2008年7月29日 星期二
python imaging library
If model in Django wants to use ImageField, we must install python imaging library
2008年7月25日 星期五
template
template object & context object:
ex:
from django.template import Template, Context
a=Template("<p>hello {{name}} </p>")
b=Context({ 'name': 'Peter' } )
a.render(b)
{{ }} in template define the variable
context is a dictionary that map variable to value
render function replace the value with value
call method in {{ }}:
no () & no arguments
ex:
{{ dog.bark }}
list in {{}}:
ex:
{{items.2}}
dictionary in {{}}:
ex:
{{ Person.name }}
define a method that can not be executed by template
ex:
def test(self):
hello
test.alters_data=true
template tag:
if & else:
ex:
{% if isHot %}
{{isHot}}
{% else %}
not Hot
{% endif %}
and , or, not, can be used in if
for:
ex:
{% for name in nameList %}
{{ name}}
{% endfor %}
for & reverse:
ex:
{% for name in nameList reversed %}
{{name}}
{% endfor %}
forloop.counter:
the number of times the loop has been entered
forloop.first:
forloop.revcounter:
forloop.last:
forloop.parentloop:
reference to the forloop object for the parent loop
ifequal / ifnotequal:
ex:
{% ifequal a b %}
test
{% endifequal %}
comment:
ex:
{# this is a comment #}
filter:
change variable, use | with filter name
ex:
date filter:
{{ tempDate | date: "F j, Y" }}
2008年7月18日 星期五
exception
ex:
ckass Bad(Exception):
pass
def test():
raise Bad(), "test bad"
try:
test()
except Bad, info:
print "bad", info
else:
print "else"
finally:
print "finally"
assert:
raise AssertionError when test evaluates to false
ex:
assert x<=3, 'x must be larger than 3'
raise:
ex1: raise object
class A:
pass
def test():
raise A()
ex2: raise string
message="Error"
def test():
raise message
2008年7月14日 星期一
view function
first parameter must be HttpRequest
the other parameters are the string matched by ( ) of urlpatterns
def hours_ahead(request, offset):
offset=int(offset)
dt= datetime.datetime.now()+ datetime.timedelta(hours=offset)
html="<html><body>In %s hours(s), it will be %s.</body></html>"% (offset,dt)
return HttpResponse(html)
2008年7月13日 星期日
class method & static method
class method:
ex:def test(cls):
print('class method')
test=classmethod(test)
static method:
ex:
def test()
print('static method')
test=staticmethod(test)
url mapping
settings.py has a variable ROOT_URLCONF
ROOT_URLCONF decides the python file for routing
ROOT_URLCONF is urls.py by default
when a request comes in, Django loads ROOT_URLCONF and find the match between request url & urlpatterns
when pattern found, the associated view function is called( the function is passed HttpRequest object as first parameter)
the view function will return an HttpResponse object
define urlpatterns
ex:
urlpatterns = patterns( '', ( r'^test/$', testFunction) )
match /test/ , if request is /test/, testFunction is called
define view function:
ex:
def test(request):
now=datetime.datetime.now()
html= "<html><body>It is now %s.</body></html>" % now
return HttpResponse(html)
create a project, create an app, run the server, path, timezone
create a projct
django-admin.py startproject newSitecreate an app in the project:
python manage.py startapp books
create __init__.py, models.py, views.py in books directory
run the server:
python manage.py runserver
running at 127.0.0.0.1:8000
python manage.py runserver 0.0.0.0 8888
listen on any network interface, on port 8888
set path for django project
add django_site.pth under /Library/Python/2.5/site-packages
ex:
django_site.pth:
/Volumes/Data/django_project/
time zone
in settings.py
TIME_ZONE = 'Asia/Taipei'
__name__ & __main__
when the file is run as a top-level program, __name__ is set as __main__
when the file is imported, __name__ is set to the module's name
Hence, we can use __name__ to do unit test.
If __name__ == __main__, we execute unit test
if __name__ != __main__, unit test is not executed
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