For use with >= 2.0

archivechannel.js

var Discord = require('discord.io');
var fs = require('fs');

var client = new Discord.Client({
    token: "",
    autorun: true
});

var channelToArchive = "",
    channelToPost = ""

client.on('ready', function() {
    archive(client, channelToArchive, channelToPost);
});

//Would be more easier on RAM to use an IOStream, but at what cost, really?
function archive(client, cta, ctp) {
    var ctaData, ctpData, offset, mData;
    if (!client.channels[cta] || !client.channels[ctp]) return;

    ctaData = client.channels[cta];
    ctpData = client.channels[ctp];

    console.log("Starting archiver for: #%s", ctaData.name);
    console.log("Posting to: #%s", ctpData.name);

    try {
        mData = require('./' + ctaData.name + '.json');
        offset = mData[0].id;
    } catch(e) { mData = []; }
    
    return getMessages(client, ctaData, ctpData, offset, mData);
}

function getMessages(client, archiveChannel, postChannel, offset, heldMessages) {
    var opts = {
        channelID: archiveChannel.id,
        limit: 100
    };
    if (offset) opts.before = offset;

    client.getMessages(opts, function(err, messageArray) {
        if (err) return setTimeout( getMessages, 5000, client, archiveChannel, postChannel, offset, heldMessages, console.log("Receiving again in 5 seconds...") );
        if (!messageArray[0]) return uploadAndExit(postChannel.id, archiveChannel.name);

        console.log("Adding %d more messages", messageArray.length);
        appendAndSave(heldMessages, messageArray, archiveChannel.name);
        return setTimeout( getMessages, 500, client, archiveChannel, postChannel, messageArray[messageArray.length - 1].id, heldMessages);
    });
}

function appendAndSave(heldMessages, newMessages, channelName) {
    for (var i=0; i<newMessages.length; i++) {
        heldMessages.unshift( newMessages[i] );
    }
    return fs.writeFileSync('./' + channelName + '.json', JSON.stringify(heldMessages, null, '\t'));
}

function uploadAndExit(channelID, channelName) {
    var m = codeify(
        [
            ["Name: " + channelName],
            ["Archived: " + new Date().toUTCString()]
        ].join("\n"),
        'xl'
    );
    client.uploadFile({
        to: channelID,
        file: './' + channelName + '.json',
        message: m
    }, function(err) {
        if (err) return setTimeout( uploadAndExit, 5000, channelID, channelName, console.log(err), console.log("Uploading again in 5 seconds...") );
        process.exit(0);
    });
}

function codeify(m, as) {
	return "\`\`\`" + (as||"") + "\n" + m +"\n\`\`\`";
}