1 files changed, 270 insertions, 0 deletions
diff --git a/src/main/java/com/btr/proxy/selector/pac/UrlPacScriptSource.java b/src/main/java/com/btr/proxy/selector/pac/UrlPacScriptSource.java
new file mode 100644
index 0000000..6ac8faa
--- /dev/null
+++ b/src/main/java/com/btr/proxy/selector/pac/UrlPacScriptSource.java
@@ -0,0 +1,270 @@
+package com.btr.proxy.selector.pac;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.UnsupportedEncodingException;
+import java.net.HttpURLConnection;
+import java.net.MalformedURLException;
+import java.net.Proxy;
+import java.net.URISyntaxException;
+import java.net.URL;
+
+import com.btr.proxy.util.Logger;
+import com.btr.proxy.util.Logger.LogLevel;
+
+/*****************************************************************************
+ * Script source that will load the content of a PAC file from an webserver.
+ * The script content is cached once it was downloaded. 
+ *
+ * @author Bernd Rosstauscher (proxyvole@rosstauscher.de) Copyright 2009
+ ****************************************************************************/
+
+public class UrlPacScriptSource implements PacScriptSource {
+	
+	private static final int DEFAULT_CONNECT_TIMEOUT = 15 * 1000; // seconds
+	private static final int DEFAULT_READ_TIMEOUT = 20 * 1000; // seconds
+	public static final String OVERRIDE_CONNECT_TIMEOUT = "com.btr.proxy.url.connectTimeout";
+	public static final String OVERRIDE_READ_TIMEOUT = "com.btr.proxy.url.readTimeout";
+	
+	private final String scriptUrl;
+	private String scriptContent;
+	private long expireAtMillis;
+	
+	/*************************************************************************
+	 * Constructor
+	 * @param url the URL to download the script from.
+	 ************************************************************************/
+	
+	public UrlPacScriptSource(String url) {
+		super();
+		this.expireAtMillis = 0;
+		this.scriptUrl = url;
+	}
+
+	/*************************************************************************
+	 * getScriptContent
+	 * @see com.btr.proxy.selector.pac.PacScriptSource#getScriptContent()
+	 ************************************************************************/
+
+	public synchronized String getScriptContent() throws IOException {
+		if (this.scriptContent == null || 
+				(this.expireAtMillis > 0 
+						&& this.expireAtMillis > System.currentTimeMillis())) {
+			try {
+				if (this.scriptUrl.startsWith("file:/") || this.scriptUrl.indexOf(":/") == -1) {
+					this.scriptContent = readPacFileContent(this.scriptUrl);
+				} else {
+					this.scriptContent = downloadPacContent(this.scriptUrl);
+				}
+			} catch (IOException e) {
+				Logger.log(getClass(), LogLevel.ERROR, "Loading script failed from: {0} with error {1}", this.scriptUrl, e);
+				this.scriptContent = "";
+				throw e;
+			}
+		}
+		return this.scriptContent;
+	}
+	
+	/*************************************************************************
+	 * Reads a PAC script from a local file.
+	 * @param scriptUrl
+	 * @return the content of the script file.
+	 * @throws IOException 
+	 * @throws URISyntaxException 
+	 ************************************************************************/
+	
+	private String readPacFileContent(String scriptUrl) throws IOException {
+		try {
+			File file = null;
+			if (scriptUrl.indexOf(":/") == -1) {
+				file = new File(scriptUrl);
+			} else {
+				file = new File(new URL(scriptUrl).toURI());
+			}
+			BufferedReader r = new BufferedReader(new FileReader(file));
+			StringBuilder result = new StringBuilder();
+			try {
+				String line; 
+				while ((line = r.readLine()) != null) {
+					result.append(line).append("\n");
+				}
+			} finally {
+				r.close();
+			} 
+			return result.toString();
+		} catch (Exception e) {
+			Logger.log(getClass(), LogLevel.ERROR, "File reading error.", e);
+			throw new IOException(e.getMessage());
+		}
+	}
+
+	/*************************************************************************
+	 * Downloads the script from a webserver.
+	 * @param url the URL to the script file.
+	 * @return the script content.
+	 * @throws IOException on read error.
+	 ************************************************************************/
+	
+	private String downloadPacContent(String url) throws IOException {
+		if (url == null) {
+			throw new IOException("Invalid PAC script URL: null");
+		}
+
+		setPacProxySelectorEnabled(false);
+		
+		HttpURLConnection con = null;
+		try {
+			con = setupHTTPConnection(url);
+			if (con.getResponseCode() != 200) {
+				throw new IOException("Server returned: "+con.getResponseCode()+" "+con.getResponseMessage());
+			}
+			// Read expire date.
+			this.expireAtMillis = con.getExpiration();
+
+			BufferedReader r = getReader(con);
+			String result = readAllContent(r);
+			r.close();
+			return result;
+		} finally {
+			setPacProxySelectorEnabled(true);
+			if (con != null) {
+				con.disconnect();
+			}
+		}
+	}
+
+	/*************************************************************************
+	 * Enables/disables the PAC proxy selector while we download to prevent recursion.
