javascript - 为什么我的程序在管理这个 JSON 文件时会崩溃？

Question

每当有人发送!setmainchannel时，我的程序就会崩溃。我正在使用带有包 discord.js 的 Node.js。这是我唯一的问题。我不明白也不明白出了什么问题，如果有人能帮助我，我将不胜感激。

bot.js：

let Discord = require("discord.js");
let client = new Discord.Client();
let fs = require('fs');

let help = require("./helpembed.json");

var jsonRead = function(filePath){
  fs.readFile(filePath, 'utf-8', (err, returnJson) => {
    if(err){
      console.log(err);
    }
    else{
      let ret = JSON.parse(returnJson);
      return ret;
    }
  })
}

var jsonWrite = function(filePath, objIn){
  fs.writeFile(filePath, JSON.stringify(objIn), err => {
    if(err){
      console.log(err);
    }
  })
}

client.on("message", msg => {
  let time = new Date();
  let cstTimeStamp = `${time.getMonth() + 1}/${time.getDate()}/${time.getFullYear()} ${time.getHours() + 1}:${time.getMinutes()}:${time.getSeconds()}`

  if(msg.content == "!setmainchannel"){
    let mainChannel = msg.mentions.channels.first();

    if(!mainChannel){
      console.log(`${cstTimeStamp} @${msg.author.tag} requested to set a main channel but didn't provide a channel\n`);
      msg.channel.send("There's no channel to set the main to");
    }
    else{
      let currentSettings = jsonRead("./main-channel.json");
      currentSettings.channel = mainChannel;
      jsonWrite("./main-channel.json", currentSettings);
      console.log(`${cstTimeStamp} @${msg.author.tag} set the main channel as ${currentSettings.channel}\n`);
      msg.channel.send(`Set the main channel as ${currentSettings.channel}`);
    }
    
  }
})

client.once('ready', () => {
    console.log('Bot is online\n');
});

client.login('Token hidden for safety reasons');

main-channel.json：

{
    "channel":null
}

标签： javascriptnode.jsjsondiscord.js

Answer 1

首先，您的机器人什么都不做，因为它只会做出反应if (msg.content == "!setmainchannel")。如果您提供参数，例如通道 ( !setmainchannel #ch-name)，它将不会运行，因为消息的内容不完全是前缀和命令。

你需要先解决这个问题。通过删除前缀并切掉参数，您可以获得命令本身并检查是否使用了这个确切的命令。（同样，你不应该检查整个message.content）

其次，您不必等待内部的回调readFile运行。这意味着，当您尝试更新时currentSettings.channel，您的jsonRead()函数刚刚开始读取文件并且currentSettings是undefined. 您将无法更新其channel属性。

我已经更新了您的jsonWrite和jsonRead函数以返回承诺并使其更易于使用。检查下面的工作代码：

const Discord = require("discord.js");
const fs = require('fs');
const path = require('path');

const client = new Discord.Client();
const prefix = '!';

client.on('message', async (msg) => {
  // create an args variable that slices off the prefix and splits it into an array
  const args = msg.content.slice(prefix.length).split(/ +/);
  // create a command variable by taking the first element in the array
  // and removing it from args
  const command = args.shift().toLowerCase();
  const cstTimeStamp = new Date().toLocaleString();

  if (command === 'setmainchannel') {
    const mainChannel = msg.mentions.channels.first();
    const filePath = path.resolve(__dirname, './main-channel.json');

    if (!mainChannel) {
      console.log(`${cstTimeStamp} ${msg.author.tag} requested to set a main channel but didn't provide a channel\n`);
      return msg.channel.send("There's no channel to set the main to");
    }

    try {
      const currentSettings = await jsonRead(filePath);
      currentSettings.channel = mainChannel;

      jsonWrite(filePath, currentSettings);

      console.log(`${cstTimeStamp} ${msg.author.tag} set the main channel as ${currentSettings.channel}\n`);
      msg.channel.send(`Set the main channel as ${currentSettings.channel}`);
    } catch (err) {
      console.log(err);
    }
  }
});

client.once('ready', () => {
    console.log('Bot is online\n');
});

client.login('Token hidden for safety reasons');

function jsonRead(filePath) {
  return new Promise((resolve, reject) => {
    fs.readFile(filePath, 'utf-8', (err, content) => {
      if (err) {
        reject(err);
      } else {
        try {
          const parsedContent = JSON.parse(content);
          resolve(parsedContent);
        } catch (err) {
          reject(err);
        }
      }
    });
  });
}

function jsonWrite(filePath, data) {
  return new Promise((resolve, reject) => {
    fs.writeFile(filePath, JSON.stringify(data), (err) => {
      if (err) {
        reject(err);
      }
      resolve(true);
    });
  });
}