Graphene: Add totalCount field to connections

[daironmichel]

Hi guys,

Looking at GraphQL specification about pagination here, I see they have a totalCount field on the connection which graphene currently does not have

{
  hero {
    name
    friendsConnection(first:2 after:"Y3Vyc29yMQ==") {
      totalCount
      edges {
        node {
          name
        }
        cursor
      }
      pageInfo {
        endCursor
        hasNextPage
      }
    }
  }
}

Will it be possible to add totalCount field to connections or to the pageInfo?

[daironmichel]

BTW, good job with the docs and version 1.0

[mjtamlyn]

At the moment, connections are implemented according to the Relay cursor spec - which doesn't mention totalCount. You can create your own connection class (and field) if you want to add it

[daironmichel]

thanks for your response @mjtamlyn,
can you please give me an example on how will I get the framework to use my own connection class?

[ekampf]

Need to debug to make sure it works but should be something like

class MyConnection(Connection):
    class Meta:
        node = UserType

    total_count = Int()

some_query = ConnectionField(MyConnection)

def resolve_some_query(self, *_):
  edges = .. create edges from query ...
  total_count = .. calculate total ...
  return MyConnection
      total_count=total_count,
      edges=edges,
      page_info=PageInfo(
            start_cursor=start_cursor.urlsafe() if start_cursor else '',
            end_cursor=end_cursor,
            has_previous_page=has_previous_page,
            has_next_page=ndb_iter.has_next()
        )
  )

[syrusakbary]

Eran example should now work.

I added also a testcase to ensure resolvers can return connection instances: c7929234294a181993158b4439c24006e9ed1ebd

[daironmichel]

Thanks man. Nice work!

On Oct 1, 2016 1:54 PM, "Syrus Akbary" [email protected] wrote:

Eran example should now work.

I added also a testcase to ensure that resolvers can return connection
instances: c792923
https://github.com/graphql-python/graphene/commit/c7929234294a181993158b4439c24006e9ed1ebd

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[ariannedee]

Is there a way to resolve total_count within the MyConnection class?

[theGleam]

from graphene import ObjectType, Connection, Node, Int
from graphene_django import DjangoObjectType
from graphene_django.fields import DjangoConnectionField
from ..models import MyObject

class MyConnection(Connection):
    class Meta:
        abstract = True

    total_count = Int()

    def resolve_total_count(root, info, **kwargs):
        return root.length



class MyObjectType(DjangoObjectType):
    class Meta:
        model = MyObject
        interfaces = (Node, )
        connection_class = MyConnection


class Query(ObjectType):
    my_objects = DjangoConnectionField(MyObjectType)

[QFXC]

In my case, this problem was solved by using this custom Connection.

import graphene
class MyConnection(graphene.relay.Connection):

    class Meta:
        abstract = True

    total_count = graphene.Int()

    def resolve_total_count(root, info):
        return len(root.iterable) # And no, root.iterable.count() did not work for me.

What is great about this is that if I replace return len(root.iterable) with return 0, django-debug-toolbar tells me that I still have the same amount of queries in both cases. So, no N+1 problem. And, I can use the ConnectionField rather than DjangoConnectionField in my Query classes.