There are many examples the reader can cut and paste into his/her programming environment and experiment with.Of the multitude of Perl features, this page concentrates on those likely to be of use for the beginning CGI programmer.Input validation is important to prevent SQL injection and Cross Site Scripting (XSS) attacks, and also to make sure your -for example- database contains only valid data.Here you see two Perl code snippets to use for input validation.Validate an email address and ZIP code syntax with Perl regular expressions; how to validate user input to prevent SQL injection and Cross Site Scripting in Perl, and make sure your database contains only valid data.These examples use Perl regular expressions to validate postal codes and email addresses.", so that the next command prompt appears on its own line.If you use two "\n" sequences you will create a blank line between the line containing "Hello world! Each newline character forces the writing cursor to drop down one line.
Consider this HTML form from the application which creates a new user: The Dancer2 route that handles it looks as simple as this: Once the form is submitted, HTML:: Form Handler processes the parameters from Dancer2.
\d doesn't validate numbers, unless you have already verified that your input contains only ASCII characters.
What \d does is to validate whether a number is regarded as a numeral in Unicode.
Unicode:: UCD::num(), since Perl 5.14, can be used to make sure that a string of digits are all from the same script, so are not spoofing attempts, returning the numeric value the string represents, or undef if it is illegal. As a followup to this article, I am thinking about making another blog post showing how \d is used to match numbers in actual CPAN modules. q=\d\+\..*/[b-z]*a Noting your comment, I tried searching for CPAN modules which use the /a flag to restrict \d so that it only matches ASCII digits.
A few days ago I pushed to Git Hub a sample web application written in the MVC style with Dancer2 and DBIx:: Class.