Issue #80: Unable to open large json files on android 2.2 + phonegap 0.9.5

I could not get rid of the url encoding and decoding without hampering some users ability to pass non-ascii characters back to JavaScript.  However, I was able to reduce the amount of data being passed from Java to JavaScript by 40% by decoding common characters that occur in JSON and XML.  These characters will survive the round trip just fine and don't need to be encoded.

This is the best solution I could come up with.  You won't be able to read files as large as you could in 0.9.4 but it will get close and it will support non-ascii characters.

framework/assets/js/phonegap.js.base

@@ -767,8 +767,8 @@ PhoneGap.JSCallback = function() {
             // If callback has JavaScript statement to execute
             if (xmlhttp.status === 200) {
 
-                // Need to url decode the response and replace %20 with a space
+                // Need to url decode the response
-                var msg = decodeURIComponent(xmlhttp.responseText.replace(/\+/g, '%20'));
+                var msg = decodeURIComponent(xmlhttp.responseText);
                 setTimeout(function() {
                     try {
                         var t = eval(msg);

framework/src/com/phonegap/CallbackServer.java

@@ -11,11 +11,14 @@ import java.io.BufferedReader;
 import java.io.DataOutputStream;
 import java.io.IOException;
 import java.io.InputStreamReader;
+import java.io.UnsupportedEncodingException;
 import java.net.ServerSocket;
 import java.net.Socket;
 import java.net.URLEncoder;
 import java.util.LinkedList;
 
+import android.util.Log;
+
 /**
  * This class provides a way for Java to run JavaScript in the web page that has loaded PhoneGap.
  * The CallbackServer class implements an XHR server and a polling server with a list of JavaScript
@@ -42,6 +45,8 @@ import java.util.LinkedList;
  */
 public class CallbackServer implements Runnable {
 	
+	private static final String LOG_TAG = "CallbackServer";
+
 	/**
 	 * The list of JavaScript statements to be sent to JavaScript.
 	 */
@@ -224,8 +229,9 @@ public class CallbackServer implements Runnable {
 									 //System.out.println("CallbackServer -- sending item");
 									 response = "HTTP/1.1 200 OK\r\n\r\n";
 									 String js = this.getJavascript();
-									 if (js != null)
+									 if (js != null) {
-										 response += URLEncoder.encode(js, "UTF-8");
+										 response += encode(js);
+									 }
 								 }
 							 }
 							 else {
@@ -321,4 +327,40 @@ public class CallbackServer implements Runnable {
 		}
 	}
 	
+	/**
+	 * This will encode the return value to JavaScript.  We revert the encoding for 
+	 * common characters that don't require encoding to reduce the size of the string 
+	 * being passed to JavaScript.
+	 * 
+	 * @param value to be encoded
+	 * @return encoded string
+	 */
+	public static String encode(String value) {
+		String encoded = null;
+		try {
+			encoded = URLEncoder.encode(value, "UTF-8")
+				.replaceAll("\\+", " ")
+				.replaceAll("\\%21", "!")
+				.replaceAll("\\%22", "\"")
+				.replaceAll("\\%27", "'")
+				.replaceAll("\\%28", "(")
+				.replaceAll("\\%29", ")")
+				.replaceAll("\\%2C", ",")
+				.replaceAll("\\%3C", "<")
+				.replaceAll("\\%3D", "=")
+				.replaceAll("\\%3E", ">")
+				.replaceAll("\\%3F", "?")
+				.replaceAll("\\%40", "@")
+				.replaceAll("\\%5B", "[")
+				.replaceAll("\\%5D", "]")
+				.replaceAll("\\%7B", "{")
+				.replaceAll("\\%7D", "}")
+				.replaceAll("\\%3A", ":")
+				.replaceAll("\\%7E", "~");
+		} catch (UnsupportedEncodingException e) {
+			Log.e(LOG_TAG, e.getMessage(), e);
+		}
+		return encoded;
+	}
+	
 }