Class: DirectedEdge::Exporter

Inherits:
Object
  • Object
show all
Defined in:
lib/directed_edge.rb

Overview

A very simple class for creating Directed Edge XML files or doing batch updates to a database. This can be done for example with:

exporter = DirectedEdge::Exporter.new('mydatabase.xml')
item = DirectedEdge::Item.new(exporter.database, 'product_1')
item.add_tag('product')
exporter.export(item)
exporter.finish

mydatabase.xml now contains:

<?xml version="1.0" encoding="UTF-8"?>
<directededge version="0.1">
<item id='product_1'><tag>product</tag></item>
</directededge>

Which can then be imported to a database on the server with:

database = DirectedEdge::Database.new('mydatabase', 'mypassword')
database.import('mydatabase.xml')

Alternatively, had the first line been:

exporter = DirectedEdge::Exporter.new(some_database_object)

Then newly created / modfied objects that on which export was called would be queued for a batch update to the database later.

Items may also be exported from existing databases.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(destination) ⇒ Exporter

Begins exporting a collection of items to the given destination. If the destination is a file existing contents will be overwritten. If the destination is an existing database object, updates will be queued until finish is called, at which point they will be uploaded to the webservices in batch.



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# File 'lib/directed_edge.rb', line 267

def initialize(destination)
  if destination.is_a?(String)
    @database = Database.new('exporter')
    @file = File.new(destination, 'w')
  elsif destination.is_a?(Database)
    @database = destination
    @data = []
  else
    raise TypeError.new("Exporter must be passed a file name or database object.")
  end

  write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n\n")
  write("<directededge version=\"0.1\">\n")
end

Instance Attribute Details

#database ⇒ Object (readonly)

Provides a dummy database for use when creating new items to be exported.



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# File 'lib/directed_edge.rb', line 257

def database
  @database
end

Instance Method Details

#export(item) ⇒ Object

Exports the given item to the file passed to the constructor.



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# File 'lib/directed_edge.rb', line 284

def export(item)
  write("#{item.to_xml}\n")
end

#finish ⇒ Object

Writes a closing XML element to the document and closes the file.



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# File 'lib/directed_edge.rb', line 290

def finish
  write("</directededge>\n")
  @file ? @file.close : @database.resource['add'].put(@data.join)
end