我正在使用restify框架来构建一个小型应用，该应用将上传的文件从其临时位置复制到永久位置，然后将该新位置插入MySQL数据库。但是，当尝试复制文件然后运行承诺的查询时，系统会抛出一个未被诺言链捕获的静默错误，从而在Web服务器端造成502错误。下面是一个最小的工作示例。这个例子已经过测试，但确实失败了。
如果删除了过程中的步骤之一（复制文件或将字符串存储在数据库中，则静默错误消失，并发送API响应。但是，这两个步骤对于以后的文件检索都是必需的。
主要重新整理文件
const restify = require('restify');
const corsMiddleware = require('restify-cors-middleware');
const cookieParser = require('restify-cookies');
const DataBugsDbCredentials = require('./config/config').appdb;
const fs = require('fs');
const { host, port, name, user, pass } = DataBugsDbCredentials;
const database = new (require('./lib/database'))(host, port, name, user, pass);
const server = restify.createServer({
name: 'insect app'
});
// enable options response in restify (anger) -- this is so stupid!! (anger)
const cors = corsMiddleware({});
server.pre(cors.preflight);
server.use(cors.actual);
// set query and body parsing for access to this information on requests
server.use(restify.plugins.acceptParser(server.acceptable));
server.use(restify.plugins.queryParser({ mapParams: true }));
server.use(restify.plugins.bodyParser({ mapParams: true }));
server.use(cookieParser.parse);
server.post('/test', (req, res, next) => {
const { files } = req;
let temporaryFile = files['file'].path;
let permanentLocation = '/srv/www/domain.com/permanent_location';
// copy file
return fs.promises.copyFile(temporaryFile, permanentLocation)
// insert into database
.then(() => database.query(
`insert into Specimen (
CollectorId,
HumanReadableId,
FileLocation
) values (
1,
'AAA004',
${permanentLocation}
)`
))
.then(() => {
console.log('success!!!')
return res.send('success!')
})
.catch(error => {
console.error(error)
return res.send(error);
});
});
./ lib / database.js
'use strict';
const mysql = require('mysql2');
class Database {
constructor(host, port, name, user, pass) {
this.connection = this.connect(host, port, name, user, pass);
this.query = this.query.bind(this);
}
/**
* Connects to a MySQL-compatible database, returning the connection object for later use
* @param {String} host The host of the database connection
* @param {Number} port The port for connecting to the database
* @param {String} name The name of the database to connect to
* @param {String} user The user name for the database
* @param {String} pass The password for the database user
* @return {Object} The database connection object
*/
connect(host, port, name, user, pass) {
let connection = mysql.createPool({
connectionLimit : 20,
host : host,
port : port,
user : user,
password : pass,
database : name,
// debug : true
});
connection.on('error', err => console.error(err));
return connection;
}
/**
* Promisifies database queries for easier handling
* @param {String} queryString String representing a database query
* @return {Promise} The results of the query
*/
query(queryString) {
// console.log('querying database');
return new Promise((resolve, reject) => {
// console.log('query promise before query, resolve', resolve);
// console.log('query promise before query, reject', reject);
// console.log('query string:', queryString)
this.connection.query(queryString, (error, results, fields) => {
console.log('query callback', queryString);
console.error('query error', error, queryString);
if (error) {
// console.error('query error', error);
reject(error);
} else {
// console.log('query results', results);
resolve(results);
}
});
});
}
}
module.exports = Database;
./ testfile.js（用于快速查询restify API）
'use strict';
const fs = require('fs');
const request = require('request');
let req = request.post({
url: 'https://api.databugs.net/test',
}, (error, res, addInsectBody) => {
if (error) {
console.error(error);
} else {
console.log('addInsectBody:', addInsectBody);
}
});
let form = req.form();
form.append('file', fs.createReadStream('butterfly.jpg'), {