+	 * See issue: 26 in the change tracker.
+	 ************************************************************************/
+	
+	private void setPacProxySelectorEnabled(boolean enable) {
+		PacProxySelector.setEnabled(enable);
+	}
+
+	/*************************************************************************
+	 * Reads the whole content available into a String.
+	 * @param r to read from.
+	 * @return the complete PAC file content.
+	 * @throws IOException
+	 ************************************************************************/
+	
+	private String readAllContent(BufferedReader r) throws IOException {
+		StringBuilder result = new StringBuilder();
+		String line; 
+		while ((line = r.readLine()) != null) {
+			result.append(line).append("\n");
+		}
+		return result.toString();
+	}
+
+	/*************************************************************************
+	 * Build a BufferedReader around the open HTTP connection.
+	 * @param con to read from
+	 * @return the BufferedReader.
+	 * @throws UnsupportedEncodingException
+	 * @throws IOException
+	 ************************************************************************/
+	
+	private BufferedReader getReader(HttpURLConnection con)
+			throws UnsupportedEncodingException, IOException {
+		String charsetName = parseCharsetFromHeader(con.getContentType());
+		BufferedReader r = new BufferedReader(new InputStreamReader(con.getInputStream(), charsetName));
+		return r;
+	}
+
+	/*************************************************************************
+	 * Configure the connection to download from.
+	 * @param url to get the pac file content from
+	 * @return a HTTPUrlConnecion to this url.
+	 * @throws IOException
+	 * @throws MalformedURLException
+	 ************************************************************************/
+	
+	private HttpURLConnection setupHTTPConnection(String url)
+			throws IOException, MalformedURLException {
+		HttpURLConnection con = (HttpURLConnection) new URL(url).openConnection(Proxy.NO_PROXY);
+		con.setConnectTimeout(getTimeOut(OVERRIDE_CONNECT_TIMEOUT, DEFAULT_CONNECT_TIMEOUT));
+        con.setReadTimeout(getTimeOut(OVERRIDE_READ_TIMEOUT, DEFAULT_READ_TIMEOUT));
+		con.setInstanceFollowRedirects(true);
+		con.setRequestProperty("accept", "application/x-ns-proxy-autoconfig, */*;q=0.8");
+		return con;
+	}
+	
+	/*************************************************************************
+	 * Gets the timeout value from a property or uses the given default value if
+	 * the property cannot be parsed.
+	 * @param overrideProperty the property to define the timeout value in milliseconds
+	 * @param defaultValue the default timeout value in milliseconds.
+	 * @return the value to use.
+	 ************************************************************************/
+	
+	protected int getTimeOut(String overrideProperty, int defaultValue) {
+		int timeout = defaultValue; 
+		String prop = System.getProperty(overrideProperty);
+		if (prop != null && prop.trim().length() > 0) {
+			try {
+				timeout = Integer.parseInt(prop.trim());
+			} catch (NumberFormatException e) {
+				Logger.log(getClass(), LogLevel.DEBUG, "Invalid override property : {0}={1}", overrideProperty, prop);
+				// In this case use the default value.
+			}
+		}
+		return timeout;
+	}
+
+	/*************************************************************************
+	 * Response Content-Type could be something like this:   
+	 *    application/x-ns-proxy-autoconfig; charset=UTF-8
+	 * @param contentType header field.
+	 * @return the extracted charset if set else a default charset.
+	 ************************************************************************/
+	
+	String parseCharsetFromHeader(String contentType) {
+		String result = "ISO-8859-1";
+		if (contentType != null) {
+			String[] paramList = contentType.split(";");
+			for (String param : paramList) {
+				if (param.toLowerCase().trim().startsWith("charset") && param.indexOf("=") != -1) {
+					result = param.substring(param.indexOf("=")+1).trim();
+				}
+			}
+		}
+		return result;
+	}
+
+	/***************************************************************************
+	 * @see java.lang.Object#toString()
+	 **************************************************************************/
+	@Override
+	public String toString() {
+		return this.scriptUrl;
+	}
+
+	/*************************************************************************
+	 * isScriptValid
+	 * @see com.btr.proxy.selector.pac.PacScriptSource#isScriptValid()
+	 ************************************************************************/
+	
+	public boolean isScriptValid() {
+		try {
+			String script = getScriptContent();
+			if (script == null || script.trim().length() == 0) {
+				Logger.log(getClass(), LogLevel.DEBUG, "PAC script is empty. Skipping script!");
+				return false;
+			}
+			if (script.indexOf("FindProxyForURL") == -1) {
+				Logger.log(getClass(), LogLevel.DEBUG, "PAC script entry point FindProxyForURL not found. Skipping script!");
+				return false;
+			}
+			return true;
+		} catch (IOException e) {
+			Logger.log(getClass(), LogLevel.DEBUG, "File reading error: {0}", e);
+			return false;
+		}
+	}
+	
+}