Create SimpleCache.java

Author: HiddenMotives

src/SimpleCache.java

@@ -0,0 +1,237 @@
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLConnection;
+import java.util.Date;
+import java.util.Scanner;
+
+
+
+/**
+ * SimpleCache Caching Class Originally published in PHP by: Gilbert Pellegrom
+ * Webpage: https://github.com/gilbitron/PHP-SimpleCache
+ * 
+ * Ported to Java by HiddenMotives
+ * 
+ * Released under the MIT license.
+ * http://www.opensource.org/licenses/mit-license.php
+ * 
+ */
+
+public class SimpleCache {
+    
+    // Cache time is defined in day intervals.
+    private int cache_time = 1;
+    
+    // Directory where cached files will be stored
+    private String cache_path = "cache/";
+    
+    // Extension of the cached files
+    private String cache_extension = ".cache";
+
+    public int get_cache_time () {
+        return this.cache_time;
+    }
+    
+    public String get_cache_path() {
+        return this.cache_path;
+    }
+
+    public String get_cache_extension() {
+        return this.cache_extension;
+    }
+    
+    public void set_cache_time(int days) {
+        this.cache_time = days;
+    }
+
+    public void set_cache_path(String path) {
+        this.cache_path = path;
+        if (!(new File(this.cache_path).isDirectory())) {
+            new File(this.cache_path).mkdirs();
+        }
+    }
+
+    public void set_cache_extension(String ext) {
+        this.cache_extension = ext;
+    }
+
+    /**
+     * Check if a file is cached or not.
+     * @param label
+     * @return 
+     */
+    public boolean is_cached(String label) {
+        String filename = String.valueOf(this.cache_path)
+                + this.safe_filename(label) + this.cache_extension;
+        File file = new File(filename);
+        long diff = new Date().getTime() - file.lastModified();
+        
+        return file.exists() && (!(diff > (long) this.cache_time * 24 * 60 * 60 
+                * 1000));
+    }
+
+    /**
+     * Function that allows you to grab the cache from a label.
+     * @param label
+     * @return 
+     */
+    public String get_cache(String label) {
+        if (this.is_cached(label)) {
+            String filename = String.valueOf(this.cache_path)
+                    + this.safe_filename(label) + this.cache_extension;
+
+            String data;
+            try (Scanner reader = new Scanner(new File(filename)).useDelimiter("\\Z")) {
+                data = reader.next();
+                reader.close();
+                return data;
+            } catch (FileNotFoundException e) {
+                return null;
+            }
+        }
+        
+        return null;
+    }
+
+    /**
+     * Set a cache file using a custom label and predefined data.
+     * @param label
+     * @param data 
+     */
+    public void set_cache(String label, String data) {
+        try (Writer writer = new BufferedWriter(new OutputStreamWriter(
+                new FileOutputStream(this.cache_path
+                        + this.safe_filename(label) + this.cache_extension),
+                "utf-8"))) {
+            writer.write(data);
+            writer.close();
+        } catch (IOException ex) {
+            System.out.println(ex.getMessage());
+        }
+    }
+    
+    /**
+     * Function that tries to cached data, if no cached file is found it will
+     * try and cache the data from the URL.
+     * 
+     * @param label Label of the cached file
+     * @param url
+     * @return
+     * @throws MalformedURLException
+     * @throws IOException 
+     */
+    public String get_data(String label, String url)
+            throws MalformedURLException, IOException {
+        String data = null;
+
+        if (this.get_cache(label) != null) {
+            data = this.get_cache(label);
+            return data;
+        }
+
+        data = this.grab_url(url);
+        this.set_cache(label, data);
+        return data;
+    }
+    
+    /**
+     * Function that reads and returns the contents of a URL.
+     * Using the specified user agent and timeout when making the URL request.
+     * @param url
+     * @param timeout in milliseconds
+     * @param userAgent
+     * @return Contents of the URL.
+     * @throws MalformedURLException
+     * @throws IOException 
+     */
+    public String grab_url(String url, int timeout, String userAgent)
+            throws MalformedURLException, IOException {
+        StringBuilder response = new StringBuilder();
+        URL website = new URL(url);
+        URLConnection connection = website.openConnection();
+        connection.setConnectTimeout(timeout);
+        connection.setRequestProperty("User-Agent", userAgent);
+        try (BufferedReader in = new BufferedReader(
+                new InputStreamReader(
+                        connection.getInputStream()))) {
+            while ((url = in.readLine()) != null) {
+                response.append(url);
+            }
+            
+            in.close();
+        }
+
+        return response.toString();
+    }
+
+    /**
+     * Function that reads and returns the contents of a URL.
+     * @param url
+     * @return Contents of the URL
+     * @throws MalformedURLException
+     * @throws IOException 
+     */
+    public String grab_url(String url) throws MalformedURLException,
+            IOException {
+        StringBuilder response = new StringBuilder();
+        URL website = new URL(url);
+        URLConnection connection = website.openConnection();
+        connection.setConnectTimeout(5000);
+        try (BufferedReader in = new BufferedReader(
+                new InputStreamReader(
+                        connection.getInputStream()))) {
+            while ((url = in.readLine()) != null) {
+                response.append(url);
+            }
+            
+            in.close();
+        }
+        return response.toString();
+    }
+
+    /**
+     * Remove all Cached files
+     */
+    public void clearCache() {
+        for (File file : new File(this.cache_path).listFiles()) {
+            file.delete();
+        }
+    }
+    
+    public void clearCache(String label) throws FileNotFoundException {
+        String filename = String.valueOf(this.cache_path)
+                    + this.safe_filename(label) + this.cache_extension;
+        File file = new File(filename);
+        if(file.exists()) {
+            file.delete();
+        } else {
+            throw new FileNotFoundException();
+        }   
+    }
+
+    /**
+     * Function the number of cached files currently stored
+     * @return total cached files
+     */
+    public int get_total_cached() {
+        return new File(this.cache_path).listFiles().length;
+    }
+
+    /**
+     * Helper function to help validate file names
+     * @param filename
+     * @return
+     */
+    private String safe_filename(String filename) {
+        return filename.replaceAll("/[^0-9a-z\\.\\_\\-]/i", "");
+    }
+}