README.md



broken-link-checker   


Find broken links, missing images, etc in your HTML.


Features:


Parses local and remote HTML documents
Supports various HTML tags/attributes, not just <a href>

Supports redirects, absolute URLs, relative URLs and <base>

Provides detailed information about each link (HTTP and HTML)
URL keyword filtering with wildcards
Pause/Resume at any time


var blc = require("broken-link-checker");

var html = '<a href="https://google.com">absolute link</a>';
html += '<a href="/path/to/resource.html">relative link</a>';
html += '<img src="http://fakeurl.com/image.png" alt="missing image"/>';

var htmlChecker = new blc.HtmlChecker(null, {
    link: function(result) {
        console.log(result.html.index, result.broken, result.html.text, result.url.resolved);
        //-> 0 false "absolute link" "https://google.com/"
        //-> 1 false "relative link" "https://mywebsite.com/path/to/resource.html"
        //-> 2 true null "http://fakeurl.com/image.png"
    },
    complete: function() {
        console.log("done checking!");
    }
});

htmlChecker.scan(html, "https://mywebsite.com");


Installation

Node.js ~0.10 is required. There're two ways to use it:


Command Line Usage

To install, type this at the command line:

npm install broken-link-checker -g


After that, check out the help for available options:

blc -?


Programmatic API

To install, type this at the command line:

npm install broken-link-checker --save-dev


The rest of this document will assist you with how to use the API.


Classes


blc.HtmlChecker(options, handlers)

Scans an HTML string to find broken links.


handlers.link is fired with the result of each discovered link (broken or not).

handlers.junk is fired with the result of each skipped, as configured in options.
handlers.complete is fired after the last result or zero results.
.clearCache() will remove any cached URL responses. This is only relevant if the cacheResponses option is enabled.
.numActive() returns the number of active requests.
.pause() will pause the internal link queue, but will not pause any active requests.
.resume() will resume the internal link queue.

.scan(htmlString, baseUrl) parses & scans a single string. Returns false when there is a previously incomplete scan (and true otherwise).


baseUrl is the address to which all relative URLs will be made absolute. Without a value, links to relative URLs will output an "Invalid URL" error.


var htmlChecker = new blc.HtmlChecker(options, {
    link: function(result){},
    junk: function(result){},
    complete: function(){}
});

htmlChecker.scan(htmlString, baseUrl);


blc.HtmlUrlChecker(options, handlers)

Scans the HTML content at each queued URL to find broken links.


handlers.link is fired with the result of each discovered link (broken or not) within the current queue item.

handlers.junk is fired with the result of each skipped, as configured in options.

handlers.item is fired after a queue item's last result, on zero results, or if the HTML could not be retreived.
handlers.end is fired when the end of the queue has been reached.
.clearCache() will remove any cached URL responses. This is only relevant if the cacheResponses option is enabled.
.dequeue(id) removes an item from the queue. Returns true on success or an Error on failure.

.enqueue(htmlUrl, customData) adds an item to the queue. Items are auto-dequeued when their requests are complete. Returns a queue ID on success or an Error on failure.


customData is optional data that is stored in the queue item.


.length() returns the number of items in the queue.
.numActiveItems() returns the number of active HTML URL sessions (series of link requests).
.numActiveLinks() returns the number of active link requests.
.pause() will pause the queue, but will not pause any active requests.
.resume() will resume the queue.


var htmlUrlChecker = new blc.HtmlUrlChecker(options, {
    link: function(result, customData){},
    junk: function(result, customData){},
    item: function(error, htmlUrl, customData){},
    end: function(){}
});

htmlUrlChecker.enqueue(htmlUrl, customData);


blc.UrlChecker(options, handlers)

Requests each queued URL to determine if they are broken.


handlers.link is fired for each result (broken or not).
handlers.end is fired when the end of the queue has been reached.
.clearCache() will remove any cached URL responses. This is only relevant if the cacheResponses option is enabled.
.dequeue(id) removes an item from the queue. Returns true on success or an Error on failure.

.enqueue(url, baseUrl, customData) adds an item to the queue. Items are auto-dequeued when their requests are completed. Returns a queue ID on success or an Error on failure.


baseUrl is the address to which all relative URLs will be made absolute. Without a value, links to relative URLs will output an "Invalid URL" error.

customData is optional data that is stored in the queue item.


.length() returns the number of items in the queue.
.numActive() returns the number of active requests.
.pause() will pause the queue, but will not pause any active requests.
.resume() will resume the queue.


var urlChecker = new blc.UrlChecker(options, {
    link: function(result, customData){},
    end: function(){}
});

urlChecker.enqueue(url, baseUrl, customData);


Options


options.acceptedSchemes

Type: Array

Default value: ["http","https"]

Will only check links with schemes/protocols mentioned in this list. Any others (except those in excludedSchemes) will output an "Invalid URL" error.


options.cacheExpiryTime

Type: Number

Default Value: 3600000 (1 hour)

The number of milliseconds in which a cached response should be considered valid. This is only relevant if the cacheResponses option is enabled.


options.cacheResponses

Type: Boolean

Default Value: false

URL request results will be cached when true. This will ensure that each unique URL will only be checked once.


options.excludedKeywords

Type: Array

Default value: []

Will not check or output links that match the keywords and glob patterns in this list. The only wildcard supported is "*".

