robots.js
robots.js — is parser for robots.txt files for node.js.
Installation
It's recommended to install via npm:
$ npm install -g robotsUsage
Here's an example of using robots.js:
var robots = require('robots')
, parser = new robots.RobotsParser();
parser.setUrl('http://nodeguide.ru/robots.txt', function(parser, success) {
if(success) {
parser.canFetch('*', '/doc/dailyjs-nodepad/', function (access) {
if (access) {
// parse url
}
});
}
});Default crawler user-agent is:
Mozilla/5.0 (X11; Linux i686; rv:5.0) Gecko/20100101 Firefox/5.0
Here's an example of using another user-agent and more detailed callback:
var robots = require('robots')
, parser = new robots.RobotsParser(
'http://nodeguide.ru/robots.txt',
'Mozilla/5.0 (compatible; RobotTxtBot/1.0)',
after_parse
);
function after_parse(parser, success) {
if(success) {
parser.canFetch('*', '/doc/dailyjs-nodepad/', function (access, url, reason) {
if (access) {
console.log(' url: '+url+', access: '+access);
// parse url ...
}
});
}
};Here's an example of getting list of sitemaps:
var robots = require('robots')
, parser = new robots.RobotsParser();
parser.setUrl('http://nodeguide.ru/robots.txt', function(parser, success) {
if(success) {
parser.getSitemaps(function(sitemaps) {
// sitemaps — array
});
}
});Here's an example of getCrawlDelay usage:
var robots = require('robots')
, parser = new robots.RobotsParser();
// for example:
//
// $ curl -s http://nodeguide.ru/robots.txt
//
// User-agent: Google-bot
// Disallow: /
// Crawl-delay: 2
//
// User-agent: *
// Disallow: /
// Crawl-delay: 2
parser.setUrl('http://nodeguide.ru/robots.txt', function(parser, success) {
if(success) {
var GoogleBotDelay = parser.getCrawlDelay("Google-bot");
// ...
}
});An example of passing options to the HTTP request:
var options = {
headers:{
Authorization:"Basic " + new Buffer("username:password").toString("base64")}
}
var robots = require('robots')
, parser = new robots.RobotsParser(null, options);
parser.setUrl('http://nodeguide.ru/robots.txt', function(parser, success) {
...
});API
RobotsParser — main class. This class provides a set of methods to read, parse and answer questions about a single robots.txt file.
- setUrl(url, read) — sets the URL referring to a robots.txt file. by default, invokes read() method. If read is a function, it is called once the remote file is downloaded and parsed, and it takes in two arguments: the first is the parser itself, and the second is a boolean which is True if the the remote file was successfully parsed.
- read(after_parse) — reads the robots.txt URL and feeds it to the parser
- parse(lines) — parse the input lines from a robots.txt file
- canFetch(userAgent, url, callback) — using the parsed robots.txt decide if
userAgent can fetch url. Callback function:
function callback(access, url, reason) { ... }where:- access — can this url be fetched. true/false.
- url — target url
- reason — reason for
access. Object:- type — valid values: 'statusCode', 'entry', 'defaultEntry', 'noRule'
- entry — an instance of
lib/Entry.js:. Only for types: 'entry', 'defaultEntry' - statusCode — http response status code for url. Only for type 'statusCode'
- canFetchSync(userAgent, url) — using the parsed robots.txt decide if userAgent can fetch url. Return true/false.
- getCrawlDelay(userAgent) — returns Crawl-delay for the certain userAgent
- getSitemaps(sitemaps) — gets Sitemaps from parsed robots.txt
- getDisallowedPaths(userAgent) — gets paths explictly disallowed for the user agent specified AND *
License
See LICENSE file.