ݺߣ

ݺߣShare a Scribd company logo

Web Development Paradigms and djangoic approach to deal with them

?
?
Lakshman Prasad
Lakshman Prasad

The document discusses various web development paradigms and Django's approach to dealing with them. It covers concepts like forms, authentication, generic views, caching and the Django admin. The summary provides an overview of the key topics covered in the document.

1 of 49
Downloaded 13 times
Introduction Forms Authentication Generic Views Caching Others Admin Web Development Paradigms and djangoic approach to deal with them. Lakshman Prasad Agiliq Solutions September 25, 2010
Concepts and abstractions used to represent elements of a program
Web Development Paradigms: Modeling common web patterns
Why?
Web Development Paradigms and djangoic approach to deal with them
Batteries Included
docs.djangoproject.com
Webapp: Simple web application framework (with custom APIs)
Lets examine the batteries
Introduction Forms Authentication Generic Views Caching Others Admin How do I know about web development or django ? Active Djangonaut ? Part of a few popular open source django applications github.com/becomingGuru, github.com/agiliq ? Consulting and Development via ? Developed several custom proprietory django applications ? @becomingGuru
Introduction Forms Authentication Generic Views Caching Others Admin Introduction Forms Authentication Generic Views Caching Others Admin
Forms
Save form data to a table
Introduction Forms Authentication Generic Views Caching Others Admin Use a Model Form >>> from d j a n g o . f o r m s import ModelForm # C r e a t e t h e form c l a s s . >>> c l a s s A r t i c l e F o r m ( ModelForm ) : ... c l a s s Meta : ... model = A r t i c l e # C r e a t i n g a form t o add an a r t i c l e . >>> form = A r t i c l e F o r m ( ) # C r e a t i n g a form t o c h an ge an e x i s t i n g a r t i c l e . >>> a r t i c l e = A r t i c l e . o b j e c t s . g e t ( pk=1) >>> form = A r t i c l e F o r m ( i n s t a n c e= a r t i c l e )
Models
Introduction Forms Authentication Generic Views Caching Others Admin Model Syntax from d j a n g o . db import m o d e l s c l a s s P o s t ( m o d e l s . Model ) : t i t l e = m o d e l s . C h a r F i e l d ( m a x l e n g t h =100) t e x t = models . T e x t F i e l d ( ) datetime = models . DateTimeField ( ) c l a s s Meta : o r d e r i n g = ( ?d a t e t i m e , ) def unicode ( self ): return s e l f . t i t l e c l a s s Comment ( m o d e l s . Model ) : post = models . ForeignKey ( Post ) t e x t = models . T e x t F i e l d ( )
Introduction Forms Authentication Generic Views Caching Others Admin Model API >>>from b l o g . m o d e l s import Post , Comment >>>p o s t = P o s t . o b j e c t s . a l l ( ) [ 0 ] >>>p o s t c o m m e n t s = p o s t . c om m en t s et . a l l ( )
Introduction Forms Authentication Generic Views Caching Others Admin Save Foreign Keys
Introduction Forms Authentication Generic Views Caching Others Admin Use Model Formset from d j a n g o . f o r m s . m o d e l s import m o d e l f o r m s e t f a c t o r y AuthorFormSet = m o d e l f o r m s e t f a c t o r y ( Au t ho r ) f o r m s e t = AuthorFormSet ( ) >>> p r i n t f o r m s e t <i n p u t t y p e= h i d d e n name= form?TOTAL FORMS v a l u e= 1 i d= i d f o r m ?TOTAL FORMS /> <i n p u t t y p e= h i d d e n name= form?INITIAL FORMS v a l u e= 0 i d= i d f o r m ?INITIAL FORMS /> <i n p u t t y p e= h i d d e n name= form?MAX NUM FORMS i d= i d f o r m ?MAX NUM FORMS /> <t r ><th> < l a b e l f o r= i d f o r m ?0?name>Name:</ l a b e l > </th><td> <i n p u t i d= i d f o r m ?0?name t y p e= t e x t name= form ?0?name m a x l e n g t h= 100 /> </td ></t r >
Introduction Forms Authentication Generic Views Caching Others Admin Model Formset options f o r m s e t = AuthorFormSet ( q s=Au th o r . o b j e c t s . a l l ( ) , e x t r a =5) formset . i s v a l i d () formset . e r r o r s { name : T h i s f i e l d is required } formset . changed forms formset . save ()
Introduction Forms Authentication Generic Views Caching Others Admin Form pre populated
Introduction Forms Authentication Generic Views Caching Others Admin Forms dont have to save to a Model from d j a n g o import f o r m s c l a s s ContactForm ( f o r m s . Form ) : s u b j e c t = f o r m s . C h a r F i e l d ( m a x l e n g t h =100) message = f o r m s . C h a r F i e l d ( ) sender = forms . E m a i l F i e l d () c c m y s e l f = f o r m s . B o o l e a n F i e l d ( r e q u i r e d=F a l s e ) def s a v e ( s e l f ) : #Do a n y t h i n g ...
