- Notifications
You must be signed in to change notification settings - Fork1.4k
WebCollector is an open source web crawler framework based on Java.It provides some simple interfaces for crawling the Web,you can setup a multi-threaded web crawler in less than 5 minutes.
License
CrawlScript/WebCollector
Folders and files
| Name | Name | Last commit message | Last commit date | |
|---|---|---|---|---|
Repository files navigation
WebCollector is an open source web crawler framework based on Java.It providessome simple interfaces for crawling the Web,you can setup amulti-threaded web crawler in less than 5 minutes.
In addition to a general crawler framework, WebCollector also integratesCEPF, a well-designed state-of-the-art web content extraction algorithm proposed by Wu, et al.:
- Wu GQ, Hu J, Li L, Xu ZH, Liu PC, Hu XG, Wu XD. Online Web news extraction via tag path feature fusion. Ruan Jian Xue Bao/Journal of Software, 2016,27(3):714-735 (in Chinese).http://www.jos.org.cn/1000-9825/4868.htm
https://github.com/CrawlScript/WebCollector
<dependency> <groupId>cn.edu.hfut.dmic.webcollector</groupId> <artifactId>WebCollector</artifactId> <version>2.73-alpha</version></dependency>
WebCollector jars are available on theHomePage.
- webcollector-version-bin.zip contains core jars.
Annotation versions are named withDemoAnnotatedxxxxxx.java.
- DemoAutoNewsCrawler.java |DemoAnnotatedAutoNewsCrawler.java
- DemoManualNewsCrawler.java |DemoAnnotatedManualNewsCrawler.java
- DemoExceptionCrawler.java
- DemoMetaCrawler.java
- DemoAnnotatedMatchTypeCrawler.java
- DemoAnnotatedDepthCrawler.java
- DemoBingCrawler.java |DemoAnnotatedBingCrawler.java
- DemoAnnotatedDepthCrawler.java
- DemoCookieCrawler.java
- DemoRedirectCrawler.java |DemoAnnotatedRedirectCrawler.java
- DemoPostCrawler.java
- DemoRandomProxyCrawler.java
- AbuyunDynamicProxyRequester.java
- DemoSeleniumCrawler.java
Lets crawl some news from github news.This demo prints out the titles and contents extracted from news of github news.
importcn.edu.hfut.dmic.webcollector.model.CrawlDatums;importcn.edu.hfut.dmic.webcollector.model.Page;importcn.edu.hfut.dmic.webcollector.plugin.rocks.BreadthCrawler;/** * Crawling news from github news * * @author hu */publicclassDemoAutoNewsCrawlerextendsBreadthCrawler {/** * @param crawlPath crawlPath is the path of the directory which maintains * information of this crawler * @param autoParse if autoParse is true,BreadthCrawler will auto extract * links which match regex rules from pag */publicDemoAutoNewsCrawler(StringcrawlPath,booleanautoParse) {super(crawlPath,autoParse);/*start pages*/this.addSeed("https://blog.github.com/");for(intpageIndex =2;pageIndex <=5;pageIndex++) {StringseedUrl =String.format("https://blog.github.com/page/%d/",pageIndex);this.addSeed(seedUrl); }/*fetch url like "https://blog.github.com/2018-07-13-graphql-for-octokit/" */this.addRegex("https://blog.github.com/[0-9]{4}-[0-9]{2}-[0-9]{2}-[^/]+/");/*do not fetch jpg|png|gif*///this.addRegex("-.*\\.(jpg|png|gif).*");/*do not fetch url contains #*///this.addRegex("-.*#.*");setThreads(50);getConf().setTopN(100);//enable resumable mode//setResumable(true); }@Overridepublicvoidvisit(Pagepage,CrawlDatumsnext) {Stringurl =page.url();/*if page is news page*/if (page.matchUrl("https://blog.github.com/[0-9]{4}-[0-9]{2}-[0-9]{2}[^/]+/")) {/*extract title and content of news by css selector*/Stringtitle =page.select("h1[class=lh-condensed]").first().text();Stringcontent =page.selectText("div.content.markdown-body");System.out.println("URL:\n" +url);System.out.println("title:\n" +title);System.out.println("content:\n" +content);/*If you want to add urls to crawl,add them to nextLink*//*WebCollector automatically filters links that have been fetched before*//*If autoParse is true and the link you add to nextLinks does not match the regex rules,the link will also been filtered.*///next.add("http://xxxxxx.com"); } }publicstaticvoidmain(String[]args)throwsException {DemoAutoNewsCrawlercrawler =newDemoAutoNewsCrawler("crawl",true);/*start crawl with depth of 4*/crawler.start(4); }}
