeImmutable($paths, $names = null, bool $shortC
         return self::create($repository, $paths, $names, $shortCircuit, $fileEncoding);
     }
 
+    /**
+     * Create a new dotenv instance with an array backed repository.
+     *
+     * @param string|string[]      $paths
+     * @param string|string[]|null $names
+     * @param bool                 $shortCircuit
+     * @param string|null          $fileEncoding
+     *
+     * @return \Dotenv\Dotenv
+     */
+    public static function createArrayBacked($paths, $names = null, bool $shortCircuit = true, string $fileEncoding = null)
+    {
+        $repository = RepositoryBuilder::createWithNoAdapters()->addAdapter(ArrayAdapter::class)->make();
+
+        return self::create($repository, $paths, $names, $shortCircuit, $fileEncoding);
+    }
+
+    /**
+     * Parse the given content and resolve nested variables.
+     *
+     * This method behaves just like load(), only without mutating your actual
+     * environment. We do this by using an array backed repository.
+     *
+     * @param string $content
+     *
+     * @throws \Dotenv\Exception\InvalidFileException
+     *
+     * @return array<string,string|null>
+     */
+    public static function parse(string $content)
+    {
+        $repository = RepositoryBuilder::createWithNoAdapters()->addAdapter(ArrayAdapter::class)->make();
+
+        $phpdotenv = new self(new StringStore($content), new Parser(), new Loader(), $repository);
+
+        return $phpdotenv->load();
+    }
+
     /**
      * Read and load environment file(s).
      *

src/Store/StringStore.php

@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Dotenv\Store;
+
+final class StringStore implements StoreInterface
+{
+    /**
+     * The file content.
+     *
+     * @var string
+     */
+    private $content;
+
+    /**
+     * Create a new string store instance.
+     *
+     * @param string $content
+     *
+     * @return void
+     */
+    public function __construct(string $content)
+    {
+        $this->content = $content;
+    }
+
+    /**
+     * Read the content of the environment file(s).
+     *
+     * @return string
+     */
+    public function read()
+    {
+        return $this->content;
+    }
+}

tests/Dotenv/DotenvTest.php

@@ -349,4 +349,31 @@ public function testDirectConstructor()
             'NULL'   => '',
         ], $dotenv->load());
     }
+
+    public function testDotenvParseExample1()
+    {
+        $output = Dotenv::parse(
+            "BASE_DIR=\"/var/webroot/project-root\"\nCACHE_DIR=\"\${BASE_DIR}/cache\"\nTMP_DIR=\"\${BASE_DIR}/tmp\"\n"
+        );
+
+        self::assertSame($output, [
+            'BASE_DIR'  => '/var/webroot/project-root',
+            'CACHE_DIR' => '/var/webroot/project-root/cache',
+            'TMP_DIR'   => '/var/webroot/project-root/tmp',
+        ]);
+    }
+
+    public function testDotenvParseExample2()
+    {
+        $output = Dotenv::parse("FOO=Bar\nBAZ=\"Hello \${FOO}\"");
+
+        self::assertSame($output, ['FOO' => 'Bar', 'BAZ' => 'Hello Bar']);
+    }
+
+    public function testDotenvParseEmptyCase()
+    {
+        $output = Dotenv::parse('');
+
+        self::assertSame($output, []);
+    }
 }