Question

我已经编写了一些graphql模式，并使用pyramida进行了部署。 Prisma使用.graphql，type Query，type Mutation生成了一些type Subscription文件。有一个从docker运行的prisma服务器正在与MySQL数据库联系。现在，我想使用Ariadne编写一些API函数，并使用Prisma查询联系数据库。我该如何实现？

提供给pyramida的GraphQL架构

datamodel.prisma

type User {
  id: ID! @id 
  name: String!
}

生成的graphql文件的示例

prisma.graphql

type Query {
  user(where: UserWhereUniqueInput!): User
  users(where: UserWhereInput, orderBy: UserOrderByInput, skip: Int, after: String, before: String, first: Int, last: Int): [User]!
  usersConnection(where: UserWhereInput, orderBy: UserOrderByInput, skip: Int, after: String, before: String, first: Int, last: Int): UserConnection!
  node(id: ID!): Node
}

使用ariadne尝试连接到数据库的API的代码段

我正在尝试执行users查询，即从数据库中获取所有用户。

api.py

from ariadne import gql, load_schema_from_path, QueryType, make_executable_schema
from ariadne.asgi import GraphQL

schema_files_path = "/root/manisha/prisma/generated/prisma.graphql"
schema = load_schema_from_path(schema_files_path)

query = QueryType()

@query.field("users")
def resolve_users(_, info):
    ...


schema = make_executable_schema(schema, query)
app = GraphQL(schema, debug=True)

使用uvicorn运行服务器 uvicorn api:app --reload --port 7000

使用下面的查询，我可以吸引所有用户在移动棱镜。

{
  users{
    name
    id

  }
}

Screenshot of prisma playground for getting all users from database

尝试使用ariadne resolve_users解析器进行相同的操作。

给我下面的错误：

ERROR: Expected Iterable, but did not find one for field Query.users.

GraphQL request (2:3)
1: {
2:   users {
     ^ 
3:     id
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/dist-packages/graphql/execution/execute.py", line 675, in complete_value_catching_error
    return_type, field_nodes, info, path, result
  File "/usr/local/lib/python3.6/dist-packages/graphql/execution/execute.py", line 750, in complete_value
    result,
  File "/usr/local/lib/python3.6/dist-packages/graphql/execution/execute.py", line 766, in complete_value
    cast(GraphQLList, return_type), field_nodes, info, path, result
  File "/usr/local/lib/python3.6/dist-packages/graphql/execution/execute.py", line 807, in complete_list_value
    "Expected Iterable, but did not find one for field"
TypeError: Expected Iterable, but did not find one for field Query.users.

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/local/lib/python3.6/dist-packages/graphql/execution/execute.py", line 351, in execute_operation
    )(type_, root_value, path, fields)
  File "/usr/local/lib/python3.6/dist-packages/graphql/execution/execute.py", line 441, in execute_fields
    parent_type, source_value, field_nodes, field_path
  File "/usr/local/lib/python3.6/dist-packages/graphql/execution/execute.py", line 612, in resolve_field
    field_def.type, field_nodes, info, path, result
  File "/usr/local/lib/python3.6/dist-packages/graphql/execution/execute.py", line 688, in complete_value_catching_error
    self.handle_field_error(error, field_nodes, path, return_type)
  File "/usr/local/lib/python3.6/dist-packages/graphql/execution/execute.py", line 703, in handle_field_error
    raise error
  File "/usr/local/lib/python3.6/dist-packages/graphql/execution/execute.py", line 675, in complete_value_catching_error
    return_type, field_nodes, info, path, result
  File "/usr/local/lib/python3.6/dist-packages/graphql/execution/execute.py", line 750, in complete_value
    result,
  File "/usr/local/lib/python3.6/dist-packages/graphql/execution/execute.py", line 766, in complete_value
    cast(GraphQLList, return_type), field_nodes, info, path, result
  File "/usr/local/lib/python3.6/dist-packages/graphql/execution/execute.py", line 807, in complete_list_value
    "Expected Iterable, but did not find one for field"
graphql.error.graphql_error.GraphQLError: Expected Iterable, but did not find one for field Query.users.

Screenshot of error from ariadne

Answer 1

由于prisma尚不支持python客户端，因此以下代码可作为一种解决方法，用于联系Ariadne的prisma服务器。

from ariadne import gql, load_schema_from_path, QueryType, make_executable_schema 
from ariadne.asgi import GraphQL 

import requests 

prisma_url = "your-prisma-endpoint" 
schema_files_path = "/root/manisha/prisma/generated/prisma.graphql" 
schema = load_schema_from_path(schema_files_path) 

query = QueryType() 


def make_call_to_prisma(info): 
    data = info.context["request"]._body 
    resp = requests.post( 
        url=prisma_url, headers={"content-type": "application/json"}, data=data 
    ) 
    return resp 


@query.field("users") 
def resolve_users(_, info, where=None): 
    result = make_call_to_prisma(info) 
    print(result.json()) 
    return result.json()["data"]["users"] 


schema = make_executable_schema(schema, query) 
app = GraphQL(schema, debug=True)

将prisma graphql查询与ariadne集成

1 个答案: