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| libraryDependencies ++= Seq( | |
| "org.jsoup" % "jsoup" % "1.6.1" | |
| ) |
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| import org.jsoup.Jsoup | |
| import org.jsoup.nodes.Document | |
| import org.jsoup.nodes.Element | |
| import org.jsoup.select.Elements | |
| import scala.collection.JavaConversions._ | |
| import java.net.{ URL, MalformedURLException } | |
| import scala.util.control.Exception._ | |
| sealed case class Link(title: String, href: String) | |
| case class WebDocument(title: String, | |
| body: String, | |
| links: Seq[Link], | |
| metaDescription: String) | |
| object Crawler { | |
| type JDoc = org.jsoup.nodes.Document | |
| def get(url: String): JDoc = Jsoup.connect(url).get() | |
| def titleText(doc: JDoc): String = doc.select("title").text | |
| def bodyText(doc: JDoc): String = doc.select("body").text | |
| /** | |
| * Allows for extraction without null pointer exceptions | |
| * | |
| */ | |
| def safeMetaExtract(doc: JDoc, meta: String): String = { | |
| val result = doc.select("meta[name=" ++ meta ++ "]").first | |
| Option(result) match { | |
| case Some(v) => v.attr("content") | |
| case None => "" | |
| } | |
| } | |
| def metaKeywords(doc: JDoc): String = safeMetaExtract(doc, "keywords") | |
| def metaDescription(doc: JDoc): String = safeMetaExtract(doc, "description") | |
| /** | |
| * Extracts links from a document | |
| * | |
| */ | |
| def linkSequence(doc: JDoc): Seq[Link] = { | |
| val links = doc.select("a[href]").iterator.toList | |
| links.map { l => Link(l.text, l.attr("href")) } | |
| } | |
| def extract(doc: JDoc): WebDocument = { | |
| val title: String = titleText(doc) | |
| val body: String = bodyText(doc) | |
| val links: Seq[Link] = linkSequence(doc) | |
| val desc: String = metaDescription(doc) | |
| WebDocument(title, body, links, desc) | |
| } | |
| def safeURL(url: String): Option[String] = { | |
| val result = catching(classOf[MalformedURLException]) opt new URL(url) | |
| result match { | |
| case Some(v) => Some(v.toString) | |
| case None => None | |
| } | |
| } | |
| /** | |
| * Crawl a URL and return a WebDocument | |
| * | |
| */ | |
| def crawl(url: String): WebDocument = { | |
| val f = extract _ compose get | |
| f(url) | |
| } | |
| } |
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