feature: basic functionality

Author: Greg Bowler

src/Cache.php

@@ -2,22 +2,31 @@
 namespace Gt\FileCache;
 
 class Cache {
+	private FileAccess $fileAccess;
+
 	public function __construct(
-		private string $path = "cache"
+		string $path = "cache",
+		?FileAccess $fileAccess = null,
 	) {
-		if(!is_dir($path)) {
-			mkdir($path, 0775, true);
+		if(is_null($fileAccess)) {
+			$fileAccess = new FileAccess($path);
 		}
+		$this->fileAccess = $fileAccess;
 	}
 
-	public function get(string $name, callable $callback):mixed {
-		$fileName = $this->path . "/$name";
-		if(file_exists($fileName)) {
-			return unserialize(file_get_contents($fileName));
+	public function get(
+		string $name,
+		callable $callback,
+		int $secondsValid = 60 * 60 // 1 hour of validity
+	):mixed {
+		try {
+			$this->fileAccess->checkValidity($name, $secondsValid);
+			return $this->fileAccess->getData($name);
+		}
+		catch(FileNotFoundException|CacheInvalidException) {
+			$value = $callback();
+			$this->fileAccess->setData($name, $value);
+			return $value;
 		}
-
-		$value = $callback();
-		file_put_contents($fileName, serialize($value));
-		return $value;
 	}
 }

src/CacheInvalidException.php

@@ -0,0 +1,6 @@
+<?php
+namespace Gt\FileCache;
+
+class CacheInvalidException extends FileCacheException {
+
+}

src/FileAccess.php

@@ -0,0 +1,38 @@
+<?php
+namespace Gt\FileCache;
+
+class FileAccess {
+	public function __construct(
+		private readonly string $dirPath
+	) {
+	}
+
+	public function getData(string $name):mixed {
+		$filePath = "$this->dirPath/$name";
+		if(!is_file($filePath)) {
+			throw new FileNotFoundException($filePath);
+		}
+
+		$contents = file_get_contents($filePath);
+		return unserialize($contents);
+	}
+
+	public function setData(string $name, mixed $value):void {
+		if(!is_dir($this->dirPath)) {
+			mkdir($this->dirPath, 0775, true);
+		}
+		$filePath = "$this->dirPath/$name";
+		file_put_contents($filePath, serialize($value));
+	}
+
+	public function checkValidity(string $name, int $secondsValidity):void {
+		$filePath = "$this->dirPath/$name";
+		if(!is_file($filePath)) {
+			throw new CacheInvalidException("$filePath (does not exist)");
+		}
+		$fileModifiedTimestamp = filemtime($filePath);
+		if($fileModifiedTimestamp <= time() - $secondsValidity) {
+			throw new CacheInvalidException($filePath);
+		}
+	}
+}

src/FileCacheException.php

@@ -0,0 +1,8 @@
+<?php
+namespace Gt\FileCache;
+
+use RuntimeException;
+
+class FileCacheException extends RuntimeException {
+
+}

src/FileNotFoundException.php

@@ -0,0 +1,7 @@
+<?php
+namespace Gt\FileCache;
+
+class FileNotFoundException extends FileCacheException {
+	public function __construct(string $name) {
+	}
+}