dtoo

Overview ¶

Dtoo exposes an HTML scraper API inspired by the artoo.js Scrape API https://medialab.github.io/artoo/scrape/.

The dtoo scrape API closely follows artoo's scrape API, but is slightly modified to suit Go. The biggest changes are that "scrapeTable" is not implemented and "scrapeOne" is implemented via the ScrapeFromXxxWithLimit functions.

The artoo example

artoo.scrape('li', {id: 'id', content: 'text'});

written for dtoo would look like this.

dtoo.ScrapeFromUrl("li", dtoo.Model{"id": "id", "content": "text"}, url)

The above example will return a slice of dtoo.Model objects each with the following keys: {id, content}.

The dtoo data model passed to the ScrapeXxx and ScrapeXxxWithLimit functions can be a string, func (s *goquery.Selection) (interface{}, error), dtoo.Model or dtoo.RetrieverModel.

Retrieves a slice of post id attributes using a string data model.

dtoo.ScrapeFromUrl(".post", "id", url)

Retrieves a slice of post comments using a function data model. When using a function you are exposed to the low level goquery API for scraping out content from the DOM.

type Comment struct {
  Author sring
  Content string
}

dtoo.ScrapeFromUrl(".post", func (s *goquery.Selection) (interface{}, error) {
  var err error = nil
  comments := make([]Comment, 0)

  s.Find(".comments").EachWithBreak(func (i int, s *goquery.Selection) bool {
    comment := Comment{
      Author: s.Find('.comment-author').Text(),
    }

    if content,e := s.Find('.comment-content').Html(); e == nil {
      comment.Content = content
    } else {
      // Save error and exit
      err = e
      return false
    }

    comments = append(comments, comment)
    return true
  })

  return comments, err
}, url)

Retrieves a slice of dtoo.Model objects each with the following keys {Id, Title, PublishDate}.

dtoo.ScrapeFromUrl(".post", dtoo.Model{
  "Id": "id",
  "Title": "title",
  "PublishDate": "datetime"
}, url)

Using dtoo.Model you can nest dtoo.RetrieverModel objects and functions as keys in your model to retrieve infinitely complex models. This example retrieves a slice of dtoo.Model objects with the following properties {Id, Title, PublishedDate, Comments: [{Id, Author, Content}]}.

dtoo.ScrapeFromUrl(".post", dtoo.Model{
  "Id": "id",
  "Title": dtoo.RetrieverModel{Sel: ".post-title", Method: "text"},
  "PublishDate": dtoo.RetrieverModel{Sel: ".publisehed-date", Attr: "datetime"},
  "Comments": func (s *goquery.Selection) (interface{}, error) {
    // We make a recursive call to dtoo.Scrape to make things easy.
    return dtoo.Scrape(".comment", dtoo.Model{
      "Id": "id",
      "Author": dtoo.RetrieverModel{Sel: ".comment-author", Method: "text"},
      "Content": dtoo.RetrieverModel{Sel: ".comment-content", Method: "html"},
    }, s)
  },
}, url)

The above example could be alternatively achieved by using the recursive Scrape setting of RetrieverModel.

dtoo.ScrapeFromUrl(".post", dtoo.Model{
  "Id": "id",
  "Title": dtoo.RetrieverModel{Sel: ".post-title", Method: "text"},
  "PublishDate": dtoo.RetrieverModel{Sel: ".publisehed-date", Attr: "datetime"},
  "Comments": dtoo.RetrieverModel{
    Scrape: dtoo.ScrapeObject{
      Iterator: ".comment",
      Data: dtoo.Model{
        "Id": "id",
        "Author": dtoo.RetrieverObject{Sel: ".comment-author", Method: "text"},
        "Content": dtoo.RetrieverObject{Sel: ".comment-content", Method: "html"},
      },
    },
  },
}, url)