how serialize django model to gRPC message?

[diegoduncan21]

"There is an easy way to serialize django model to gRPC message using django_grpc.serializers.serialize_model."

i was reading the code trying to understand but i can't, do you have an example code of this?

thanks.

[markdoerr]

Hi Stan, first of all: thanks for this great project: it is very valuable and will be more in the future, if gRPC gains more ground ! I have the same problem as @diegoduncan21 : if you explain a little, what you had in mind with the serializers, we might help you writing an example. It sounds like a great idea to find a generic solution for CRUD actions via gRPC. Thanks, mark

[gluk-w]

I apologize for the late response!

I wanted to have universal solution for converting model instance to protobuf. But I don't even remember how it worked because never used it :(

I found a better approach by defining .to_protobuf() method for models that need to be serialized. The method should return instance of protobuf like this:

from django.db import models

from myproto import page_pb2  # this is generated python code out of proto definition 

class Page(models.Model):
  title = models.CharField(max_length=255)
  body = models.TextField()

  def to_protobuf(self):
    return page_pb2.Page(title=self.title, body=self.body)

Then in the servicer I can reuse that every time Page message must be returned.

Regards, Stan

[markdoerr]

Thanks a lot, Stan, this looks reasonable. I will try it (hopefully) tonight. Cheers, mark

[markdoerr]

Hi Stan, I started to implement your suggestion, but ran into some issues: How would you serialise Foreign keys or, even worse, ManyToMany fields in the way you proposed ? How would you create / update fields with ManyToMany relations or Foreign keys via gRPC ? Looks not trivial too me ...

[gluk-w]

You have to do that manually and copy model properties to protobuf structure like this:

  def to_protobuf(self):
    categories = [page_pb2.Category(title=cat.title) for cat in self.categories.all()]
    return page_pb2.Page(title=self.title, body=self.body, categories=categories)

This is especially true if your django models differ from protobuf

[markdoerr]

Thanks, Stan, interesting construct: in your example categories will be a list of protobuf messages of type Category containing only the category title. And this list you put into the Page protobuf message - is the category information not lost now in your example case, because you will send a list of all categories with the Page message ? (ideally only the category of the page instance that is to be serialised should be returned - or am I missing something ?)

[gluk-w]

It depends on your protobuf structure. There can be one category per page or multiple, they can be defined as repeated strings or separate structures.

Ideally, there would be Category.to_protobuf() so it could be called in Page.to_prptobuf()

[sumitsharansatsangi]

Hi Stan , In the documentation , I found There is an easy way to serialize django model to gRPC message using django_grpc.serializers.serialize_model.

Can you please add an example how to use it?

Thank you Sumit

[yswtrue]

same confuse here