importcn.edu.hfut.dmic.webcollector.model.CrawlDatums;importcn.edu.hfut.dmic.webcollector.model.Page;importcn.edu.hfut.dmic.webcollector.plugin.rocks.BreadthCrawler;/** * Crawling news from github news * * @author hu */publicclassDemoManualNewsCrawlerextendsBreadthCrawler {/** * @param crawlPath crawlPath is the path of the directory which maintains * information of this crawler * @param autoParse if autoParse is true,BreadthCrawler will auto extract * links which match regex rules from pag */publicDemoManualNewsCrawler(StringcrawlPath,booleanautoParse) {super(crawlPath,autoParse);// add 5 start pages and set their type to "list"//"list" is not a reserved word, you can use other string insteadthis.addSeedAndReturn("https://blog.github.com/").type("list");for(intpageIndex =2;pageIndex <=5;pageIndex++) {StringseedUrl =String.format("https://blog.github.com/page/%d/",pageIndex);this.addSeed(seedUrl,"list"); }setThreads(50);getConf().setTopN(100);//enable resumable mode//setResumable(true); }@Overridepublicvoidvisit(Pagepage,CrawlDatumsnext) {Stringurl =page.url();if (page.matchType("list")) {/*if type is "list"*//*detect content page by css selector and mark their types as "content"*/next.add(page.links("h1.lh-condensed>a")).type("content"); }elseif(page.matchType("content")) {/*if type is "content"*//*extract title and content of news by css selector*/Stringtitle =page.select("h1[class=lh-condensed]").first().text();Stringcontent =page.selectText("div.content.markdown-body");//read title_prefix and content_length_limit from configurationtitle =getConf().getString("title_prefix") +title;content =content.substring(0,getConf().getInteger("content_length_limit"));System.out.println("URL:\n" +url);System.out.println("title:\n" +title);System.out.println("content:\n" +content); } }publicstaticvoidmain(String[]args)throwsException {DemoManualNewsCrawlercrawler =newDemoManualNewsCrawler("crawl",false);crawler.getConf().setExecuteInterval(5000);crawler.getConf().set("title_prefix","PREFIX_");crawler.getConf().set("content_length_limit",20);/*start crawl with depth of 4*/crawler.start(4); }}
CrawlDatum is an important data structure in WebCollector, which corresponds to url of webpages. Both crawled urls and detected urls are maintained as CrawlDatums.
There are some differences between CrawlDatum and url:
- A CrawlDatum contains a key and a url. The key is the url by default. You can set the key manually by CrawlDatum.key("xxxxx") so that CrawlDatums with the same url may have different keys. This is very useful in some tasks like crawling data by api, which often request different data by the same url with different post parameters.
- A CrawlDatum may contain metadata, which could maintain some information besides the url.
In bothvoid visit(Page page, CrawlDatums next) andvoid execute(Page page, CrawlDatums next), the second parameterCrawlDatum next is a container which you should put the detected URLs in:
//add one detected URLnext.add("detected URL");//add one detected URL and set its typenext.add("detected URL","type");//add one detected URLnext.add(newCrawlDatum("detected URL"));//add detected URLsnext.add("detected URL list");//add detected URLsnext.add(("detected URL list","type");//add detected URLsnext.add(newCrawlDatums("detected URL list"));//add one detected URL and return the added URL(CrawlDatum)//and set its key and typenext.addAndReturn("detected URL").key("key").type("type");//add detected URLs and return the added URLs(CrawlDatums)//and set their type and meta infonext.addAndReturn("detected URL list").type("type").meta("page_num",10);//add detected URL and return next//and modify the type and meta info of all the CrawlDatums in next,//including the added URLnext.add("detected URL").type("type").meta("page_num",10);//add detected URLs and return next//and modify the type and meta info of all the CrawlDatums in next,//including the added URLsnext.add("detected URL list").type("type").meta("page_num",10);
You don't need to consider how to filter duplicated URLs, the crawler will filter them automatically.
