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/**
*
*/
package uk.org.ury.server;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.net.MalformedURLException;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.URL;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.List;
import java.util.HashMap;
import java.util.Map;
import uk.org.ury.config.ConfigReader;
import uk.org.ury.database.DatabaseDriver;
import uk.org.ury.database.UserClass;
import uk.org.ury.database.exceptions.ConnectionFailureException;
import uk.org.ury.database.exceptions.MissingCredentialsException;
import uk.org.ury.server.exceptions.HandleFailureException;
/**
* The unified URY server, accepting requests over HTTP.
*
* @author Matt Windsor
*/
public class Server
{
private ServerSocket serverSocket;
private static final String HTTP_VERSION = "HTTP/1.1";
private static final String SERVER_VERSION = "SLUT 0.0";
private static final String DOCTYPE =
"<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\""
+ "\"http://www.w3.org/TR/html4/strict.dtd\">";
private static final String INDEX_HTML =
"\n<html>"
+ "\n <head>"
+ "\n <title>" + SERVER_VERSION + "</title>"
+ "\n </head>"
+ "\n <body>"
+ "\n <h1>Welcome to the " + SERVER_VERSION + " server</h1>"
+ "\n <p>This server exposes a class-based API for accessing"
+ "\n the internals of the " + SERVER_VERSION + " system.</p>"
+ "\n <p>See the documentation for details.</p>"
+ "\n </body>"
+ "\n</html>";
/**
* The main method, which serves to create a server.
*
* @param args The argument vector.
*/
public static void
main (String[] args)
{
Server srv = new Server ();
srv.run ();
}
/**
* Run the server.
*/
private void
run ()
{
try
{
serverSocket = new ServerSocket (8000);
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace ();
}
Socket clientSocket = null;
while (true)
{
System.out.println ("Accepting connections... bring 'em on!");
try
{
clientSocket = serverSocket.accept ();
}
catch (IOException e)
{
System.out.println ("SLUT: Accept failed on port 8000. I'm bailing.");
System.exit (-1);
}
try
{
doConnection (clientSocket);
}
catch (IOException e)
{
e.printStackTrace ();
}
finally
{
try
{
clientSocket.close ();
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
public void
doConnection (Socket clientSocket)
throws IOException
{
PrintWriter out = new PrintWriter (clientSocket.getOutputStream(), true);
BufferedReader in = new BufferedReader (new InputStreamReader (
clientSocket.getInputStream()));
String inputLine;
//initiate conversation with client
List<String> buffer = new ArrayList<String> ();
for (inputLine = in.readLine (); inputLine != null; inputLine = in.readLine ())
{
if (inputLine.equals (""))
break;
buffer.add (inputLine);
if (inputLine.startsWith ("Expect:")
&& inputLine.split (":")[1].startsWith ("100-continue"))
out.print ("HTTP/1.1 100 Continue\n\r\n");
out.flush ();
}
processBuffer (buffer, out);
out.flush ();
out.close ();
in.close ();
System.out.println ("Just finished with this one...");
}
public void
processBuffer (List<String> buffer, PrintWriter out)
{
String requestStart = buffer.get (0);
System.out.println (requestStart);
if (requestStart.startsWith ("GET"))
{
System.out.println ("That was a GET...");
handleGet (buffer, out);
}
else
{
System.out.println ("Uh-oh! I don't know what to do!");
out.println (HTTP_VERSION + " 501 Not Implemented");
out.println ("Connection: close");
out.print ("\r\n");
}
}
public void
handleGet (List<String> buffer, PrintWriter out)
{
String[] getsplit = buffer.get (0).split (" ");
String path = getsplit[1];
if (path.equals ("/index.html")
|| path.equals ("/"))
{
// Someone's trying to get the index page!
// Humour them.
out.println (HTTP_VERSION + " 200 OK");
out.println ("Connection: close");
out.print ("\r\n");
out.println (DOCTYPE + INDEX_HTML);
}
else
{
// Convert this into a URL and fan out the various parts of it.