Form Preview
Introduction Forms Authentication Generic Views Caching Others Admin Form Preview from d j a n g o . c o n t r i b . f o r m t o o l s . p r e v i e w import FormPreview from myapp . m o d e l s import SomeModel #Add a u r l ( r ? p o s t / $ , SomeModelFormPreview ( SomeModelForm ) ) , #D e f i n e form p r e v i e w c l a s s SomeModelFormPreview ( FormPreview ) : def done ( s e l f , r e q u e s t , c l e a n e d d a t a ) : # Do s o m e t h i n g w i t h t h e c l e a n e d d a t a , t h e n # r e d i r e c t t o a s u c c e s s page . r e t u r n H t t p R e s p o n s e R e d i r e c t ( / form / s u c c e s s )
Form Wizard
Introduction Forms Authentication Generic Views Caching Others Admin Form Wizard c l a s s C o n t a c t W i z a r d ( FormWizard ) : def done ( s e l f , r e q u e s t , f o r m l i s t ) : do something with the form data ( fo r m l is t ) return HttpResponseRedirect ( / r e d i r e c t / )
Authentication
Introduction Forms Authentication Generic Views Caching Others Admin Point to url pattern u r l p a t t e r n s += p a t t e r n s ( d j a n g o . c o n t r i b . a u t h . v i e w s , u r l ( r ? l o g i n /$ , l o g i n ) , u r l ( r ? l o g o u t /$ , l o g o u t ) , u r l ( r ? r e g i s t e r /$ , r e g i s t e r ) , u r l ( r ? p a s s r e s e t /$ , p a s s w o r d r e s e t ) , u r l ( r ? p a s s r e s e t 2 /$ , p a s s w o r d r e s e t d o n e ) , u r l ( r ? p a s s r e s e t c o n f i r m / ( ?P<u i d b 3 6 >[?w]+)/ , password reset confirm ) , u r l ( r ? p a s s r e s e t c o m p l e t e /$ , password reset complete ) , )
Introduction Forms Authentication Generic Views Caching Others Admin Login Required from d j a n g o . c o n t r i b . a u t h . d e c o r a t o r s import login required @ l o g i n r e q u i r e d ( r e d i r e c t f i e l d n a m e= r e d i r e c t t o ) def my view ( r e q u e s t ) : ...
