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Chris Pollett >
Old Classes
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HW5 Solutions Page
This solution was heavily modified from student DK's solution.
Good work DK!
<!-- test.html -->
<html>
<head>
<title>test.html</title>
</head>
<body>
<p>test</p>
</body>
</html>
#!/usr/bin/perl
#
# test.cgi
#
# This cgi-script can be used to output the CGI environment
# variables and also act as a counter of number of times it
# has been accessed
#
$countFile = "counter.txt"; # file counter stored in
print <<HTML_BLOCK;
Content-type:text/html
<html>
<head>
<title>Environment + Counter</title>
</head>
<body>
<p><h3>Environment + Counter</h3></p>
<table border="2">
HTML_BLOCK
foreach (sort keys %ENV)
{
print " <tr><td> $_ </td><td> $ENV{$_}</td></tr> \n";
}
print " </table> \n";
if(-e $countFile)
{
open(FILE, $countFile) || die "Could not open count file\n";
$count = <FILE>;
close(FILE);
$count++;
}
else
{
$count = 1;
}
open(FILE, ">$countFile") || die "Could not write to count file";
print FILE "$count\n";
close(FILE);
print " <p>You are visitor number: $count</p>";
print <<HTML_BLOCK;
<body>
</html>
HTML_BLOCK
/*
MyServerProperties.txt
*/
port= 5000
host=localhost
public_html = /home/cpollett/Hw5/
cgi_bin = /home/cpollett/Hw5/
// MyWebServer.java -- a simplified web server that can do CGI
import java.io.*;
import java.util.*;
import java.net.*;
/**
MyWebServer
Java web server that serves text htmls and cgi pages
It uses MyServerProperties.txt to read in a property data.
The MyServerProperties file should be formatted in the
following way:
for windows:
port=80
perl=w:/perl/bin/perl
name=computer name
publicHtml = w:/public_html/
cgi_bin = w:/cgi-bin/
for UNIX:
port=80
perl= /usr/bin/perl
name=computer name
publicHtml = /usr/wwwroot/
cgi_bin = /usr/wwwroot/cgi-bin/
@author DK (student) -- heavily modified by C. Pollett
@version 1.0
*/
public class MyWebServer
{
/**
@return the port number
*/
public static int getPort()
{
return port;
}
/**
@return the public_html directory
*/
public static String publicHtml()
{
return publicHtml;
}
/**
@return the cgi_bin directory
*/
public static String getCgiBin()
{
return cgi;
}
/**
Creates a socket and then listens for users
*/
public static void startWebServer()
{
try
{
//calls for the function to read in property file
readConfig("MyServerProperties.txt");
ServerSocket accept = new ServerSocket(port);
System.out.println("Server ready to accept connections.");
while(true)
{
Socket s = accept.accept();
//if someone there create a new thread
ConnectionHandler handler = new ConnectionHandler(s);
handler.start();
}
}
catch (Exception e)
{
System.out.println(e.toString());
System.exit(0);
}
}
/**
Reads in the Property file
@param fileName -- the property file's name
*/
public static void readConfig(String fileName)
{
System.out.println(
"Attempting to read MyServerProperties.txt...");
Properties properties = new Properties();
try
{
FileInputStream file = new FileInputStream(fileName);
properties.load(file);
file.close();
}
catch (IOException ie)
{
System.err.println("Error reading"+
"MyServerProperties.txt configuration file ");
System.err.println(ie.toString());
System.exit(0);
}
port = Integer.parseInt(properties.getProperty("port"));
publicHtml = properties.getProperty("public_html");
cgi = properties.getProperty("cgi_bin");
host= properties.getProperty("host");
System.out.println("MyServerProperties.txt file read.");
}
public static void main(String[] args)
{
startWebServer();
}
public static String publicHtml ; //path to public_html
public static String perl; //path to perl directory
public static String cgi; //path to cgi-bin
public static int port; //port number
public static String host; //path to cgi-bin
}
/**
ConnectionHandler class used to handle an
individual request by a Thread
*/
class ConnectionHandler extends Thread
{
/**
Constructor -- sets the socket involved in this request
@param s -- the socket
*/
public ConnectionHandler(Socket s)
{
socket = s;
}
/**
method that is executed by a thread to handle a single HTTP
request
*/
public void run()
{
try
{
String tmp;
//input stream to get users requests
BufferedReader socketInput = new BufferedReader(
new InputStreamReader(socket.getInputStream()));
//output stream to respond to users requests
DataOutputStream socketOutput =
new DataOutputStream(socket.getOutputStream());
//user Request
String userRequest = socketInput.readLine().toString();
System.out.println("\nRequest:\n"+userRequest);
tmp = socketInput.readLine().toString();
System.out.println(tmp);
String accept = tmp.substring(8);
boolean flag=true;
while(flag)
{
tmp=socketInput.readLine();
System.out.println(tmp);
if(tmp.equalsIgnoreCase("")) flag=false;
}
StringTokenizer token = new StringTokenizer(userRequest);
String getRequest = token.nextToken();
//FILENAME
String fileName = token.nextToken();
//HTTP protocol
http = token.nextToken();
//checks if the user input correct path
if(!fileName.startsWith("/public_html")
&& !fileName.startsWith("/cgi-bin"))
{
printMessage("403", Err403, socketOutput);
}
// we only handle GET requests
else if(getRequest.equals("GET"))