filename: 'butterfly.jpg',
contentType: 'multipart/form-data'
});
如果向本地主机发出请求，则抛出“ ECONNRESET”错误，如下所示：
Error: socket hang up
at connResetException (internal/errors.js:570:14)
at Socket.socketOnEnd (_http_client.js:440:23)
at Socket.emit (events.js:215:7)
at endReadableNT (_stream_readable.js:1183:12)
at processTicksAndRejections (internal/process/task_queues.js:80:21) {
code: 'ECONNRESET'
}
仅当promise链中同时存在数据库和文件I / O时，才会引发此错误。此外，如果首先发出数据库请求而第二次发生文件I / O，则不会发生该错误；但是，对服务器的另一个快速请求将立即导致“ ECONNRESET”错误。
到目前为止，我发现的唯一解决方案是切换文件I / O和数据库查询，以便最后执行文件I / O操作。此外，将文件I / O操作更改为重命名而不是复制文件可防止连续的API查询快速抛出相同的错误（在进行任何非重命名的文件I / O操作之后迅速进行数据库查询） ）。不幸的是，我对OP中的套接字挂起没有合理的解释，但是下面是OP修改后的代码以使其正常运行。
const restify = require('restify');
const corsMiddleware = require('restify-cors-middleware');
const cookieParser = require('restify-cookies');
const DataBugsDbCredentials = require('./config/config').appdb;
const fs = require('fs');
const { host, port, name, user, pass } = DataBugsDbCredentials;
const database = new (require('./lib/database'))(host, port, name, user, pass);
const server = restify.createServer({
name: 'insect app'
});
// enable options response in restify (anger) -- this is so stupid!! (anger)
const cors = corsMiddleware({});
server.pre(cors.preflight);
server.use(cors.actual);
// set query and body parsing for access to this information on requests
server.use(restify.plugins.acceptParser(server.acceptable));
server.use(restify.plugins.queryParser({ mapParams: true }));
server.use(restify.plugins.bodyParser({ mapParams: true }));
server.use(cookieParser.parse);
server.post('/test', (req, res, next) => {
const { files } = req;
let temporaryFile = files['file'].path;
let permanentLocation = '/srv/www/domain.com/permanent_location';
// copy file
// insert into database
return database.query(
`insert into Specimen (
CollectorId,
HumanReadableId,
FileLocation
) values (
1,
'AAA004',
${permanentLocation}
)`
)
.then(() => fs.promises.rename(temporaryFile, permanentLocation))
.then(() => {
console.log('success!!!')
return res.send('success!')
})
.catch(error => {
console.error(error)
return res.send(error);
});
});
您当时没有处理数据库承诺并捕获-
主要重新整理文件
const restify = require('restify');
const corsMiddleware = require('restify-cors-middleware');
const cookieParser = require('restify-cookies');
const DataBugsDbCredentials = require('./config/config').appdb;
const fs = require('fs');
const { host, port, name, user, pass } = DataBugsDbCredentials;
const database = new (require('./lib/database'))(host, port, name, user, pass);
const server = restify.createServer({
name: 'insect app'
});
// enable options response in restify (anger) -- this is so stupid!! (anger)
const cors = corsMiddleware({});
server.pre(cors.preflight);
server.use(cors.actual);
// set query and body parsing for access to this information on requests
server.use(restify.plugins.acceptParser(server.acceptable));
server.use(restify.plugins.queryParser({ mapParams: true }));
server.use(restify.plugins.bodyParser({ mapParams: true }));
server.use(cookieParser.parse);
server.post('/test', (req, res, next) => {
const { files } = req;
let temporaryFile = files['file'].path;
let permanentLocation = '/srv/www/domain.com/permanent_location';
// copy file
return fs.promises.copyFile(temporaryFile, permanentLocation)
// insert into database
.then(() =>{
// Your database class instance query method returns promise
database.query(
`insert into Specimen (
CollectorId,
HumanReadableId,
FileLocation
) values (
1,
'AAA004',
${permanentLocation}
)`
).then(() => {
console.log('success!!!')
return res.send('success!')
})
.catch(error => {
console.error('Inner database promise error', error)
return res.send(error);
});
}).catch(error => {
console.error('Outer fs.copyfile promise error', error)
return res.send(error);
})
});