Introduction Forms Authentication Generic Views Caching Others Admin Authentication backends class SettingsBackend : A u t h e n t i c a t e a g a i n s t t h e s e t t i n g s ADMIN LOGIN and ADMIN PASSWORD . def a u t h e n t i c a t e ( s e l f , username=None , p a s s w o r d=None ) i f l o g i n v a l i d and p w d v a l i d : return user r e t u r n None def g e t u s e r ( s e l f , u s e r i d ) : try : r e t u r n U s e r . o b j e c t s . g e t ( pk=u s e r i d ) except U s e r . D o e s N o t E x i s t : r e t u r n None
django-socialauth
Send to template
Introduction Forms Authentication Generic Views Caching Others Admin Generic Views from d j a n g o . c o n f . u r l s . d e f a u l t s import ? from d j a n g o . v i e w s . g e n e r i c . s i m p l e import d i r e c t t o t e m p l a t e urlpatterns = patterns ( , ( ? about /$ , d i r e c t t o t e m p l a t e , { t e m p l a t e : a b o u t . html }) )
Introduction Forms Authentication Generic Views Caching Others Admin Object based generic views
Introduction Forms Authentication Generic Views Caching Others Admin Display objects and their lists from d j a n g o . v i e w s . g e n e r i c . l i s t d e t a i l import object detail , object list u r l ( ( r ? o b j e c t s / page ( ? P<page >[0 ?9]+)/ $ , object list , dict ( info dict )) , ( r ? o b j e c t s / ( ?P<i d >[0 ?9]+)/ $ , object detail , dict ( info dict )) , )
Introduction Forms Authentication Generic Views Caching Others Admin List of generic views django . views . g e n e r i c . simple . d i r e c t t o t e m p l a t e django . views . g e n e r i c . simple . r e d i r e c t t o django . views . g e n e r i c . l i s t d e t a i l . o b j e c t l i s t django . views . g e n e r i c . l i s t d e t a i l . o b j e c t d e t a i l django . views . g e n e r i c . create update . c r e a t e o b j e c t django . views . g e n e r i c . create update . update object django . views . g e n e r i c . create update . d e l e t e o b j e c t
Normalized data is for sissies - Cal Henderson
Introduction Forms Authentication Generic Views Caching Others Admin Di?erent blocks need di?erent caching durations
Introduction Forms Authentication Generic Views Caching Others Admin Generally Memcache Every page CACHE BACKEND = memcached : / / 1 2 7 . 0 . 0 . 1 : 1 1 2 1 1 / CACHE BACKEND = memcached : / / 1 7 2 . 1 9 . 2 6 . 2 4 0 : 1 1 2 1 1 ; 172.19.26.242:11212;172.19.26.244:11213/
Introduction Forms Authentication Generic Views Caching Others Admin Implement a caching decorator from d j a n g o . c o r e . c a c h e import c a c h e def c a c h e f o r ( s e c o n d s , f e t c h =0): def c a c h e i t ( f u n c ) : def d e c o f u n c ( s e l f ) : v a l = cache . get ( s e l f . g e t c a c h e k e y ( f e t c h )) i f not v a l : val = func ( s e l f ) cache . s e t ( s e l f . g e t c a c h e k e y ( f e t c h ) , val , seconds ) return v a l return deco func return c a c h e i t
Introduction Forms Authentication Generic Views Caching Others Admin Apply on the blocks class TwitterBlock ( TwitterSearchBlock ) : t e m p l a t e n a m e = t w i t t e r u s e r b l o c k . html a j a x t e m p l a t e = t w e e t s u s e r . html @ c a c h e f o r ( 6 0 ? 6 0 , f e t c h =1) def f e t c h d a t a ( s e l f ) : tw = T w i t t e r ( e m a i l= umoja com ) u s e r t w e e t s = tw . s t a t u s e s . u s e r t i m e l i n e ( s c r e e n n a m e= s e l f . d a t a ) r e t u r n u s e r t w e e t s , None
Introduction Forms Authentication Generic Views Caching Others Admin Di?erent cache Backends ? Database ? File System ? Local Memory ? Dummy- For Development
Introduction Forms Authentication Generic Views Caching Others Admin More Paradigms ? Internationalization ? Localization ? Humanization ? CSRF Protection ? Pagination ? Sorting ? Data grid ? Sorl Thumbnail
Web Development Paradigms and djangoic approach to deal with them
Introduction Forms Authentication Generic Views Caching Others Admin Admin by models alone
Introduction Forms Authentication Generic Views Caching Others Admin Admin Syntax from d j a n g o . c o n t r i b import admin from m o d e l s import Post , Comment c l a s s PostAdmin ( admin . ModelAdmin ) : l i s t d i s p l a y = ( t i t l e , datetime ) c l a s s CommentAdmin ( admin . ModelAdmin ) : l i s t d i s p l a y = ( text ,) admin . s i t e . r e g i s t e r ( Post , PostAdmin ) admin . s i t e . r e g i s t e r ( Comment , CommentAdmin )
