class Nanoc::DataSource
Responsible for loading site data. It is the (abstract) superclass for all data sources. Subclasses must at least implement the data reading methods ({#items} and {#layouts}).
Apart from the methods for loading and storing data, there are the {#up} and {#down} methods for bringing up and tearing down the connection to the data source. These should be overridden in subclasses. The {#loading} method wraps {#up} and {#down}. {#loading} is a convenience method for the more low-level methods {#use} and {#unuse}, which respectively increment and decrement the reference count; when the reference count goes from 0 to 1, the data source will be loaded ({#up} will be called) and when the reference count goes from 1 to 0, the data source will be unloaded ({#down} will be called).
@abstract Subclasses should at least implement {#items} and {#layouts}.
Attributes
@return [Hash] The configuration for this data source. For example,
online data sources could contain authentication details.
@return [String] The root path where items returned by this data source
should be mounted.
@return [String] The root path where layouts returned by this data
source should be mounted.
Public Class Methods
# File lib/nanoc/base/repos/data_source.rb, line 32 def initialize(site_config, items_root, layouts_root, config) @site_config = site_config @items_root = items_root @layouts_root = layouts_root @config = config || {} @references = 0 end
Public Instance Methods
Brings down the connection to the data. This method should undo the effects of the {#up} method. For example, a database connection established in {#up} should be closed in this method.
Subclasses may override this method, but are not required to do so; the default implementation simply does nothing.
@return [void]
# File lib/nanoc/base/repos/data_source.rb, line 99 def down end
Returns the collection of items (represented by {Nanoc::Int::Item}) in this site. The default implementation simply returns an empty array.
Subclasses should not prepend `items_root` to the item's identifiers, as this will be done automatically.
Subclasses may override this method, but are not required to do so; the default implementation simply does nothing.
@return [Enumerable] The collection of items
# File lib/nanoc/base/repos/data_source.rb, line 112 def items [] end
Returns the collection of layouts (represented by {Nanoc::Int::Layout}) in this site. The default implementation simply returns an empty array.
Subclasses should prepend `layout_root` to the layout's identifiers, since this is not done automatically.
Subclasses may override this method, but are not required to do so; the default implementation simply does nothing.
@return [Enumerable] The collection of layouts
# File lib/nanoc/base/repos/data_source.rb, line 126 def layouts [] end
Loads the data source when necessary (calling {#up}), yields, and unloads (using {#down}) the data source when it is not being used elsewhere. All data source queries and data manipulations should be wrapped in a {#loading} block; it ensures that the data source is loaded when necessary and makes sure the data source does not get unloaded while it is still being used elsewhere.
@return [void]
# File lib/nanoc/base/repos/data_source.rb, line 49 def loading use yield ensure unuse end
Creates a new in-memory item instance. This is intended for use within the {#items} method.
@param [String] content The uncompiled item content
(if it is a textual item) or the path to the filename containing the content (if it is a binary item).
@param [Hash] attributes A hash containing this item's attributes.
@param [String] identifier This item's identifier.
@param [Boolean] binary Whether or not this item is binary
# File lib/nanoc/base/repos/data_source.rb, line 142 def new_item(content, attributes, identifier, binary: false) content = Nanoc::Int::Content.create(content, binary: binary) Nanoc::Int::Item.new(content, attributes, identifier) end
Creates a new in-memory layout instance. This is intended for use within the {#layouts} method.
@param [String] raw_content The raw content of this layout.
@param [Hash] attributes A hash containing this layout's attributes.
@param [String] identifier This layout's identifier.
# File lib/nanoc/base/repos/data_source.rb, line 155 def new_layout(raw_content, attributes, identifier) Nanoc::Int::Layout.new(raw_content, attributes, identifier) end
Marks the data source as unused by the caller.
Calling this method decreases the internal reference count. When the reference count reaches zero, i.e. when the data source is not used any more, the data source will be unloaded ({#down} will be called).
@return [void]
# File lib/nanoc/base/repos/data_source.rb, line 75 def unuse @references -= 1 down if @references == 0 end
Brings up the connection to the data. Depending on the way data is stored, this may not be necessary. This is the ideal place to connect to the database, for example.
Subclasses may override this method, but are not required to do so; the default implementation simply does nothing.
@return [void]
# File lib/nanoc/base/repos/data_source.rb, line 88 def up end
Marks the data source as used by the caller.
Calling this method increases the internal reference count. When the data source is used for the first time (first {#use} call), the data source will be loaded ({#up} will be called).
@return [void]
# File lib/nanoc/base/repos/data_source.rb, line 63 def use up if @references == 0 @references += 1 end