Description:

The goal of this assignment is to allow you to demonstrate your knowledge of HTTP requests and HTTP responses. Well be implementing a simple HTTP client and a simple HTTP server running version of HTTP/1.0. The goal is to get familiar with requests generated by your favorite web browser and responses from real web servers.

HTTPClient

• Your client should be named HTTPClient.java should or HTTPClient.py
• You are going to implement two methods of HTTP: GET and PUT.
• Your client take command line arguments specifying the needed parameters as follow for each operation.
• Get

o Use the HTTP client to request data from a web server. Your client should be able to send requests and receive responses from any web server on the Internet. There is no need to write a server program to communicate with the client with GET command. o Your client should accept a single command-line argument: URL, which is the URL that it will request. There is no need to define GET command in the command line here.

• The URL will be given in the following format:

http://hostname[:port][/path] (only lowercase letters will be used)

• hostname the web servers hostname
• :port an optional port, if not present, use port 80.
• path the path from the web servers main directory to the requested file, if this is not present, then the path is

/

• Example: http://vcu.edu/index.html
  • If any of the arguments are incorrect, exit after printing an error message of the form ERR arg x, where x is the argument number.
  • Treat any URL as valid as long as it starts with http:// o Connect to the host given in the URL at the port given in the URL thru TCP connection.
  • Handle exceptions as you wish for example, if the host doesnt exist or the port given is not open
• Submit a valid GET request for path/file given in the supplied URL using HTTP/1.0.
  • Your request must include the Host field (with the proper entry).
  • Your request must include the Time field (with the proper entry).
  • Your request must also include the User-agent field with the entry VCU-CMSC491.
  • Your request must also include the User-name field with your first name as the entry.
  • No other request fields are needed.
  • Remember to end with extra CR/LF o Print the HTTP request sent to the server.
  • Note: Print the actual string sent to the server.
• Parse the HTTP response header received from the server and print the following information:
  • Response code (number)
  • Server type
  • If the response code is in the 200-level:
    • Last modified date
    • Number of bytes in the response data
    • Store the received file (for example: index.html from http://www.vcu.edu/) in the current directory. If the response code is in the 300-level:
    • The URL where the file is located
  • Print the HTTP response header.
  • In case you successfully received and stored a file, open the stored file using any browser to check it.
  • Once you have this part of the client working, you should test it with the following two test cases:
    1. Use it to get a file of your choosing from a real web server on the

Internet. For example, java HTTPClient http://www.cnn.com/index.html

2. Use it to get a file from your own server program (next). For example, your server is running on 172.18.233.83, port number 10003. java HTTPClient http://172.18.233.83:10003/index.html Note that you can create your own index.html file (doesnt to have a real HTML webpage file) or store any of a downloaded index.html files such as cnn index.html file.

• PUT
  • Use the HTTP client to put data only to your own web server (described next).
  • Your client should accept a three command-line argument: PUT command, URL to where the files should be stored in the server, and the local path/filename of the file to transmit.
  • The URL will be given in the following format:

http://hostname[:port] (only lowercase letters will be used)

• hostname a CS Unix machine (use either atria or sirius)
• :port only ports 10000-11000 are open for use.
• Example: http://172.18.233.83:10010
• The path/name of local file has the format: [path/]<filename>
  • path the path of the location of the file to be transmitted at the current machine ,if this is not present, then the path is /
  • <filename> is the name of the file that you intend to transmit to the server. If doesnt exit, you
• Similarly, if any of the arguments are incorrect, exit after printing an error message of the form ERR arg x, where x is the argument number.
• Connect to the host given in the URL at the port given in the URL thru TCP connection.
  • Handle exceptions as you wish for example, if the file doesnt exist, host doesnt exist, or the port given is not open
• Submit a valid PUT request for path/file to be transferred to the webserver given in the supplied URL using HTTP/1.0.
  • Your request must include the Host field (with the proper entry).
  • Your request must include the Time field (with the proper entry).
  • Your request must also include the User-agent field with the entry VCU-CMSC491.
  • Your request must also include the User-name field with your first name as the entry.
  • No other request fields are needed.
  • Remember to end with extra CR/LF o Print the HTTP PUT request sent to the server.
  • Note: Print the actual string sent to the server. Do not send a request and then re-type the request for output.
• If the server is successful in receiving and storing the file, the server sends back a 200 OK File Created response. Otherwise, the server sends back a 606 FAILED File NOT Created response.
• Parse the HTTP response header received from the server and print the following information:
  • Response code (number)
  • Server type o Print the HTTP response header.

