how to save an image from discord using discord bot node js

问题

So far I've only been able to get text and links from what other people on my discord channel type, but I want to be able to save posted images/gifs. is there any way I can do this through the bot or is it impossible? I'm using discord.js.

回答1:

Images in Discord.js come in the form of MessageAttachments via Message#attachments. By looping through the amount of attachments, we can retrieve the raw file via MessageAttachment#attachment and the file type using MessageAttachment#name. Then, we use node's FileSystem to write the file onto the system. Here's a quick example. This example assumes you already have the message event and the message variable.

const fs = require('fs');
msg.attachments.forEach(a => {
    fs.writeFileSync(`./${a.name}`, a.file); // Write the file to the system synchronously.
});

Please note that in a real world scenario you should surround the synchronous function with a try/catch statement, for errors.

Also note that, according to the docs, the attachment can be a stream. I have yet to have this happen in the real world, but if it does it might be worth checking if a is typeof Stream, and then using fs.createWriteStream and piping the file into it.

来源：https://stackoverflow.com/questions/49063287/how-to-save-an-image-from-discord-using-discord-bot-node-js