GraphQL 自定义指令强制执行值限制

Question

我需要在 INPUT_FIELD_DEFINITION 上创建一个自定义指令，以检查提供的枚举值是否未更改为之前的“状态”（业务逻辑是状态必须为未批准 - > 已批准-> 已取消 -> 已完成）但不太清楚如何在枚举类型的构造函数中映射值。

我的所有代码都可以在 github

我正在使用 nextJs 后端功能和 neo4j 数据库，为整个模式生成解析器。

// order Schema

export const order = gql`
  type Order {
    id: ID! @id
    state: OrderState!
    user: User! @relationship(type: "MADE", direction: IN)
    createdAt: DateTime! @timestamp(operations: [CREATE])
    products: [Product!] @relationship(type: "INCLUDE", direction: OUT)
  }

  enum OrderState {
    UNAPPROVED
    APPROVED
    CANCELLED
    FULFILLED
  }
`;

export const extendOrder = gql`
  extend input OrderCreateInput {
    state: OrderState!
  }
`;

我想创建 @checkState 指令来检查更新 state 是否有效

我使用了 GraphQL Tools docs 中的基本示例，但它包含字符串值。如果有任何帮助，我将不胜感激。

Answer 1

我没有使用自定义指令，而是使用 graphql-middleware 库来创建仅在使用 updateOrders 突变时触发的中间件。

Middleware

import { ValidationError } from "apollo-server-micro";
import { IMiddleware } from "graphql-middleware";
import { Order } from "pages/api/graphql";

export const checkStateMiddleware: IMiddleware = {
  Mutation: {
    updateOrders: async (resolve, parent, args, ctx, info) => {
      const { where, update } = args;

      const [existing] = await Order.find({
        ...where,
      });

      const states = ["UNAPPROVED", "APPROVED", "CANCELLED", "FULLFIELD"];

      const currentState = states.indexOf(existing.state);
      const toBeUpdatedState = states.indexOf(update.state);

      if (toBeUpdatedState < currentState) {
        throw new ValidationError("Can't update value with previous state.");
      }

      return resolve(parent, args);
    },
  },
};

然后我将它应用到 pages/api/graphql.ts

//...
import { applyMiddleware } from "graphql-middleware";
//...
const schemaWithMiddleware = applyMiddleware(schema, checkStateMiddleware);

const apolloServer = new ApolloServer({ schema: schemaWithMiddleware });
//...

GraphQL 自定义指令强制执行值限制

GraphQL Custom directive enforcing value restrictions

neo4j

graphql

next.js