List Page
Add an Entry
Auto Validation

More Related Content

Web Development Paradigms and djangoic approach to deal with them

  • 1. Introduction Forms Authentication Generic Views Caching Others Admin Web Development Paradigms and djangoic approach to deal with them. Lakshman Prasad Agiliq Solutions September 25, 2010
  • 2. Concepts and abstractions used to represent elements of a program
  • 3. Web Development Paradigms: Modeling common web patterns
  • 8. Webapp: Simple web application framework (with custom APIs)
  • 9. Lets examine the batteries
  • 10. Introduction Forms Authentication Generic Views Caching Others Admin How do I know about web development or django ? Active Djangonaut ? Part of a few popular open source django applications github.com/becomingGuru, github.com/agiliq ? Consulting and Development via ? Developed several custom proprietory django applications ? @becomingGuru
  • 11. Introduction Forms Authentication Generic Views Caching Others Admin Introduction Forms Authentication Generic Views Caching Others Admin
  • 12. Forms
  • 13. Save form data to a table
  • 14. Introduction Forms Authentication Generic Views Caching Others Admin Use a Model Form >>> from d j a n g o . f o r m s import ModelForm # C r e a t e t h e form c l a s s . >>> c l a s s A r t i c l e F o r m ( ModelForm ) : ... c l a s s Meta : ... model = A r t i c l e # C r e a t i n g a form t o add an a r t i c l e . >>> form = A r t i c l e F o r m ( ) # C r e a t i n g a form t o c h an ge an e x i s t i n g a r t i c l e . >>> a r t i c l e = A r t i c l e . o b j e c t s . g e t ( pk=1) >>> form = A r t i c l e F o r m ( i n s t a n c e= a r t i c l e )
  • 16. Introduction Forms Authentication Generic Views Caching Others Admin Model Syntax from d j a n g o . db import m o d e l s c l a s s P o s t ( m o d e l s . Model ) : t i t l e = m o d e l s . C h a r F i e l d ( m a x l e n g t h =100) t e x t = models . T e x t F i e l d ( ) datetime = models . DateTimeField ( ) c l a s s Meta : o r d e r i n g = ( ?d a t e t i m e , ) def unicode ( self ): return s e l f . t i t l e c l a s s Comment ( m o d e l s . Model ) : post = models . ForeignKey ( Post ) t e x t = models . T e x t F i e l d ( )
  • 17. Introduction Forms Authentication Generic Views Caching Others Admin Model API >>>from b l o g . m o d e l s import Post , Comment >>>p o s t = P o s t . o b j e c t s . a l l ( ) [ 0 ] >>>p o s t c o m m e n t s = p o s t . c om m en t s et . a l l ( )
  • 18. Introduction Forms Authentication Generic Views Caching Others Admin Save Foreign Keys
  • 19. Introduction Forms Authentication Generic Views Caching Others Admin Use Model Formset from d j a n g o . f o r m s . m o d e l s import m o d e l f o r m s e t f a c t o r y AuthorFormSet = m o d e l f o r m s e t f a c t o r y ( Au t ho r ) f o r m s e t = AuthorFormSet ( ) >>> p r i n t f o r m s e t <i n p u t t y p e= h i d d e n name= form?TOTAL FORMS v a l u e= 1 i d= i d f o r m ?TOTAL FORMS /> <i n p u t t y p e= h i d d e n name= form?INITIAL FORMS v a l u e= 0 i d= i d f o r m ?INITIAL FORMS /> <i n p u t t y p e= h i d d e n name= form?MAX NUM FORMS i d= i d f o r m ?MAX NUM FORMS /> <t r ><th> < l a b e l f o r= i d f o r m ?0?name>Name:</ l a b e l > </th><td> <i n p u t i d= i d f o r m ?0?name t y p e= t e x t name= form ?0?name m a x l e n g t h= 100 /> </td ></t r >
  • 20. Introduction Forms Authentication Generic Views Caching Others Admin Model Formset options f o r m s e t = AuthorFormSet ( q s=Au th o r . o b j e c t s . a l l ( ) , e x t r a =5) formset . i s v a l i d () formset . e r r o r s { name : T h i s f i e l d is required } formset . changed forms formset . save ()
  • 21. Introduction Forms Authentication Generic Views Caching Others Admin Form pre populated
  • 22. Introduction Forms Authentication Generic Views Caching Others Admin Forms dont have to save to a Model from d j a n g o import f o r m s c l a s s ContactForm ( f o r m s . Form ) : s u b j e c t = f o r m s . C h a r F i e l d ( m a x l e n g t h =100) message = f o r m s . C h a r F i e l d ( ) sender = forms . E m a i l F i e l d () c c m y s e l f = f o r m s . B o o l e a n F i e l d ( r e q u i r e d=F a l s e ) def s a v e ( s e l f ) : #Do a n y t h i n g ...
