book

Beginning Perl

by Curtis Ovid Poe

September 2012

Beginner

744 pages

15h 48m

English

Wrox

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Perl TodayGetting PerlThe Perl CommunityUsing perldocUsing a Terminal WindowCreating Hello, World!Summary
CPAN and METACPANCPAN ClientsSummary
What is Programming?A Few Things to Note Before Getting StartedScalarsArraysHashesSlicesContextScopeStrict, Warnings, and DiagnosticsPerl’s Built-in VariablesSummary
Using ScalarsArray and List FunctionsBuilt-in Hash FunctionsScoping KeywordsSummary
Using the if Statementfor/foreach loopsUsing while/until LoopsStatement Modifiersgiven/whenSummary
References 101Working with ReferencesSummary
Subroutine SyntaxReturning DataFAIL!Subroutine ReferencesPrototypesRecursionThings to Watch ForSummary

Basic MatchingAdvanced MatchingCommon Regular Expression IssuesSummary
Basic File HandlingDirectoriesUnicodeUseful ModulesSummary
Basic Sortingmap and grepPutting It All TogetherSummary
Namespaces and PackagesSubroutines in Other PackagesBEGIN, UNITCHECK, CHECK, INIT, and ENDPlain Old Documentation (POD)Creating and Installing ModulesSummary
What Are Objects? The Ævar the Personal ShopperThree Rules of Perl OOObjects – Another ViewA Brief RecapGotchasSummary
Understanding Basic Moose SyntaxAdvanced Moose SyntaxMoose Best PracticesSummary
Basic TestsUnderstanding Test::More Test FunctionsUsing Other Testing ModulesUnderstanding xUnit Style Using TestingSummary
A Brief Introduction to HTTPWeb ClientsSummary
Using the DBISelecting Basic DataSummary
The Command LineOther ProgramsSummary
Using CSV DataUnderstanding Basic XMLHandling DatesUnderstanding Your ProgramSummary
What Next?Understanding Object-Relational MappersUsing the Template ToolkitUsing Catalyst to Build AppsSummary

Content preview from Beginning Perl

Chapter 15 The Interwebs

WHAT YOU WILL LEARN IN THIS CHAPTER:

Understanding the basics of the HTTP, including web servers, web forms, cookies and security issues
Understanding a web client’s role

WROX.COM CODE DOWNLOAD FOR THIS CHAPTER

The wrox.com code downloads for this chapter are found at http://www.wrox.com/remtitle.cgi?isbn=1118013847 on the Download Code tab. The code for this chapter is divided into the following major examples:

app.psgi and anne_frank_stamp.jpg
character.psgi
example_15_1_google_directions.pl
listing_15_1_get_links.pl
listing_15_2_get_comments.pl
listing_15_3_post_character.pl
params.psgi
templates/character.tt
templates/character_display.tt

Ah, Perl, the duct tape of the Internet. Duct tape has a reputation for being an amazing, ad hoc supertool for fixing things in a hurry, even as a combat dressing. Perl is the same way. Need something done on the web quickly? Reach for Perl!

This chapter pays particular attention to the HyperText Transfer Protocol (HTTP). When you view a web page in your browser, it was probably sent to you via HTTP (or HTTPS, the encrypted version of HTTP). HTTP is nothing more than text, and Perl excels at text manipulation. Your author believes you need a foundation of how HTTP flows between systems to effectively program at a higher level.

The first part of this chapter is about responding as a server. It will not be “Here’s how to write a web application”; though you create some simple ones, but rather, “Here are some concepts ...