Node/Express中MapQuest API调用遇'body used already'错误排查

使用MapQuest API结合node-geocoder实现地理编码时，首次Postman请求成功，但后续所有请求均失败，报错：

HttpError: body used already for: https://www.mapquestapi.com/geocoding/v1/address?key=

相关代码如下：

geoCoder.js 配置 #

const NodeGeocoder = require('node-geocoder');

const options = {
  provider: process.env.GEOCODER_PROVIDER,
//   fetch: customFetchImplementation,
  httpAdapter: 'https',
  apiKey: process.env.GEOCODER_API_KEY,
  formatter: null
};

const geocoder = NodeGeocoder(options);

module.exports = geocoder

Mongoose HomeSchema #

const mongoose = require('mongoose')
const geocoder = require('../utils/geocoder')


const HomeSchema = new mongoose.Schema({
    homeId: {
        type: String,
        required: [true, 'Please add a home ID'],
        unique: true,
        trim: true,
        maxlength: [10, 'Home ID must be less than 10 characters']
    },
    address: {
        type: String,
        required: [true, 'Please add an address']
    },
    location: {
        type: {
          type: String, 
          enum: ['Point'], 
        },
        coordinates: {
          type: [Number],
          index: '2dsphere'
        },
        formattedAddress: String
      },
    createdAt: {
        type: Date,
        default: Date.now
    }
})

// Geocode & create location
HomeSchema.pre('save', async function(next) {
    const loc = await geocoder.geocode(this.address)
    // console.log(loc)
    this.location = {
        type: 'Point',
        coordinates: [loc[0].longitude, loc[0].latitude],
        formattedAddress: loc[0].formattedAddress
    }

    // Do not save address
    this.address = undefined
    next()
})

module.exports = mongoose.model('Home', HomeSchema)

请求处理控制器 #

exports.addHome = async (req, res, next) => {
    try {
    //    console.log(req.body)
    const home = await Home.create(req.body)
    return res.status(201).json({
        success: true,
        data: home
    })
    } catch (error) {
        console.error(error)
        if(error.code === 11000) {
            return res.status(400).json({ error: 'This home already exists.'})
        }
        res.status(500).json({error: 'Server error here!'})
    }
}

这个错误本质是请求体被重复读取导致的。node-geocoder默认的HTTP请求实现会复用请求对象，而HTTP请求体只能被消费一次。当单例的geocoder实例被多次调用时，之前的请求对象被重复使用，就会触发body used already错误。

方案1：自定义fetch实现，避免请求对象复用 #

安装node-fetch依赖：

npm install node-fetch

修改geoCoder.js，添加自定义fetch逻辑，确保每次请求都创建独立的请求配置：

const NodeGeocoder = require('node-geocoder');
const fetch = require('node-fetch');

const options = {
  provider: process.env.GEOCODER_PROVIDER,
  // 自定义fetch，每次请求传递全新的配置对象
  fetch: (url, opts) => fetch(url, { ...opts }),
  httpAdapter: 'https',
  apiKey: process.env.GEOCODER_API_KEY,
  formatter: null
};

const geocoder = NodeGeocoder(options);

module.exports = geocoder;

方案2：升级node-geocoder到最新版本 #

该问题可能是旧版本node-geocoder的bug，升级到最新版本大概率能解决：

npm update node-geocoder

方案3：临时方案——每次请求创建新的geocoder实例（不推荐，影响性能） #

如果上述方案无效，可以在pre('save')钩子中每次创建新的geocoder实例，避免单例复用：

// 修改HomeSchema中的pre钩子
HomeSchema.pre('save', async function(next) {
    const NodeGeocoder = require('node-geocoder');
    const geocoder = NodeGeocoder({
        provider: process.env.GEOCODER_PROVIDER,
        httpAdapter: 'https',
        apiKey: process.env.GEOCODER_API_KEY,
        formatter: null
    });
    const loc = await geocoder.geocode(this.address)
    this.location = {
        type: 'Point',
        coordinates: [loc[0].longitude, loc[0].latitude],
        formattedAddress: loc[0].formattedAddress
    }
    this.address = undefined
    next()
})

内容的提问来源于stack exchange，提问作者aquile hollins