  • 24. Introduction Forms Authentication Generic Views Caching Others Admin Form Preview from d j a n g o . c o n t r i b . f o r m t o o l s . p r e v i e w import FormPreview from myapp . m o d e l s import SomeModel #Add a u r l ( r ? p o s t / $ , SomeModelFormPreview ( SomeModelForm ) ) , #D e f i n e form p r e v i e w c l a s s SomeModelFormPreview ( FormPreview ) : def done ( s e l f , r e q u e s t , c l e a n e d d a t a ) : # Do s o m e t h i n g w i t h t h e c l e a n e d d a t a , t h e n # r e d i r e c t t o a s u c c e s s page . r e t u r n H t t p R e s p o n s e R e d i r e c t ( / form / s u c c e s s )
  • 26. Introduction Forms Authentication Generic Views Caching Others Admin Form Wizard c l a s s C o n t a c t W i z a r d ( FormWizard ) : def done ( s e l f , r e q u e s t , f o r m l i s t ) : do something with the form data ( fo r m l is t ) return HttpResponseRedirect ( / r e d i r e c t / )
  • 28. Introduction Forms Authentication Generic Views Caching Others Admin Point to url pattern u r l p a t t e r n s += p a t t e r n s ( d j a n g o . c o n t r i b . a u t h . v i e w s , u r l ( r ? l o g i n /$ , l o g i n ) , u r l ( r ? l o g o u t /$ , l o g o u t ) , u r l ( r ? r e g i s t e r /$ , r e g i s t e r ) , u r l ( r ? p a s s r e s e t /$ , p a s s w o r d r e s e t ) , u r l ( r ? p a s s r e s e t 2 /$ , p a s s w o r d r e s e t d o n e ) , u r l ( r ? p a s s r e s e t c o n f i r m / ( ?P<u i d b 3 6 >[?w]+)/ , password reset confirm ) , u r l ( r ? p a s s r e s e t c o m p l e t e /$ , password reset complete ) , )
  • 29. Introduction Forms Authentication Generic Views Caching Others Admin Login Required from d j a n g o . c o n t r i b . a u t h . d e c o r a t o r s import login required @ l o g i n r e q u i r e d ( r e d i r e c t f i e l d n a m e= r e d i r e c t t o ) def my view ( r e q u e s t ) : ...
