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Force browser to clear cache
...Shawn Version-control wise you could render the <link /> tags dynamically and inject the application's version as a query string parameter. Alternatively, some CMSes will have a "client resources version" as a CMS-wide setting that is appended - the site's admin can manually increase that vers...
When saving, how can you check if a field has changed?
...
Essentially, you want to override the __init__ method of models.Model so that you keep a copy of the original value. This makes it so that you don't have to do another DB lookup (which is always a good thing).
class Person(models.Model):
name = models.CharF...
How to change the Push and Pop animations in a navigation based app
...t common, everyday transitions (such as an ordinary slide), you do have to all the work of implementing a full custom transition.
Here's how to do it ...
1. You need a custom UIViewControllerAnimatedTransitioning
You need a bool of your own like popStyle . (Is it popping on, or popping off?)
You m...
Continuously read from STDOUT of external process in Ruby
...iven by blender line by line to update a progress bar in a GUI. It's not really important that blender is the external process whose stdout I need to read.
...
putting current class as return type annotation [duplicate]
...e. Instead, they are preserved in __annotations__ in string form. This is called Postponed Evaluation of Annotations, introduced in PEP 563.
Also note:
Deprecation policy
Starting with Python 3.7, a __future__ import is required to use the
described functionality. No warnings are raised...
How can I initialize base class member variables in derived class constructor?
...ince it would destroy encapsulation. Instead, create a constructor in A to allow B (or any subclass of A) to initialize them:
class A
{
protected:
A(int a, int b) : a(a), b(b) {} // Accessible to derived classes
// Change "protected" to "public" to allow others to instantiate A.
private:
...
How to get a JavaScript object's class?
...
ES5 has aditionally Object.getPrototypeOf()
– Christoph
Aug 8 '09 at 18:52
29
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Token Authentication for RESTful API: should the token be periodically changed?
...
It is good practice to have mobile clients periodically renew their authentication token. This of course is up to the server to enforce.
The default TokenAuthentication class does not support this, however you can extend it to achieve this functionality.
For example:
from...
Removing multiple keys from a dictionary safely
...
Why not like this:
entries = ('a', 'b', 'c')
the_dict = {'b': 'foo'}
def entries_to_remove(entries, the_dict):
for key in entries:
if key in the_dict:
del the_dict[key]
A more compact version was provided by mattbornski using dict.pop()
...
What's wrong with nullable columns in composite primary keys?
...
Primary keys are for uniquely identifying rows. This is done by comparing all parts of a key to the input.
Per definition, NULL cannot be part of a successful comparison. Even a comparison to itself (NULL = NULL) will fail. This means a key containing NULL would not work.
Additonally, NULL is al...