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Django Worst PracticesDaniel Greenfeld

Tuesday, April 19, 2011

Django Worst Practices

Whole project in one app




All your stuff in one place!




All your stuff in one place!No need to worry about bugfixes or enhancements!



pydanny: pwd/Users/pydanny/projects/enterprise/settingspydanny: ls -ltotal 24-rw-r--r-- 1 pydanny staff 0 Apr 18 22:38 __init__.pylrwxr-xr-x 1 pydanny staff 21 Apr 18 22:42 dev.py -> /Users/pydanny/dev.pylrwxr-xr-x 1 pydanny staff 22 Apr 18 22:42 prod.py -> /Users/pydanny/prod.pylrwxr-xr-x 1 pydanny staff 25 Apr 18 22:42 staging.py -> /Users/pydanny/staging.py

Symlink your settings folder!Cause you’ll remember to do this with each server setup...



Database Choices



• Use a relational database to store ill-defined hierarchical data!

Database Choices



• Use a relational database to store ill-defined hierarchical data!

• Use NoSQL to store tabular data!

Database Choices


Django Worst Practices <%python scope="global"> # declare global variables, accessible # across this component's generated module message1 = "this is message one." message2 = "this is message two." message3 = "doh, im message three." </%python> <%python> # reference the global variables m.write("message one: " + message1) m.write("message two: " + message2) # we want to assign to message3, # so declare "global" first global message3 message3 = "this is message three." m.write("message three: " + message3) </%python>



Who needs caching?

<%python scope="global"> # declare global variables, accessible # across this component's generated module message1 = "this is message one." message2 = "this is message two." message3 = "doh, im message three." </%python> <%python> # reference the global variables m.write("message one: " + message1) m.write("message two: " + message2) # we want to assign to message3, # so declare "global" first global message3 message3 = "this is message three." m.write("message three: " + message3) </%python>



Who needs caching?

Performance awesomeness!




Who needs caching?

Performance awesomeness!

Replaces pesky django templates!




Use XSLT for awesome performance!

<?xml version="1.0" encoding="UTF-8"?><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"> <xsl:output method="xml" indent="yes"/> <xsl:template match="/persons"> <root> <xsl:apply-templates select="person"/> </root> </xsl:template> <xsl:template match="person"> <name username="{@username}"> <xsl:value-of select="name" /> </name> </xsl:template> </xsl:stylesheet>



Put critical business logic in...



• The templates




• The templates

• settings




• The templates

• settings

• The context processors




• The templates

• settings

• The context processors

• Middleware!




Use metaclasses instead of abstract models!



from django.db import models

blog2_fields = [

models.CharField(“title”, max_length=50),

models.TextField(“note”)

]

In settings:



Present usingDifferent fonts

Dark textDire backgrounds


Django Worst PracticesDon’t use

http://djangopackages.com

Invent everything yourself!


