1. MANAGE YOUR DATA
FROM A B-BOY STANCE
John SJ Anderson / @genehack
dc.pm / 2012-05-01

2. MAD PROPS
Cory Watson (GPHAT)
Jay Shirley (JSHIRLEY)

3. DATA::MANAGER IS

4. DATA::MANAGER IS
Input Validation

5. DATA::MANAGER IS
Input Validation
Error Handling

6. DATA::MANAGER IS
Input Validation
Error Handling
Message Passing

7. DATA::MANAGER IS
Input Validation
Error Handling
Message Passing
“Opinionated Software”

8. DATA::MANAGER ISN’T

9. DATA::MANAGER ISN’T
Form Generation

10. DATA::MANAGER ISN’T
Form Generation
Form Rendering

11. DATA::MANAGER ISN’T
Form Generation
Form Rendering
Right For Everybody

12. DATA::MANAGER IS

13. DATA::MANAGER IS
1 or more Data::Verifier
objects

14. DATA::MANAGER IS
1 or more Data::Verifier
objects
1 Message::Stack object

15. DATA::MANAGER IS
1 or more Data::Verifier
objects
1 Message::Stack object
Tiny bit of sugar code
sprinkled over the top

16. TASK:
ACCOUNT CREATION FORM
Username field (text box)
Password field (password box)
“Password again” field (password box)

17. TASK:
ACCOUNT CREATION FORM
Constraints:
username must be
populated
password must be >4
characters long
password must be the
same as password2

18. TEST CASES

19. TEST CASES
Pass case: everything filled in properly

20. TEST CASES
Pass case: everything filled in properly
Fail cases:
No username
No password
No password2
Short password
Value of password != password2

21. TEST CODE
A/K/A
ILL-ADVISED LIVE DEMO

22. DATA::VALIDATOR CODE
A/K/A
MORE ILL-ADVISED LIVE DEMO

23. WEB CONTEXT

24. WEB CONTEXT
So now we understand how
to take a set of fields and
validate them

25. WEB CONTEXT
So now we understand how
to take a set of fields and
validate them
But in a web/CGI context,
if the validation fails, we
can’t just die();

26. WEB CONTEXT
So now we understand how
to take a set of fields and
validate them
But in a web/CGI context,
if the validation fails, we
can’t just die();
Have to communicate nature
of failure back to the user

27. WEB CONTEXT

28. WEB CONTEXT
Also, in a more realistic case, we’ll have more complicated
forms

29. WEB CONTEXT
Also, in a more realistic case, we’ll have more complicated
forms
1 form submit -> changes to multiple objects / tables on the
backend

30. WEB CONTEXT
Also, in a more realistic case, we’ll have more complicated
forms
1 form submit -> changes to multiple objects / tables on the
backend
From a UI perspective, we want to display error messages as
close to the source as possible

31. DATA::MANAGER IS

32. DATA::MANAGER IS
1 or more Data::Verifier objects

33. DATA::MANAGER IS
1 or more Data::Verifier objects
1 Message::Stack object

34. DATA::MANAGER IS
1 or more Data::Verifier objects
1 Message::Stack object
1 Data::Verifier per form “scope”

35. DATA::MANAGER IS
1 or more Data::Verifier objects
1 Message::Stack object
1 Data::Verifier per form “scope”
1 Message::Stack object to contain all errors/messages about
the results of verifying all the Data::Verifiers in the
Data::Manager

36. DATA::MANAGER IS
1 or more Data::Verifier objects
1 Message::Stack object
1 Data::Verifier per form “scope”
1 Message::Stack object to contain all errors/messages about
the results of verifying all the Data::Verifiers in the
Data::Manager
Tiny bit of sugar code sprinkled over the top

37. NO FORM GENERATION
how does that work?

38. TEMPLATE MACROS
A/K/A MEANS NOW, RIGHT?
EVERYBODY KNOWS WHAT THIS SLIDE

39. PUT IT ALL TOGETHER
what do you get?

40. THANKS!
Questions?

41. MORE INFOZ
https://metacpan.org/module/Data::Manager
https://metacpan.org/module/Data::Verifier
https://metacpan.org/module/Message::Stack
http://www.slideshare.net/jshirley/building-better-
applications-with-datamanager