webmagic

Readme in Chinese

A scalable crawler framework. It covers the whole lifecycle of crawler: downloading, url management, content extraction and persistent. It can simplify the development of a specific crawler.

Features:

• Simple core with high flexibility.
• Simple API for html extracting.
• Annotation with POJO to customize a crawler, no configuration.
• Multi-thread and Distribution support.
• Easy to be integrated.

Install:

Add dependencies to your pom.xml:

	<dependency>
        <groupId>us.codecraft</groupId>
        <artifactId>webmagic-core</artifactId>
        <version>0.2.1</version>
    </dependency>
	<dependency>
        <groupId>us.codecraft</groupId>
        <artifactId>webmagic-extension</artifactId>
        <version>0.2.1</version>
    </dependency>

Get Started:

First crawler:

Write a class implements PageProcessor：

    public class OschinaBlogPageProcesser implements PageProcessor {

        private Site site = Site.me().setDomain("my.oschina.net")
           .addStartUrl("http://my.oschina.net/flashsword/blog");

        @Override
        public void process(Page page) {
            List<String> links = page.getHtml().links().regex("http://my\\.oschina\\.net/flashsword/blog/\\d+").all();
            page.addTargetRequests(links);
            page.putField("title", page.getHtml().xpath("//div[@class='BlogEntity']/div[@class='BlogTitle']/h1").toString());
            page.putField("content", page.getHtml().$("div.content").toString());
            page.putField("tags",page.getHtml().xpath("//div[@class='BlogTags']/a/text()").all());
        }

        @Override
        public Site getSite() {
            return site;

        }

        public static void main(String[] args) {
            Spider.create(new OschinaBlogPageProcesser())
                 .pipeline(new ConsolePipeline()).run();
        }
    }

• page.addTargetRequests(links)

  Add urls for crawling.

You can also use annotation way:

	@TargetUrl("http://my.oschina.net/flashsword/blog/\\d+")
	public class OschinaBlog {

	    @ExtractBy("//title")
	    private String title;

	    @ExtractBy(value = "div.BlogContent",type = ExtractBy.Type.Css)
	    private String content;

	    @ExtractBy(value = "//div[@class='BlogTags']/a/text()", multi = true)
	    private List<String> tags;

	    public static void main(String[] args) {
	        OOSpider.create(
	        	Site.me().addStartUrl("http://my.oschina.net/flashsword/blog"),
				new ConsolePageModelPipeline(), OschinaBlog.class).run();
	    }
	}

Docs and samples:

The architecture of webmagic (refered to Scrapy)

Javadocs: http://code4craft.github.io/webmagic/docs/en/

There are some samples in webmagic-samples package.

Lisence:

Lisenced under Apache 2.0 lisence

Thanks:

To write webmagic, I refered to the projects below :

• Scrapy

  A crawler framework in Python.

  http://scrapy.org/

• Spiderman

  Another crawler framework in Java.

  https://gitcafe.com/laiweiwei/Spiderman