用户的Nodejs CSV数据导出系统

本文介绍了用户的Nodejs CSV数据导出系统的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我需要允许用户以csv格式导出其数据.我已经在nodejs中编写了应用程序.用户的导出数据可能非常庞大.所以我想知道如何在nodejs中处理这种情况.我应该使用node.js的process.nexttick还是子进程api?还有一些好模块可用于nodejs将数据从mysql转换为csv.

I need to allow users to export their data in csv format. I have written app in nodejs. The export data for users can be huge. So i was wondering How to handle such situation in nodejs. Should i user process.nexttick or child process api of nodejs? Also are there any good module available for nodejs to convert data from mysql to csv.

推荐答案

从mysql-db逐行读取，并将行逐行追加到文件中

read line by line from your mysql-db, and append line by line to your file

我对mysqlmodule不太了解，所以我假设这里每一行只是一个数组，因此是'row.join(';')'.如果不是这种情况(也许它是一个对象)，则应修复该问题.

i dont know that much about the mysqlmodule, so i'm assuming here each line is just an array, therefore the 'row.join(';')'. if thats not the case (maybe its an object), you should fix that.

var fs = require('fs');
var connection = require('mysql').createConnection({yourdbsettingshere});

function processRow (row) {
  fs.appendFile('your-file.csv', row.join(';'), function (err) {
    connection.resume();
  });
}

var query = connection.query('SELECT * FROM WHATEVER');

query
  .on('error', function(err) {
    // do something when an error happens
  })
 .on('fields', function(fields) {
   processRow(fields);
 })
 .on('result', function(row) {
   // Pausing the connnection is useful if your processing involves I/O
   connection.pause();
   processRow(row, function (err) {
     connection.resume();
   });
 })
 .on('end', function() {
    // now you can mail your user
 });

如果您有很多请求，则可以使用计算群集模块进行分发您的工作量

if you have a lot of requests, you could use the compute-cluster module for distributing your workload

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NodeJS