This option only applies to HtmlChecker and HtmlUrlChecker.


options.excludedSchemes

Type: Array

Default value: ["data","geo","javascript","mailto","sms","tel"]

Will not check or output links with schemes/protocols mentioned in this list. This avoids the output of "Invalid URL" errors with links that cannot be checked.

This option only applies to HtmlChecker and HtmlUrlChecker.


options.excludeExternalLinks

Type: Boolean

Default value: false

Will not check or output external links when true; relative links with a remote <base> included.

This option only applies to HtmlChecker and HtmlUrlChecker.


options.excludeInternalLinks

Type: Boolean

Default value: false

Will not check or output internal links when true.

This option only applies to HtmlChecker and HtmlUrlChecker.


options.excludeLinksToSamePage

Type: Boolean

Default value: true

Will not check or output links to the same page; relative and absolute fragments/hashes included.

This option only applies to HtmlChecker and HtmlUrlChecker.


options.excludeResponseData

Type: Boolean

Default value: true

Each link's lengthy response data will not be outputted when true.


options.filterLevel

Type: Number

Default value: 1

The tags and attributes that are considered links for checking, split into the following levels:


0: clickable links

1: clickable links, media

2: clickable links, media, stylesheets, scripts, forms

3: clickable links, media, stylesheets, scripts, forms, meta


To see the exact breakdown, check out the tag map. <base> is not listed because it is not a link, though it is always parsed.

This option only applies to HtmlChecker and HtmlUrlChecker.


options.maxSockets

Type: Number

Default value: Infinity

The maximum number of links to check at any given time.


options.maxSocketsPerHost

Type: Number

Default value: 1

The maximum number of links per host/port to check at any given time. This avoids overloading a single target host with too many concurrent requests. This will not limit concurrent requests to other hosts.


options.rateLimit

Type: Number

Default value: 0

The number of milliseconds to wait before each request.


options.requestMethod

Type: String

Default value: "head"

The HTTP request method used in checking links. Some sites do not respond correctly to "head", while "get" can provide more consistent and accurate results, albeit slower.


Handling link errors

Each result will have its own error key for which you can compare against:

if (result.error !== null) {
    // Server denied access
    if (result.error.code === "ECONNREFUSED"){}
    // Server could not be reached
    if (result.error.code === "ENOTFOUND"){}
    // Connection timed out
    if (result.error.code === "ETIMEDOUT"){}
    // Duh.
    if (result.error.message === "Invalid URL"){}
}


Roadmap Features


add ability to pass response from HtmlUrlChecker to UrlChecker to avoid requesting that URL twice
start/end string locations for URL attribute values (parse5#43)
change order of checking to: tcp error, 4xx code (broken), 5xx code (undetermined), 200
option to scrape response.body for erroneous sounding text (since an error page could be presented but still have code 200)
option to check broken link on archive.org for archived version (using this lib)
option to include iframe HTML source in checking?
option to run HtmlUrlChecker checks on page load (using jsdom) to include links added with JavaScript
option to check if hashes exist in target url document?
add throttle profiles (0–9, -1 for "custom") for easy configuring
check ftp:, sftp: (for downloadable files)
check mailto:, news:, nntp:, telnet:?
check local files if URL is relative and has no base URL?
full-site checker/crawler (honoring robots.txt, same-domain and optional same-subdomain)
cli non-tty mode -- change nesting ascii artwork to time stamps?
use ineed?
stream HTML files (parse5#26)

MarkdownChecker,MarkdownUrlChecker,HtmlMarkdownChecker,HtmlMarkdownUrlChecker


Changelog


0.6.5


handlers added: junk

linkObj added: excluded

CLI options removed: --include-same

CLI --verbose is now more verbose


0.6.4


options added: excludedKeywords

CLI options added: --exclude


0.6.3


linkObj added: http.cached

CLI options added: --verbose, --version

CLI options removed: --uncached


0.6.2


options added: cacheExpiryTime

reduced redundant URLs in cache


0.6.1


options added: requestMethod

CLI options added: --get


0.6.0


methods added: clearCache()

options added: cacheResponses

CLI options added: --filter-level, --ordered, --uncached


"javascript:" links now excluded


0.5.1 fun CLI spinner
0.5.0


API change
CLI options
options added: excludeExternalLinks, excludeResponseData, maxSockets

options renamed: maxSockets->maxSocketsPerHost

linkObj added: http

linkObj moved: response->http.response

linkObj changed: internal and samePage now compares the base URL (ignoring <base>) with links that may have <base> applied
switched from request to bhttp


0.4.3 added rateLimit option, cleanup
0.4.2 added url.redirected to linkObj, bug fixes
0.4.1


options added: acceptedSchemes, excludedSchemes, excludeInternalLinks, excludeLinksToSamePage

options removed: excludeEmptyAnchors

linkObj added: internal, samePage


0.4.0


checking HTML URLs now ignores options.base

linkObj added: html.selector


0.3.0


options added: maxSockets

options renamed: site->base


<base> supported
requesting links now only downloads the response header
faster test suite


0.2.2 added missing tags/attributes
0.2.1 basic CLI, bug fixes
0.2.0


options added: excludeEmptyAnchors, filterLevel

new linkObj structure
more complete test suite


0.1.0 initial release