javascript - 如何在 Feathers 中创建异步超时错误处理程序？

Question

如何创建一个异步函数超时错误处理程序作为驻留在服务文件中的 Feather 中的钩子(Hook)来处理钩子(Hook)中的 Promise？

按照@Bergi on my previous question的建议专门创建的帖子

If you are looking to implement a generic async-function timeout (for promises failing to fulfill for whatever reason) as a featherjs hook, you might want to ask a new (different!) question about specifically that.

我需要一个将添加到database.hooks.js的函数文件(如示例文档中的错误处理程序)将处理由类似于 get-database-by-id.js 的钩子(Hook)引起的异常(导致超时)，而无需更改 get-database-by-id.js 中的代码:

按 id 获取数据库

const errors = require('@feathersjs/errors');

module.exports = function (options = {}) {
  return async context => {
    let promise = new Promise((resolve,reject) => { 
                    context.app.service('database').find({
                query: {"id":context.data.id}
                }).then(result => {

                      resolve(result.data[0].data)
                                           // console: error: Unhandled Rejection at: Promise 
                                           //browser:  hangs

            });
    });
    let result = await promise;
    if (result) {
        return context;
    }

  };
};

database.hooks.js(使用文档中的错误处理程序示例，不适用于 Promise)

const { authenticate } = require('@feathersjs/authentication').hooks;

const getDatabaseById = require('../../hooks/get-database-by-id');

const errors = require('@feathersjs/errors');

const errorHandler = ctx => {
  if (ctx.error) {
    const error = ctx.error;
    if (!error.code) {
      const newError = new errors.GeneralError("server error");
      ctx.error = newError;
      return ctx;
    }
    if (error.code === 404 || process.env.NODE_ENV === "production") {
      error.stack = null;
    }
    return ctx;
  }
};


module.exports = {
  before: {
    all: [ authenticate('jwt')],
    find: [],
    get: [],
    create: [
      getDatabaseById,
    ],
    update: [],
    patch: [],
    remove: []
  },

  after: {
    all: [],
    find: [],
    get: [],
    create: [],
    update: [],
    patch: [],
    remove: []
  },

  error: {
    all: [errorHandler],
    find: [],
    get: [],
    create: [],
    update: [],
    patch: [],
    remove: []
  }
};

Answer 1

如果featherjs find返回一个promise，那么就没有必要将它包装成一个。

但我认为我理解这个问题的意思是，featherjs 已损坏，因为它不会拒绝或解决丢失的 id，并且您希望在合理的等待时间后强制解决。如果我理解正确的话，您可以使用 Promise.race() 实现自己的超时

// find with the given id, or reject after quitAfter milliseconds
async function findById(id, quitAfter) {
  let timer = new Promise(function(resolve, reject) {
    setTimeout(reject, quitAfter, 'timeout exceeded');
  });
  let query = context.app.service('database').find({
    query: { "id": id }
  });
  return Promise.race([timer, query]);
}