greff 0.0.5a0

rich graphql client in python

greff

I wanted an animal name, but most of them already used in pypi :(, the name pronounced greph

what is it

greff creates python classes from graphql response.

what is it not

• doesn't check for typing, you have pydantic for it
• dataclass, although you can use the dataclasses syntax to create classes greff is for graphql and it adds graphql attributes behind the sence

current stage

in the current stage its not ready for release, it is only possible (for now) to query data

vision / example

import requests
import greff


@greff.define_type(queryname="authors")
class ParentAuthor(greff.Model):
    name: str
    age: int = 0


@greff.define_type()
class Author(ParentAuthor):
    extra_field: str


@greff.define_type()
class SimpleAuthor(ParentAuthor):
    pass


class MyGraphqlClient(greff.HTTPClient):

  # we implement the graphql posting function ourself
  # since it can very from diffrent implementations
  def request(self, query: str) -> dict:
      response = requests.post("http://localhost:8000/graphql", json={"query": query}, verify=False)
      response.raise_for_status()
      return response.json()


# create our charryplate graphql client
graphql = MyGraphqlClient()

# graphql equivelent
# query {
#   authors {
#     ... frag
#   }
# }
# fragment frag on Author {
#   name
# }
# 
query = graphql.query((
        (ParentAuthor, (
            ParentAuthor.query.name,
        )),
    ),
)

# graphql response 
# {
#   "data": {
#     "authors": [
#       {
#         "name": "Michael Crichton",
#         "__typename": "Author"
#       }
#     ]
#   }
# }
for author in query:
    print(type(author), author.name)

output

<class '__main__.Author'> Michael Crichton

why did it return Author instance and not ParentAuthor instance?

if you look closely at the response

{
  "data": {
    "authors": [
      {
        "name": "Michael Crichton",
        "__typename": "Author"
      }
    ]
  }
}

ParentAuthor is implementor for Author and SmallAuthor and in our query the __typename returned Author, so greff automatically created the correct python instace