Scala library for scraping metadata from specified URLs (e.g. OpenGraph)
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README.md

Metascraper Build Status Coverage Status Maven Central

A non-blocking Scala library that allows you to retrieve meta data from various URLs.

Out of the box, supports HTML content (works with OpenGraph as well as normal HTML meta/image tags), but can be easily extended to support any kind of content (just implement Schema and SchemaFactory) so that you can work with any URL that returns an Array of Bytes.

Tested against Scala 2.10.x, 2.11.x, and 2.12.x.

Installation

Add the following to your build.sbt

libraryDependencies += "com.beachape.metascraper" %% "metascraper" % version

If the above does not work because it cannot be resolved, its likely because it hasn't been synced to Maven central yet. In that case, download a SNAPSHOT release of the same version by adding this to build.sbt

resolvers += "Sonatype OSS Snapshots" at "https://oss.sonatype.org/content/repositories/snapshots"

libraryDependencies += "com.beachape.metascraper" %% "metascraper" % s"$version-SNAPSHOT"

Example usage

Scraper

// You can customise Http here (it is simply Dispatcher's Http client)
val scraper = new Scraper(Http, Seq("http", "https"))

val fData: Future[ScrapedData] = scraper.fetch(ScrapeUrl("https://google.com"))

Custom scraping schema

You can customise scraping by implementing SchemaFactory and Schema.

  • A SchemaFactory needs to implement a method that takes a Response from AsyncHttpClient and returns a list of Schema
  • A Schema is what is used to extract data from the response

This allows you to freely customise the way this lib extracts data from HTTP endpoints, for example as listed on Schema.org.

That said, if all you want to do is implement a custom HTML data scraper, you just need to implement HtmlSchema and pass it along to a ScrapeUrl message inside HtmlSchemas, as follows:

case class CustomHtmlSchema(doc: Document) extends HtmlSchema {
 // Implementations
}

val scraper = new Scraper(httpClient = Http, urlSchemas = Seq("http", "https"))
val scrapeMessage = ScrapeUrl("https://google.com", schemaFactories = Seq(HtmlSchemas(OpenGraph, CustomHtmlSchema, NormalPage)) )
val fData = scraper.fetch(scrapeMessage)

In the above case, HtmlSchemas is a SchemaFactory that creates a Jsoup Document and gives it to the Schemas that it generates. That way, only one String to Document parse needs to happen.

Example applications

  1. Metascraper-service: a RESTful Play2 service that uses this library to scrape data from a requested URL, taking advantage of the tight integration that Play2 has with Akka.

  2. Metascraper-scalatra: same as 1. but built on Scalatra, which is more light-weight and Servlet 3.0 compliant.

Licence

The MIT License (MIT)

Copyright (c) 2015 by Lloyd Chan

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.