CMPS-3350 Software Lab-3

Step 1:

Log on to your Odin account.

Change to your 3350/3 folder.

Copy the files to start with for this lab...

cp /home/fac/gordon/p/3350/code/lab3/* .

Build the program with make.

You should see a compile warning.

gordon@odin:~/3350/3$ make
gcc httpget.c -Wall -o lab3
httpget.c: In function 'main':
httpget.c:127:3: warning: implicit declaration of function 'close';
                    did you mean 'pclose'? [-Wimplicit-function-declaration]
  127 |   close(sock);
      |   ^~~~~
      |   pclose
gordon@odin:~/3350/3$

Step 3:

You are refactoring a C program into the C++ language.

Refactoring means to modify source code without changing program functionality.

Build your C++ program with make.

Notice the warnings and errors when compiling your C++.


gordon@odin:~/3350/3$ cp httpget.c uvlab3.cpp

gordon@odin:~/3350/3$ g++ uvlab3.cpp -Wall

uvlab3.cpp: In function 'int main(int, char**)':
uvlab3.cpp:35:14: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]
   35 | #define PAGE "/"
      |              ^~~
uvlab3.cpp:58:12: note: in expansion of macro 'PAGE'
   58 |     page = PAGE;
      |            ^~~~
uvlab3.cpp:86:14: warning: comparison of integer expressions of different
    signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare]
   86 |   while(sent < strlen(get))
      |         ~~~~~^~~~~~~~~~~~~
uvlab3.cpp:127:3: error: 'close' was not declared in this scope; did you mean 'pclose'?
  127 |   close(sock);
      |   ^~~~~
      |   pclose
uvlab3.cpp: In function 'char* build_get_query(char*, char*)':
uvlab3.cpp:170:15: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]
  170 |   char *tpl = "GET /%s HTTP/1.0\r\nHost: %s\r\nUser-Agent: %s\r\n\r\n";
      |               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

gordon@odin:~/3350/3$

Step 4:

Please fix all compile warnings and errors.

Enter a comment above the code related to each error or warning that you fix.
Include the original code that was fixed, in the comment.

For example:

//---------------------------------------------------------------------
//Fixed warning: deprecated conversion from string constant to 'char*'
//Previous code was:
//   void getHost(char *hostname)
//---------------------------------------------------------------------
void getHost(const char *hostname)
{
    ...
    ...
    ...



Step 4a:

 . Style this program using the Linux style guide.

  Main features...

   . Apply perfect K&R brace, space, and indenting.
   . No lines will wrap on an 80-character window.
   . Choose hard-tabs or spaces for indenting. Not both.
   . One command per LOC (line of code)
   . Fix all compile warnings and errors.




Step 4 note:
It is acceptable to fix a compile warning by using type-casting.
Such as casting a function call argument.

Step 5:

Run your lab3 program with the following parameters...

www.google.com
robots.txt

example:
./lab3 www.google.com robots.txt

What you should see is a list of restrictions posted by the owner of the website you are accessing.


As you can see, accessing a website using automated means is restricted.
When using your HTTP program, always check the robots.txt file, and
follow the instructions for that site.

Step 6a:

Run lab3 with the following parameters...

odin.cs.csub.edu
robots.txt

You should see an error!

Try accessing the Odin server using curl.

curl odin.cs.csub.edu/robots.txt

Another error, so do this...

curl https://odin.cs.csub.edu/robots.txt

Now we got it.

Step 7:

Create a PHP program in your Odin public_html directory...
It will have this URL:

	https://cs.csub.edu/~username/3350/uvlab3.php

where username is your own Odin account name.

If you have any questions about the path to your uvlab3.php, please ask
about it during lab.


Here is a PHP program example...


<?php
echo "This is output from my php file.";
?>

Step 8:

Run your lab3 program and contact your PHP file.

like this... except insert your own username

    ./lab3  odin.cs.csub.edu  /~username/3350/uvlab3.php

This operation will not work because Odin server is running HTTPS.

To simulate our program, we will use the curl utility.

Try this: curl https://odin.cs.csub.edu/~username/3350/uvlab3.php

Step 9:

Use a web browser to look at your php file

    like this...

    https://www.cs.csub.edu/~username/3350/uvlab3.php

Step 10:

Make some minor changes to your uvlab3.php program...

Allow the program to accept input:
	$param = $_GET['param'];

Process the $param variable in the PHP file.

Your new PHP program will look like this...


<?php
$param = $_GET['param'];
echo "param is: " . $param . "<br>";
if ($param == "hello") {
    echo "Hello student!<br>";
} else {
    $num = $param*3+4;
    echo "number:" . $num . "<br>";
}
echo "<br>";
echo "<img src=\"uvdiagram.gif\"/>";
?>


Required:
 1. Create a file named uvdiagram.gif for your diagram below.

    For image file conversion...

       You may use GIMP for file conversion.

       You may also use convert from the Odin command-prompt.

		   example: $ convert image.jpg uvdiagram.gif

       Inside your <img> tag, apply a style element that will
       size your diagram to an appropriate size.

		   example: style="width:800px;height:auto;"

       The <img> tag is in your php file.

Step 11:

Contact and test your PHP file like this...

curl odin.cs.csub.edu/~username/3350/uvlab3.php?param=hello

Then try this...

curl odin.cs.csub.edu/~myname/3350/uvlab3.php?param=345

You should see the appropriate data returned.

Step 12:

Draw a Diagram!

Draw a Diagram to show the components of your system, and how they interact with each other. Think about the flow of data through the system. How would a user interact with the system?

. Create an original diagram.
. Create a nice diagram please.

Free online drawing tools: draw.io Gliffy

Note, this diagram will be viewed by your instructor and by the class.
Also, contacting your php file will display your diagram.

Your diagram may be a
   flow-chart
   data-flow-diagram
   use-case diagram
   etc.