Plugins provide a large part of the functionality of WebCollector. There are several kinds of plugins:
- Executor: Plugins which define how to download webpages, how to parse webpages and how to detect new CrawlDatums(urls)
- DBManager: Plugins which maintains the crawling history
- GeneratorFilter: Plugins which generate CrawlDatums(urls) which will be crawled
- NextFilter: Plugins which filter CrawlDatums(urls) which detected by the crawler
Some BreadthCrawler and RamCrawler are the most used crawlers which extends AutoParseCrawler. The following plugins only work in crawlers which extend AutoParseCrawler:
- Requester: Plugins which define how to do http request
- Visitor: Plugins which define how to parse webpages and how to detect new CrawlDatums(urls)
Plugins can be mounted as follows:
crawler.setRequester(xxxxx);crawler.setVisitor(xxxxx);crawler.setNextFilter(xxxxx);crawler.setGeneratorFilter(xxxxx);crawler.setExecutor(xxxxx);crawler.setDBManager(xxxxx);
AutoParseCrawler is also an Executor plugin, a Requester plugin and a Visitor plugin. By default it use itsself as the Executor plugin, Request Plugin and Visitor plugin. So if you want to write a plugin for AutoParseCrawler, you have two ways:
- Just override the corresponding methods of your AutoParseCrawler. For example, if you are using BreadthCrawler, all you have to do is override the
Page getResponse(CrawlDatum crawlDatum)method. - Create a new class which implements Requester interface and implement the
Page getResponse(CrawlDatum crawlDatum)method of the class. Instantiate the class and usecrawler.setRequester(the instance)to mount the plugin to the crawler.
Creating a Requester plugin is very easy. You just need to create a new class which implements Requester interface and implement thePage getResponse(CrawlDatum crawlDatum) method of the class.OkHttpRequester is a Requester Plugin provided by WebCollector. You can find the code here:OkHttpRequester.class.
Most of the time, you don't need to write a Requester plugin from the scratch. Creating a Requester plugin by extending the OkHttpRequester is a convenient way.
Configuration mechanism of WebCollector is redesigned in version 2.70. The above exampleManualNewsCrawler.java also shows how to use configuration to customize your crawler.
Before version 2.70, configuration is maintained by static variables in classcn.edu.hfut.dmic.webcollector.util.Config, hence it's cumbersome to assign different configurations to different crawlers.
Since version 2.70, each crawler can has its own configuration. You can usecrawler.getConf() to get it orcrawler.setConf(xxx) to set it. By default, all crawlers use a singleton default configuration, which could be get by Configuration.getDefault(). So in the above exampleManualNewsCrawler.java,crawler.getConf().set("xxx", "xxx") would affect the default configuration, which may be used by other crawlers.
If you want to change the configuration of a crawler without affecting other crawlers, you should manually create a configuration and specify it to the crawler. For example:
Configurationconf =Configuration.copyDefault();conf.set("test_string_key","test_string_value");crawler.getConf().setReadTimeout(1000 *5);crawler.setConf(conf);crawler.getConf().set("test_int_key",10);crawler.getConf().setConnectTimeout(1000 *5);
Configuration.copyDefault() is suggested, because it creates a copy of the singleton default configuration, which contains some necessary key-value pairs, whilenew Configuration() creates an empty configuration.
If you want to stop a crawler and continue crawling the next time, you should do two things:
- Add
crawler.setResumable(true)to your code. - Don't delete the history directory generated by the crawler, which is specified by the crawlPath parameter.
When you callcrawler.start(depth), the crawler will delete the history if you set resumable to false, which is false by default. So if you forget to put 'crawler.setResumable(true)' in your code before the first time you start your crawler, it doesn't matter, because you have no history directory.
WebCollector could automatically extract content from news web-pages:
Newsnews =ContentExtractor.getNewsByHtml(html,url);Newsnews =ContentExtractor.getNewsByHtml(html);Newsnews =ContentExtractor.getNewsByUrl(url);Stringcontent =ContentExtractor.getContentByHtml(html,url);Stringcontent =ContentExtractor.getContentByHtml(html);Stringcontent =ContentExtractor.getContentByUrl(url);ElementcontentElement =ContentExtractor.getContentElementByHtml(html,url);ElementcontentElement =ContentExtractor.getContentElementByHtml(html);ElementcontentElement =ContentExtractor.getContentElementByUrl(url);
About
WebCollector is an open source web crawler framework based on Java.It provides some simple interfaces for crawling the Web,you can setup a multi-threaded web crawler in less than 5 minutes.
Resources
License
Uh oh!
There was an error while loading.Please reload this page.
Stars
Watchers
Forks
Releases
Packages0
Contributors4
Uh oh!
There was an error while loading.Please reload this page.