Webscrapper to JSON or EMF model

Installation

Standard mode

Install and open Eclipse-Installer, then just go on settings and enable Web-Links.

Afterwards, click twice on

Advanced mode

Install Eclipse-Installer.

Advanced mode > Add user products > and choose Setup file

In an existing Eclipse platform

Help > Install new Software > and choose Update site

How to use it

Create a new project

Once created, it will appear in the Project Explorer. Just double click on the .retriever file to open the editor.

Describe how to fetch the site

Use URL Retriever, Element Retriever and Attribute Retriever to describe how to fetch the site

In this sample, we will retrieve from a Wikipedia page, its title, the lastModified date and artists of the music supergroup described in the page.

Run it

• Select the top highwaymen element

• On the main toolbar, just click on Fetch

Result appears on the bottom.

By doubleclicking on the top highwaymen, the JSON editor opens.

Fetch sub pages

From an element, we can fetch sub pages.

Here, retrieved links are relative, by using Set Variable, we can compute a fullURL.

Then we add a child URL element towards this fullURL and retrieve some attributes from the sub page.

By Fetch again, the result becomes:

or as JSON:

Models manipulation

LoadResource allows to create/load a resource from workspace.

CreateEObject allows to create the given EObject.

CreateEAttribute allows to set the given attribute on an EObject.

CreateEReference allows to set the given reference on an EObject.

For instance, load the resource schema.ecore, retrieve the root element. If the resource is empty, create a root element called Artists

Some expressions used above

• resource:<variable>.root expression allows to retrieve the root of a resource.

• variable:<variable>.isNull returns whether the variable is null or not.

With the following example, we will create an EClass into schema.ecore for each album on the page.

If we fetch again, new albums released since then will be added to the file.

Reuse retrievers

ReferencedRetriever allows to reuse a retriever. According to variables, it may behave differently.

For instance, if we update our top artistPage from

to

We can now fetch two different pages. The ecore will contain both artist albums.

Additional operators

If allowing to process only if the conditionExpression is true

TransformationService allowing to define a service from a java class and method, to text-processing fetched results using java.

TransformationRetriever allowing to retrieve an element, but passed directly to a TransformationService [TO IMPROVE / TO DELETE / TBD]