Producing robust programs

Producing robust programs

1. Validation

   • Checking data to make sure it is reasonable
   • Range check
     • An age should be in a specific range
   • Format check
     • E-mail addresses should follow a specific format. (Regular expression)
   • Presence check
     • Checking to make sure data has been entered.
   • Type check
     • Checking to see if the data entered is a specific type, for example, checking if a number has been entered.

2. Authentication

   • Ensuring that someone is who they say they are.
   • Password
   • PIN number
   • Secret question
   • Physical object
     • Swipe card, biometrics, ...

3. Maintainability

   • Ensuring that the code is readable and maintainable
   • Comments
     • Used to label what a part of the code does. For example: '// this is a loop'
   • Sensible variable names
     • Making sure variable names make sense. For example, 'userName' is a better than 'x'
   • Indentation
     • Using indentation to show separate blocks of code. (see example in the note)
       • // Example Java code for(int i = 0; i < 10; i++) {       System.out.println("The number is: " + i); }

4. Sanitization

   • Removes any potentially malicious data from an input.
   • Input sanitization is a (poor) method of preventing SQL Injection. By removing SQL queries from an input, you can mitigate SQL Injection.