NodeJS 4chan image downloaderFirst attempt, downloads all images from a board. OUTDATED! SEE: https://github.com/j3lte/chanarchive

node4chan.js

//
// ******************************************************************
// THIS GIST IS OUTDATED. SEE : https://github.com/j3lte/chanarchive
// ******************************************************************

// URL Representation

/*
JSON representations of threads and indexes are exposed at the following URLs:
http(s)://api.4chan.org/board/res/threadnumber.json
http(s)://api.4chan.org/board/pagenumber.json (0 is main index)

A JSON representation of all thread OPs from an individual board can be found at the following URL:
http(s)://api.4chan.org/board/catalog.json

A list of boards is exposed at the following URL:
http(s)://api.4chan.org/boards.json
*/

// Vars
var  	path = require('path')
	,	fs = require('fs')
	,	request = require('request')
	,	mkdirp = require('mkdirp')
	,	saveFolder = './download/'
	,	numFiles = 0;

var thrd = process.argv[2],
	test = /^http:\/\/boards.4chan.org\/(\w){1,}\/res\/(\d){1,}/;

if (typeof(thrd) === 'undefined' || thrd === null || !test.test(thrd)){
	showUsage();
} else {

	console.log(thrd);

	var board = thrd.split(/\/|\?|&|=|\./g)[5],
		thrdnum = thrd.split(/\/|\?|&|=|\./g)[7];

	downloadBoard(board,thrdnum);
}


function showUsage(){
	console.log('Usage: node main.js http://boards.4chan.org/<board>/res/<thread>');
	process.exit(1);	
}

function downloadBoard(board,thread){

	var boardUrl = 'http://api.4chan.org/'+board+'/res/'+thread+'.json';

	request(boardUrl, function (error, response, body) {

		if (!error && response.statusCode == 200 && response.headers['content-type'] === 'application/json') {
			
			console.log("Downloaded: "+boardUrl);
			saveFolder += board+'/'+thrdnum+'/';

			mkdirp(saveFolder, function(err){
				if (err) {
					console.error('Error creating folder! '+err);
				} else {
					console.log('Files saved in: ' + saveFolder);
					var jsonBody = JSON.parse(body);

					fs.writeFile(saveFolder+thread+'.json.txt',JSON.stringify(jsonBody,null,4));

					jsonBody.posts.forEach(
						
						function(post){
							
							if (post.filename){
								numFiles++;
								
								var orig = post.filename+'_'+post.tim+post.ext,
									ren = 'http://images.4chan.org/'+board+'/src/'+post.tim+post.ext;
								
								downloadPic(ren,orig);
							}					
						}
					);
				} 
			});
		} else {
			console.log("Not found! Tried: "+boardUrl);
		}
	}); 
}

// Download
function downloadPic (urlPic,orig){
	
	var localPath = saveFolder+orig;
	var r = request(urlPic).pipe(fs.createWriteStream(localPath));

	r.on('close',function(){
		numFiles--;
		console.log('Downloaded ' + localPath + ' [ ' + numFiles + ' remaining ]');
	});
	r.on('error',function(){
		numFiles--;
		console.log('Error downloading ' + localPath);
	});
};