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graphql - 如何从外部 API 的数组中获取变量？

问题描述

我从 Apollo GraphQL（使用 Axios）开始，当外部 API 发送 ARRAY 时我遇到了问题。我无法获取对象内的变量。我已经尝试了多种方法，但在任何地方都找不到帮助。

const axios = require ('axios');


const {GraphQLObjectType, GraphQLSchema, GraphQLInt,
     GraphQLList, GraphQLString } = require('graphql');


const FeedingType = new GraphQLObjectType({
    name: 'Feeding',
    fields: () => ({
        sentry_objects : {type : new GraphQLList(SentryType)},
    })
})

//Sentry Objects
const SentryType = new GraphQLObjectType({
    name: 'Sentry',
    fields: () => ({
        designation : {type : GraphQLString},
    })
})

//Root Query
const RootQuery = new GraphQLObjectType({
    name: 'RootQueryType',
    fields: {
        sentry: {
            type: new GraphQLList(SentryType),
            resolve(parent, args){
                return axios
                .get('https://api.nasa.gov/neo/rest/v1/neo/sentry?is_active=true&page=0&size=50&api_key=DEMO_KEY')
                .then(res => res.data);
            }
        },

这就是来自 API 的 JSON：

{
  "links": {
    "next": "https://api.nasa.gov/neo/rest/v1/neo/sentry?is_active=true&page=1&size=50&api_key=DEMO_KEY",
    "self": "https://api.nasa.gov/neo/rest/v1/neo/sentry?is_active=true&page=0&size=50&api_key=DEMO_KEY"
  },
  "page": {
    "size": 50,
    "total_elements": 908,
    "total_pages": 19,
    "number": 0
  },
  "sentry_objects": [
    {
      "links": {
        "near_earth_object_parent": "https://api.nasa.gov/neo/rest/v1/neo/3012393?api_key=DEMO_KEY",
        "self": "https://api.nasa.gov/neo/rest/v1/neo/sentry/3012393?api_key=DEMO_KEY"
      },
      "spkId": "3012393",
      "designation": "1979 XB",
      "sentryId": "bJ79X00B",
      "fullname": "(1979 XB)",
      "year_range_min": "2056",
      "year_range_max": "2113",
      "potential_impacts": "2",
      "impact_probability": "7.36e-07",
      "v_infinity": "23.9194972826087",
      "absolute_magnitude": "18.53",
      "estimated_diameter": "0.662",
      "palermo_scale_ave": "-2.82",
      "Palermo_scale_max": "-3.12",
      "torino_scale": "0",
      "last_obs": "1979-Dec-15.42951",
      "last_obs_jd": "2444222.92951",
      "url_nasa_details": "https://cneos.jpl.nasa.gov/sentry/details.html#?des=1979+XB",
      "url_orbital_elements": "http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=3012393;orb=1",
      "is_active_sentry_object": true,
      "average_lunar_distance": 14.2337865829
    },
}

试图获取“sentry_objects”变量，使用“designation”进行测试，但我只是收到如下错误：

{
  "errors": [
    {
      "message": "Expected Iterable, but did not find one for field RootQueryType.sentry.",
      "locations": [
        {
          "line": 2,
          "column": 3
        }
      ],
      "path": [
        "sentry"
      ]
    }
  ],
  "data": {
    "sentry": null
  }
}

感谢您阅读：）

标签： graphqlapollo

解决方案

在您的RootQuery解析器中，您仅从承诺res.data对象返回，但您应该返回该res.data.sentry_object对象。

就像是：

const RootQuery = new GraphQLObjectType({
    name: 'RootQueryType',
    fields: {
        sentry: {
            type: new GraphQLList(SentryType),
            resolve(parent, args) {
                return axios
                    .get('https://api.nasa.gov/neo/rest/v1/neo/sentry?is_active=true&page=0&size=50&api_key=DEMO_KEY')
                    .then(res => {
                        // HERE: return the sentry_objects 
                        console.log(res.data.sentry_objects)
                        return res.data.sentry_objects
                    });
            }
        },
    }
})

希望能帮助到你。

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