PERL/C3/Perl-and-HTML/English-timed

'Time	Narration
00:01	Welcome to the Spoken Tutorial on Perl and HTML.
00:06	In this tutorial, we will learn how to create html pages and CGI module.
00:14	To record this tutorial, I am using: Ubuntu Linux 12.04 operating system Perl 5.14.2 Firefox Web Browser Apache HTTP server and 'gedit' Text Editor.
00:31	You can use any text editor of your choice.
00:35	To follow this tutorial, you should have working knowledge of Perl programming.
00:40	If not, then go through the relevant Perl spoken tutorials on the spoken tutorial website.
00:47	Perl programs which are used on the web are called Perl CGI.
00:52	CGI stands for Common Gateway Interface.
00:56	It is an interface to serve client-server web communication.
01:01	CGI.pm is a Perl module that gets installed along with Perl installation which serves the communication.
01:10	CGI.pm has ready to use functions to help developers, to write Perl CGI applications.
01:19	When a file in certain directory is requested from web browser, unlike HTTP server, Perl CGI scripts get executed and send output back to browser to display.
01:33	This function is called CGI and the programs are called CGI scripts.
01:40	CGI programs can be a Perl script, Shell Script, C or C++ program.
01:47	Now, let us see a sample Perl program.
01:50	Switch to the terminal.
01:53	Let me open a file cgiexample.pl in gedit which I have already saved.
02:01	In the cgiexample dot pl file, type the following code as displayed on the screen.
02:08	Let us understand the code now.
02:11	use CGI statement tells Perl that we want to use the CGI.pm module in our program.
02:19	It will load the module and make a set of CGI functions available for our code.
02:26	To start the HTML, we use the method start_html().
02:33	“My Home Page” is the page title given for the web page.
02:38	We can print any HTML tag using the CGI module.
02:43	Heading tags are represented by h1, h2 etc.
02:49	The end_html method returns the BODY and HTML tags.
02:55	Now, save the file.
02:57	Before we try to run the script via the web server, let's try running it from the command line.
03:04	Switch back to the terminal and type: perl cgiexample.pl and press Enter.
03:12	The output looks like HTML.
03:15	Next, we will test the same script via the web server.
03:20	First, let us check whether web server is working or not.
03:25	Open your web browser and enter the IP address of the machine and press Enter.
03:31	Otherwise, you can type as "localhost".
03:35	If everything works fine, you will see something like this in the browser.
03:40	If you get any error, then the web service is not installed or it is not in ON status.
03:48	Apache HTTP server is installed in my machine.
03:52	If it is not installed, execute the below command on the terminal.
03:58	Otherwise, please ask your system administrator for server configuration.
04:04	Now, we will test the same script via the web server.
04:09	For this, we need to follow certain steps.
04:13	First place our program in the cgi-bin directory where the web server will recognize it as a CGI script.
04:22	The program filename must end with dot pl or dot cgi extension.
04:29	Set permission for the file to execute on the server.
04:33	Run the script.
04:35	The URL for this program will be as shown in the slide.
04:40	Switch to the terminal.
04:42	Now, we will copy the file to the cgi-bin directory.
04:47	For this, type the command: sudo space cp space cgiexample.pl /usr/lib/cgi-bin/.
05:03	Enter the password if required.
05:06	Next, we need to give the Web-server user 'read' and 'execute' permission for the file.
05:13	For this, type: sudo space chmod space 755 space /usr/lib/cgi-bin/cgiexample.pl
05:31	Now our file which is placed in the cgi-bin directory is ready to execute.
05:38	Go to the web browser.
05:41	Type: localhost/cgi-bin/cgiexample.pl and press Enter.
05:50	We can see the output that is executed on the web browser.
05:55	Now, let us see another program. This program will add fields to a form and retrieve the entered values to our web page.
06:06	In the cgi-bin directory created earlier, I have saved a file form.cgi. I will open this file in gedit.
06:17	Now, add the below lines. This program generates a feedback form.
06:24	The user has to enter the first name, last name, gender and feedback details.
06:31	To begin a form, we are using start_form() method.
06:36	Form field methods are very similar to the standard html tag methods.
06:42	To create a textbox in the form, Textfield method is used with several parameters.
06:49	Here “fname”, “lname” are the names of the textbox which get the input from the user.
06:57	radio underscore group specifies the radio button with two options “Male” and “Female”.
07:05	This is denoted by the parameter hyphen values.
07:09	hyphen default parameter indicates the default selection of the radio button.
07:15	popup underscore menu specifies the listbox option.
07:20	Submit button is used to submit the entered data to the URL provider.
07:26	Clear button is used to clear the form.
07:30	The displayform function retrieves the values, we entered in the form.
07:36	param() function gives the value of the form field whose name is passed as parameter.
07:42	Here “fname” is the name given to the “First Name” textbox.
07:47	The value is retrieved and stored in the variable dollar name1.
07:53	Let us execute the program now.
07:56	Go to the web browser.
07:58	Type: localhost/cgi-bin/form.cgi and press Enter.
08:06	The feedback form is displayed.
08:09	I'll enter data in this form as shown here.
08:15	Then, press the Submit button to see the output that is retrieved from the form.
08:21	This brings us to the end of this tutorial. Let us summarize.
08:26	In this tutorial, we learnt how to create html pages using CGI module.
08:33	Assignment- In form.cgi program, add checkbox option for languages Java, C/C++ and Perl.
08:44	Add textarea option to get the user feedback.
08:48	Print the user entered information on the webpage.
08:52	The video at the following link summarises the Spoken Tutorial project. Please download and watch it.
08:59	The Spoken Tutorial Project Team: conducts workshops using spoken tutorials and gives certificates on passing online tests.
09:08	For more details, please write to us.
09:11	Spoken Tutorial project is funded by NMEICT, MHRD, Government of India. More information on this mission is available at this link.
09:23	This is Nirmala Venkat from IIT Bombay, signing off. Thanks for watching.

Contributors and Content Editors

PoojaMoolya, Sandhya.np14