Inhaltsverzeichnis

Networking

30.10.2014

SocketTest from Akshathkumar Shetty

http://sockettest.sourceforge.net/

It's a simple Java Tool for testing any TCP or UDP Client/Server applications or services, which are based on text-data-transfer.

Fiddler Web Debugger

31.10.2014
http://www.telerik.com/fiddler
Seems to be a quite useful tool for having a look on the web traffic.

HTTP GET vs. POST

1.11.2014
Let's have a look at this simple HTML code: 

<html><body>
<h3>Leave a comment:</h3>
<form name="formExample1" action="http://localhost:8080/process.php" method="post">
Name: <br> <input type="text" name="name" value="Jon Doe"> <br>
Rating: <br>
<input type="radio" name="rating" value="1" > 1
<input type="radio" name="rating" value="2" checked="true"> 2
<input type="radio" name="rating" value="3"> 3 <br>
Comment: <br> <textarea name="comment">enter comments here ...</textarea> <br><br>
<input type="submit" value="Submit Comment">
</form>
</body></html>

It looks like this in the browser:

I set up a local TCP-server with SocketTest on port 8080. I open the html-file above in my browser, and click submit. What the server receives is: 

POST /process.php HTTP/1.1
Host: localhost:8080
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:29.0) Gecko/20100101 Firefox/29.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Connection: keep-alive
Content-Type: application/x-www-form-urlencoded
Content-Length: 53

name=Jon+Doe&rating=2&comment=enter+comments+here+...

As we see, we get all the input-fields (name-value-pairs), which are defined in the form. The data is transmitted in the HTTP-message-body. This is, because we used the method=„post“.
When we use method=„get“, the server receives folloing message: 

GET /process.php?name=Jon+Doe&rating=2&comment=enter+comments+here+... HTTP/1.1
Host: localhost:8080
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:29.0) Gecko/20100101 Firefox/29.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Connection: keep-alive

As we can see now, all the name-value-pairs are transmitted in the HTTP-message-header, and the message has no body.

A HTTP request header ends with an empty line. The new line characters are <CR><LF>, as used in the Windows-world.

nmap

check accessible ports on a computer in the network or on the internet: 

nmap -A zeilhofer.co.at

Learning HTML

http://www.simplehtmlguide.com
Youtube: Learn HTML in 12 Minutes
Youtube: Learn more HTML in 12 Minuts HTML, XHTML and HTML5 Cheat Sheet as a PDF

Learning PHP

I have created a printable version of „PHP Programming“ on wikibooks.org
https://en.wikibooks.org/wiki/Wikibooks:Collections/PHP_Programming

Here are links to my first PHP files:
http://www.zeilhofer.co.at/php_learning/helloworld.php

helloworld.php
<?php
 
echo "Hello World!<br>";
 
?>

http://www.zeilhofer.co.at/php_learning/myfirstphpfile.php?relay1=5&relay2=7

myfirstphpfile.php
<?php
 
echo "Hello World!<br>";
 
// print unix time stamp (in seconds)
// append strings with dot
echo "unix time = ".time()."s<br>"; 
 
// receive arguments form the url (webrequest):
 
// declare variables:
$relay1 = $_REQUEST['relay1'];
$relay2 = $_REQUEST['relay2'];
 
echo "relay1 = $relay1 and relay2 = $relay2";
?>

php.ini

diff /etc/php5/apache2/php.ini /usr/share/doc/php5-common/examples/php.ini-development

If this command returns nothing, then your PHP uses dev configuration. 

diff /etc/php5/apache2/php.ini /usr/share/php5/php.ini-production

If this command returns nothing your PHP uses production configuration.

If you want to use dev configuration, 

sudo cp /usr/share/doc/php5-common/examples/php.ini-development /etc/php5/apache2/php.ini

If you want to use production configuration, 

sudo cp /usr/share/php5/php.ini-production /etc/php5/apache2/php.ini
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