URL pathURL = null;
try
{
pathURL = new URL ("http://localhost" + path);
}
catch (MalformedURLException e1)
{
serveError (400, "Malformed URL.", out);
}
String className = "uk.org.ury" + pathURL.getPath ().replace ('/', '.');
System.out.println (className);
Class<?> newClass = null;
try
{
newClass = Class.forName (className);
}
catch (ClassNotFoundException e)
{
serveError (404, "Class " + className + " not found.", out);
return;
}
if (RequestHandler.class.isAssignableFrom (newClass))
{
String queryString = pathURL.getQuery ();
Map<String, String> parameters;
try
{
parameters = parseQueryString (queryString);
}
catch (UnsupportedEncodingException e)
{
serveError (500, "URL decode failure for class "
+ className
+ " (" + e.getMessage () + ").", out);
return;
}
List<String> response;
try
{
RequestHandler srh = ((RequestHandler) newClass.newInstance ());
response = srh.handleGetRequest (parameters, this);
}
catch (InstantiationException e)
{
serveError (500, "Instantiation exception for class "
+ className
+ " (" + e.getMessage () + ").", out);
return;
}
catch (IllegalAccessException e)
{
serveError (500, "Illegal access exception for class "
+ className
+ " (" + e.getMessage () + ").", out);
return;
}
catch (HandleFailureException e)
{
serveError (500, "Failed to handle request for class "
+ className
+ " (" + e.getMessage () + ").", out);
return;
}
// If we made it this far, the response is A-OK.
out.println (HTTP_VERSION + " 200 OK");
out.println ("Content-Type: text/plain");
out.print ("\r\n");
out.println ("START");
for (String line : response)
out.println (line);
out.println ("END");
out.flush ();
}
else
{
serveError (404, "Class " + className + " does not handle requests.", out);
return;
}
}
}
/**
* Serve a HTTP plain-text error.
*
* @param code HTTP status code to use.
* @param reason The reason to display to the client.
* @param out The output stream.
*/
private void
serveError (int code, String reason, PrintWriter out)
{
String errorStatus = "";
switch (code)
{
case 400:
errorStatus = "400 Bad Request";
break;
case 404:
errorStatus = "404 Not Found";
break;
default:
errorStatus = "500 Internal Server Error";
break;
}
out.println (HTTP_VERSION + " " + errorStatus);
out.println ("Content-Type: text/plain");
out.println ("Connection: close");
out.print ("\r\n");
out.println ("ERROR: " + reason);
out.flush ();
}
/**
* Parse a query string, populating a key-value map of the
* URL-unescaped results.
*
* @param query The query string to parse.
*
* @return A map associating parameter keys and values.
*
* @throws UnsupportedEncodingException if the URL decoder
* fails.
*/
public Map<String, String>
parseQueryString (String query)
throws UnsupportedEncodingException
{
Map<String, String> params = new HashMap<String, String> ();
// At least one parameter
if (query != null
&& query.endsWith ("&") == false)
{
String[] qsplit = {query};
// More than one parameter - split the query.
if (query.contains ("&"))
qsplit = query.split ("&");
for (String param : qsplit)
{
// Has a value
if (param.contains ("=")
&& param.endsWith ("=") == false)
{
String[] paramsplit = param.split ("=");
params.put (URLDecoder.decode (paramsplit[0], "UTF-8"),
URLDecoder.decode (paramsplit[1], "UTF-8"));
}
// Doesn't have a value
else if (param.contains ("=") == false)
{
params.put (URLDecoder.decode (param, "UTF-8"), null);
}
}
}
return params;
}
/**
* Get a database connection using the given user class.
*
* @param userClass The user class to get a connection for.
*
* @return a database connection, which may or may not
* have been created on this call.
*
* @throw MissingCredentialsException if the credentials
* for the given userclass are missing.
*
* @throw ConnectionFailureException if the connection
* failed.
*/
public DatabaseDriver
getDatabaseConnection (UserClass userClass)
throws MissingCredentialsException, ConnectionFailureException
{
// TODO: Singleton
ConfigReader config = new ConfigReader ("res/conf.xml");
return new DatabaseDriver (config, UserClass.READ_ONLY);
}
/**
* @return the version string of the server.
*/
public String
getVersion ()
{
return SERVER_VERSION;
}
}
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