  • 30. Introduction Forms Authentication Generic Views Caching Others Admin Authentication backends class SettingsBackend : A u t h e n t i c a t e a g a i n s t t h e s e t t i n g s ADMIN LOGIN and ADMIN PASSWORD . def a u t h e n t i c a t e ( s e l f , username=None , p a s s w o r d=None ) i f l o g i n v a l i d and p w d v a l i d : return user r e t u r n None def g e t u s e r ( s e l f , u s e r i d ) : try : r e t u r n U s e r . o b j e c t s . g e t ( pk=u s e r i d ) except U s e r . D o e s N o t E x i s t : r e t u r n None
  • 33. Introduction Forms Authentication Generic Views Caching Others Admin Generic Views from d j a n g o . c o n f . u r l s . d e f a u l t s import ? from d j a n g o . v i e w s . g e n e r i c . s i m p l e import d i r e c t t o t e m p l a t e urlpatterns = patterns ( , ( ? about /$ , d i r e c t t o t e m p l a t e , { t e m p l a t e : a b o u t . html }) )
  • 34. Introduction Forms Authentication Generic Views Caching Others Admin Object based generic views
  • 35. Introduction Forms Authentication Generic Views Caching Others Admin Display objects and their lists from d j a n g o . v i e w s . g e n e r i c . l i s t d e t a i l import object detail , object list u r l ( ( r ? o b j e c t s / page ( ? P<page >[0 ?9]+)/ $ , object list , dict ( info dict )) , ( r ? o b j e c t s / ( ?P<i d >[0 ?9]+)/ $ , object detail , dict ( info dict )) , )
  • 36. Introduction Forms Authentication Generic Views Caching Others Admin List of generic views django . views . g e n e r i c . simple . d i r e c t t o t e m p l a t e django . views . g e n e r i c . simple . r e d i r e c t t o django . views . g e n e r i c . l i s t d e t a i l . o b j e c t l i s t django . views . g e n e r i c . l i s t d e t a i l . o b j e c t d e t a i l django . views . g e n e r i c . create update . c r e a t e o b j e c t django . views . g e n e r i c . create update . update object django . views . g e n e r i c . create update . d e l e t e o b j e c t
  • 37. Normalized data is for sissies - Cal Henderson
  • 38. Introduction Forms Authentication Generic Views Caching Others Admin Di?erent blocks need di?erent caching durations
  • 39. Introduction Forms Authentication Generic Views Caching Others Admin Generally Memcache Every page CACHE BACKEND = memcached : / / 1 2 7 . 0 . 0 . 1 : 1 1 2 1 1 / CACHE BACKEND = memcached : / / 1 7 2 . 1 9 . 2 6 . 2 4 0 : 1 1 2 1 1 ; 172.19.26.242:11212;172.19.26.244:11213/
  • 40. Introduction Forms Authentication Generic Views Caching Others Admin Implement a caching decorator from d j a n g o . c o r e . c a c h e import c a c h e def c a c h e f o r ( s e c o n d s , f e t c h =0): def c a c h e i t ( f u n c ) : def d e c o f u n c ( s e l f ) : v a l = cache . get ( s e l f . g e t c a c h e k e y ( f e t c h )) i f not v a l : val = func ( s e l f ) cache . s e t ( s e l f . g e t c a c h e k e y ( f e t c h ) , val , seconds ) return v a l return deco func return c a c h e i t
  • 41. Introduction Forms Authentication Generic Views Caching Others Admin Apply on the blocks class TwitterBlock ( TwitterSearchBlock ) : t e m p l a t e n a m e = t w i t t e r u s e r b l o c k . html a j a x t e m p l a t e = t w e e t s u s e r . html @ c a c h e f o r ( 6 0 ? 6 0 , f e t c h =1) def f e t c h d a t a ( s e l f ) : tw = T w i t t e r ( e m a i l= umoja com ) u s e r t w e e t s = tw . s t a t u s e s . u s e r t i m e l i n e ( s c r e e n n a m e= s e l f . d a t a ) r e t u r n u s e r t w e e t s , None
  • 42. Introduction Forms Authentication Generic Views Caching Others Admin Di?erent cache Backends ? Database ? File System ? Local Memory ? Dummy- For Development
  • 43. Introduction Forms Authentication Generic Views Caching Others Admin More Paradigms ? Internationalization ? Localization ? Humanization ? CSRF Protection ? Pagination ? Sorting ? Data grid ? Sorl Thumbnail
  • 45. Introduction Forms Authentication Generic Views Caching Others Admin Admin by models alone
  • 46. Introduction Forms Authentication Generic Views Caching Others Admin Admin Syntax from d j a n g o . c o n t r i b import admin from m o d e l s import Post , Comment c l a s s PostAdmin ( admin . ModelAdmin ) : l i s t d i s p l a y = ( t i t l e , datetime ) c l a s s CommentAdmin ( admin . ModelAdmin ) : l i s t d i s p l a y = ( text ,) admin . s i t e . r e g i s t e r ( Post , PostAdmin ) admin . s i t e . r e g i s t e r ( Comment , CommentAdmin )