Django REST Framework: Dynamic Fields in Serializers

Here’s the use case, I need to add some extra fields to my serializer depending on a request. For example, if the query string contains “extra=true”, then add the extra fields. Luckily, serializers get a “context” argument when they are initialized. We can use this to customize our serializers as needed.

The fields defined on a serializer are available in a instance variable named “fields”. So we can add/delete/edit fields from it. Let’s see an example:

Please note, here we have used another serializer (UserLocationSerializer) from inside our main serializer. The second one is being initialized by us. So it would not get the context. If we need to do something down there as well, then we need to pass it ourselves.

Now the second serializer will get the request too and we can use the same way to customize it!

Python/Django: Running multiple commands in subprocesses

Here’s the scneario:

I have 4-5 different commands which I need to run every time I want to test my app. So I decided to write one command to rule them all. I run this one command and it runs the others using the subprocess module. It stores the processes created in a list. Then it goes to sleep inside a while loop waiting for a KeyboardInterrupt exception (which is fired when you press Ctrl + C – that is you send an interrupt signal from your keyboard). When this exception occurs, we iterate through the process ids we stored and kill them all. Simple, No?

Talk is cheap, here’s the code:

So this is how it looks on my machine:

Screen Shot 2015-09-29 at 5.16.44 PM