HTTPServer

• Your server should be named HTTPServer.java should or HTTPServer.py
• It must accept a single command-line argument: port, which is the port that it will listen on for incoming HTTP requests.
  • If any of the arguments are incorrect, exit after printing an error message of the form ERR arg x, where x is the argument number.
  • The only error-checking that needs to be done on the port is to ensure it is a positive integer less than 65536.
  • Remember that only ports 10000-11000 are open for use.
• The server should able to handle both HTTP commands: GET and PUT.
• For each new HTTP request, print the clients IP address, port, and the request type in the format IP:port:request

Example: 172.18.233.83:63307:GET

• Print each line in the HTTP request.
• Construct a valid HTTP response including status line, any headers you feel are appropriate, and, of course, the requested file in the response body.
• For GET, If the server receives for example the GET index.html HTTP/1.0 request, o Sends out 200 OK to the client, followed by the file ./index.html. o If the requested file doesnt exist, the server sends out 404 Not Found response to the client.
• For PUT, if the server receives the PUT index.html HTTP/1.0 request, it will save the file as ./index.html.
  • If the received file from client is successfully created, the server sends back a 200 OK File Created response to the client.
  • Otherwise, the server sends back a 606 FAILED File NOT Created response.
• The HTTP server program should remain running until the user closes it with Ctrl-C. The program should close the client socket after each request has been received (even if the browser is using HTTP/1.1), but leave the welcoming/listening socket open.
• Once you have your server working, you could test it with the following two test cases:

1. Use a real browser (e.g., firefox) to GET a file from your server

• Note that you can download an index.html of any site and store in your server for the test.

2. Use your HTTPClient to GET/PUT a file

VM Linux Machines:

• Open terminal window either on Windows, Mac, or Unix machine.
• On terminal, type ssh 172.18.233.83 l <eID> then your VCU password to authenticate. Note that <eID> is your VCU user login.
• To access another machine with different IP, open a new terminal and follow the previous step to connect to the class VM machine (172.18.233.83), and then type ssh 172.16.49.2 -l <eID> using the same set of credentials you used before.

Rules:

• The only programming networking classes allowed are the basic socket classes that weve used with the examples. For example, java.net.URL is not allowed and urllib2 (Python) is not allowed.
• Your code should run on the VM Linux machines (e.g., 172.18.233.83). Remember that only ports 10000-11000 are open for use
• You are not permitted to work with anyone else (even students not in the class) all of the coding and documentation must be your own.
• Your program must compile (if Java/C++) and run on the VM Linux machines.
• You must write neat code and document it well. You will lose points for sloppy programs that contain little or no comments.

Hints:

• Look back in your notes to recall how HTTP requests are formatted and terminated.
• Note that readLine() in Java strips off newline characters before returning a String.
• Use the equals() method in Java to compare two Strings.

Testing:

A large part of your programs grade will be determined by how well it handles a set of inputs. You should test your program rigorously before submitting. Because your programs will be run and tested using a script, you must format your output exactly as I have described or you will lose points.

The examples below are just examples. I will test your programs rigorously. In particular, I will test your HTTP Client on a wide range of URLs.

Example 1 java HTTPServer

Usage: java HTTPServer port

Example 2

In this example, after setting up the server (e.g., on 172.18.233.83), the user

opened a web browser (e.g., on 172.16.49.2) to the URL http://172.18.233.83:10003/my/url

cmsc491> java HTTPServer 10003

172.16.49.2:33083:GET

GET /my/url HTTP/1.1

Host: 172.18.233.83:10003

User-Agent: Mozilla/5.0 (X11; U; SunOS sun4u; en-US; rv:1.7) Gecko/20070606 Accept: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,i mage/png,*/*;q=0.5

Accept-Language: en-us,en;q=0.5

Accept-Encoding: gzip,deflate

Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7

Keep-Alive: 300

Connection: keep-alive

Example 3 java HTTPClient

Usage: java HTTPClient URL or java HTTPClient PUT URL path/<filename>

Example 4 java HTTPClient http://www.egr.vcu.edu/directory/tamer.nadeem/files/foo.txt

GET /directory/tamer.nadeem/files/foo.txt HTTP/1.0

Host: www.egr.vcu.edu