CGI programming Using Apache

Concepts Browser prepares parameter list List is attached to name of program to run on server "submit" button sends string to server as name/value pairs Server locates program in CGI directory Server loads program Server passes string to program Program processes parameters and acts as needed Program creates strings and outputs to server One line of HTML code per output statement (cout, printf, etc) ALL stream output goes to the Server Server sends strings to browser Browser interprets the HTML code & displays the "page"

CGI output (C++ example) #include cout << "Content-Type: text/html\n\n" << endl; cout " << endl; // HTML 5 cout " << endl; …. Your HTML & text go here … cout " << endl; 1 st line identifies output media type to browser 2 nd line identifies document type version 3 rd line is actual start of the page

Content-type problems Inability of data source to identify content Wrong file extension Bad file extension Extension collisions Ambiguous container formats Ambiguous magic numbers Inability of receiver to trust sender's media type Programmers try to guess content type by examination

Using styles Output is a stream representing a single "file" HTML files do NOT have to have one tag per line Output can be individual lines or several long lines: cout text item1 "<<endl; Styles can be embedded or inline Generate style tags just like any other HTML cout.red {font:red} " << endl; cout << ".bigtext {text-size:150%} " << endl; " << endl;

Using JavaScript JS can be inserted: as functions in As inline code inside in body of doc CGI generated pages "act like" real pages

Activating your CGI program Generate an HTML form (using cout or printf): … {your JS function def's and html and go here} document.myform.submit(); // this submits the form to the browser Where I have "chkflds" you could put the name of a function to validate the fields The function would have to be inside and tags RECOMMENDATION: put the form's elements inside a table.. Input/button tags here…

Setting up your Apache server Open terminal window Type: nano /etc/httpd/conf/httpd.conf (or use your favorite editor instead of nano) Locate "ServerAdmin" and replace the address with yours Locate "ServerName" and replace the default with your TJWnnn account (tjwnnn.cc.binghamton.edu) Save the file using the same name it had In the terminal window type the following command: apachectl start Close your session

Testing your web server Create a simple web page Save it in /var/www/html with the name: index.html Open a browser on your own PC (NOT on the TJW machine) Enter the address of your tjw account e.g.; tjw241.cc.binghamton.edu (that's mine!!) You should now see your test page