Description

DATA COMMUNICATIONS AND COMPUTER NETWORKS
LABWORK 1 – SECTION 2

Below, you can find the description of your labwork for today. You are required to develop a Java application to save image files from a web server and check if it is modified or not. In order to do so, you will use the given HTMLTest class and modify the code.
For the part 1, in the given HTMLTest class, you are required to extract the payload image file and save it as image.jpg.
Note: Before testing your program, you should download the zero tier from https://www.zerotier.com/. When you run the installed program, choose Join network and type 12ac4a1e71d65a30 to related field.
Online participants should use the below URL when testing their application:
http://172.30.122.241:8080/3dsk4fsljnw4.jpg
In-class users should use the below URL when testing their application:
http://10.2.10.202:8080/3dsk4fsljnw4.jpg

Application Walkthrough
Please Enter the URL address of the web page: http://172.30.122.241:8080/3dsk4fsljnw4.jpg
GET /3dsk4fsljnw4.jpg HTTP/1.1
Host: 172.30.122.241
Connection: close

HTTP message for if-modified-since:
GET /3dsk4fsljnw4.jpg HTTP/1.1
Host: 172.30.122.241
Connection: close

Received header:
HTTP/1.1 304 Not Modified
Server: Apache/2.4.38 (Debian)
Connection: close
ETag: “2e017-593ece6508b67”