## Introduction
Webcheck gives you an infrastructure to analyze web resources. It is build very generic for supporting a wide range of
possible use cases. You are able to analyze a single page, a whole domain or even everything connected to one or more
seed resources. You can analyze every content-type.

Version 1.0.0 is refactored completely. Webcheck uses streams. Because of the streams it uses plugins instead of
middleware. There is a [list of plugins](https://github.com/atd-schubert/node-webcheck/blob/master/PLUGINS.md)
in the github repository. Please send me the link to yours if you develop one. Otherwise you should look on
[npm](https://www.npmjs.com/) for modules with prefix 'webcheck-'.

## How to use

### Installation

```bash
npm install webcheck
```

### Use in node.js

```js
var { Webcheck } = require('webcheck');
var AnyPlugin = require('webcheck-any-plugin');

var webcheck = new Webcheck();
var anyPlugin = new AnyPlugin({your: 'options'});
webcheck.addPlugin(anyPlugin);

anyPlugin.enable();

webcheck.crawl({
    url: 'http://some.website/url'
}, function (err) {
    if (err) {
        console.error('There was an error while crawling', err);
    }
    console.log('Crawling done...');
});
```

## Concept of this module
Since version 1.0.0 webcheck uses streams instead of callbacks. It is not compatible to older versions!

Webcheck is small featured. You should extend your functionality with plugins. Take a look at the
[list of plugins](https://github.com/atd-schubert/node-webcheck/blob/master/PLUGINS.md).

## Plugins

For further information about plugins in webcheck take a look at the [plugin readme](PLUGINS.md).

## Webcheck Class
### Methods of webcheck
#### webcheck.addPlugin(plugin)

Add a plugin to webcheck.

#### webcheck.crawl(settings, callback)

Request a resource

##### List of settings

* `url | {string}` [mandatory]: URL to crawl
* `wait | {Number}`: Time to wait till request (default: 0)
* `headers | {Object}`: Default headers (default: {"User-Agent": "webcheck v1.0.0"})
* `request | {request}`: The used request-module
* `immediately | {boolean}`: Should the crawl push as next one to queue.
* `parameters | {Object}`: A object to pass parameters to other plugins about this crawl

### Properties of webcheck

#### webcheck.request

This is a instance of [request](https://github.com/request/request). Webcheck use this as function to request a
resource. If you want another request function, for example to request resources from TOR with
[torrequest](https://github.com/atd-schubert/torrequest), you are able to swap this property.

#### webcheck.middlewares

Array of used middleware.

### Events of webcheck

All events emitted on the webcheck object.

    var webcheck = new Webcheck();
    webcheck.on(event, fn);

Webcheck emits the following events:

- `crawl` (request-settings): Emitted directly after calling crawl method.
- `request` (request-settings): Emitted before request is executed.
- `result` ({url, request-settings, request, response}): Emitted after middleware are executed and document is fetched
- `drain`: Emitted on draining of queue
- `queue` (request-settings): Emitted before adding to queue
- `addPlugin` (plugin): Emitted when a plugin is added
- `enablePlugin` (plugin): Emitted when a added plugin gets enabled
- `disablePlugin` (plugin): Emitted when a added plugin gets disabled

## Changes on version 1.1.0 and 2.0.0
From now on Webcheck is a class within the module webcheck.

That means Webcheck **must now** required over:

```ts
import { Webcheck, Plugin } from 'webcheck';
```

or in the classical way:

```js
var Webcheck = require('webcheck').Webcheck;
```

It is no longer possible to require Webcheck the old way! That could also cause incompatibilities with older Plugins.