{
if(fileName.startsWith("/public_html"))
sendHtml(http, fileName, socketOutput);
else
executeCgi (fileName, socketOutput, accept);
}
else
printMessage("405", Err405, socketOutput);
//all done socket closed
socket.close();
}
catch(Exception e)
{
System.err.println(e.toString());
}
}
/**
Sends page user requested
@param http -- http protocol user uses
@param fileName -- filename user wanted
@param socketOutput -- DataOutputStream from socket
@throws Exception - exception
*/
public void sendHtml(String http, String fileName,
DataOutputStream socketOutput) throws Exception
{
String httpOutput="";
String tmp;
//if the file is html and exists display it, otherwise error
if(fileName.endsWith(".html"))
{
BufferedReader in = new BufferedReader(
new FileReader(MyWebServer.publicHtml()
+ fileName.substring(12)));
/* read the file line by line into a
string then send the string
*/
while( (tmp = in.readLine())!= null)
httpOutput+=tmp;
printMessage("OK 200", httpOutput, socketOutput);
}
else
{
printMessage("415", Err415, socketOutput);
}
}
/**
executes a cgi script and displays the results
@param fileName file name
@param accept MIME serve accepts*
@param socketOutput DataOutputStream
@throws Exception exception
*/
public void executeCgi(String fileName,
DataOutputStream socketOutput, String accept)
{
String tmp, cgiOutput="";
Runtime runTime = Runtime.getRuntime();
String[] env = getEnvironment(fileName, accept);
try
{
String cmd = MyWebServer.getCgiBin()
+ fileName.substring(9);
Process p = runTime.exec(cmd, env);
String processError="";
//process input stream
BufferedReader stdInput =
new BufferedReader(new InputStreamReader(
p.getInputStream()));
//process error stream
BufferedReader stdError =
new BufferedReader(
new InputStreamReader(p.getErrorStream()));
//gets all the input stream, ie result of execution
while ((tmp = stdInput.readLine()) != null)
cgiOutput+=tmp+"\n";
//gets all if any errors in the execution
while ((tmp = stdError.readLine()) != null)
processError+=tmp;
if(processError.equalsIgnoreCase(""))
printMessage("200 OK", cgiOutput, socketOutput, false);
else
printMessage("500", processError, socketOutput);
}
//catch for the top try
catch (Exception e)
{
System.out.println(e.toString());
}
}
/**
Prints HTTP responses, outputs Content-type as text/html
@param code response code
@param msg response string
@param socketOutput output
@throws Exception exception
*/
public void printMessage(String code, String msg,
DataOutputStream socketOutput) throws Exception
{
printMessage(code, msg, socketOutput, true);
}
/**
Prints HTTP responses
@param code response code
@param msg response string
@param socketOutput output
@param outputType says whether we output the Content-type
as text/html or not
@throws Exception exception
*/
public void printMessage(String code, String msg,
DataOutputStream socketOutput, boolean outputType)
throws Exception
{
socketOutput.writeBytes(http+" "+ code+"\n");
System.out.println("\nResponse:\n"+http +" "+ code + "\n");
socketOutput.writeBytes(
"Server: My Server\n MIME - version: 1.0\n");
System.out.println("Server: My Server\n MIME - version: 1.0\n");
if(outputType)
{
socketOutput.writeBytes("Content-Type: text/html\n");
System.out.println("Content-Type: text/html\n");
socketOutput.writeBytes(
"Content-length:"+ msg.length() + "\n\n");
System.out.println(
"Content-length:"+ msg.length() + "\n\n");
}
socketOutput.writeBytes(msg);
System.out.println(msg);
socketOutput.flush();
}
/**
creates an array of cgi environment variables
@param fileName - user requested filename
@param accept -- connection type
@return array on cgi environmental variables
*/
public String[] getEnvironment(String fileName, String accept)
{
ArrayList env = new ArrayList();
String[] type = new String[1];
String rname = socket.getInetAddress().toString();
String hname = socket.getLocalAddress().toString();
int slash1 = rname.indexOf("/");
int slash2 = hname.indexOf("/");
int qmark = fileName.indexOf("?");
if (qmark < 0 ) qmark = fileName.length();
env.add("SERVER_SOFTWARE=Java Web server");
env.add("SERVER_NAME=" + hname.substring(0, slash2));
env.add("SERVER_PROTOCOL=" + http);
env.add("SERVER_PORT=" + MyWebServer.getPort());
env.add("REQUEST_METHOD=GET");
//request method is always get in this assignment
env.add("SCRIPT_NAME=" + fileName.substring(0, qmark));
if(qmark < fileName.length())
env.add("QUERY_STRING=" + fileName.substring(qmark+1));
else
env.add("QUERY_STRING=");
env.add("REMOTE_HOST=" + rname.substring(0, slash1));
//host contains value from Host header
env.add("REMOTE_ADDR=" + rname.substring(slash1+1));
env.add("HTTP_CONNECTION=" + accept.substring(3));
return ( (String[]) env.toArray(type));
}
private Socket socket;
//http protocol user requested, HTTP/1.0 or something else
private String http = "";
//HTTP error messages
String Err403 = "<h2>ERROR 403 Forbidden </h2>";
String Err404 = "<h2>ERROR 404 Page not found</h2>";
String Err405 = "<h2>ERROR 405 Method not allowed </h2>";
String Err410 = "<h2>ERROR 410 Page Permanently not available</h2>";
String Err415 = "<h2>ERROR 415 Unsupported media type</h2>";
}
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