python - 如何使用 Python 获取 GraphQL 模式？

Question

有很多 GUI 客户端，如 GraphQL Playground、GraphiQl 等，能够从 URL 获取 GraphQL 模式。如何使用 Python 获取模式？

Answer 1

来自规范:

A GraphQL server supports introspection over its schema. This schema is queried using GraphQL itself, creating a powerful platform for tool‐building... The schema introspection system is accessible from the meta‐fields __schema and __type which are accessible from the type of the root of a query operation.

GraphQL Playground 和 GraphiQL 等工具利用内省(introspection)来获取有关模式的信息。您不需要任何其他工具或库来进行内省(introspection)查询——因为它只是一个 GraphQL 查询，您将以与向端点发出任何其他请求相同的方式发出请求(使用 requests 例如)。

这是来自 graphql-core 的完整内省(introspection)查询:

introspection_query = """
  query IntrospectionQuery {
    __schema {
      queryType { name }
      mutationType { name }
      subscriptionType { name }
      types {
        ...FullType
      }
      directives {
        name
        description
        locations
        args {
          ...InputValue
        }
      }
    }
  }
  fragment FullType on __Type {
    kind
    name
    description
    fields(includeDeprecated: true) {
      name
      description
      args {
        ...InputValue
      }
      type {
        ...TypeRef
      }
      isDeprecated
      deprecationReason
    }
    inputFields {
      ...InputValue
    }
    interfaces {
      ...TypeRef
    }
    enumValues(includeDeprecated: true) {
      name
      description
      isDeprecated
      deprecationReason
    }
    possibleTypes {
      ...TypeRef
    }
  }
  fragment InputValue on __InputValue {
    name
    description
    type { ...TypeRef }
    defaultValue
  }
  fragment TypeRef on __Type {
    kind
    name
    ofType {
      kind
      name
      ofType {
        kind
        name
        ofType {
          kind
          name
          ofType {
            kind
            name
            ofType {
              kind
              name
              ofType {
                kind
                name
                ofType {
                  kind
                  name
                }
              }
            }
          }
        }
      }
    }
  }
"""