Class TaliaCore::DataTypes::MimeMapping
In: lib/talia_core/data_types/mime_mapping.rb
Parent: Object

Mapping from Mime types to data classes and importing methods for DataRecord.

See the DataTypes::DataLoader module to see how the import works. In a nutshell, each MIME type can be connected either to a DataTypes::FileRecord type that will be used for new data records, or the MIME type can be connected to a handler method that will do the creation.

Default Mappings

See the source code of the mapping_hash method for the detailed default mapping. It goes something like this:

Configure the MIME mappings for Talia

The mapping can be configured in Rails’ initializer files (e.g. config/initializers/talia.rb): 

  TaliaCore::DataTypes::MimeMapping.add_mapping(:tiff, :image_data, :create_iip)

Add a mapping for each MIME type that you need, or where you want to change the default mapping

Methods

add_mapping   class_type_from   loader_type_from   mapping_hash  

Public Class methods

add_mapping(mime_type, data_class, handler = nil)

Set a new mapping for the given MIME type. If only a class is given, this will use the class to create new data records from. If a symbol is given for data_class, this will take the corresponding class from TaliaCore::DataTypes.

Examples

 # Uses DataTypes::ImageData#create_iip to create new records
 TaliaCore::DataTypes::MimeMapping.add_mapping(:tiff, :image_data, :create_iip)

 # Use the DataTypes::ImageData class for new data records, and create records
 # in the default way (using create_with_file or similar)
 TaliaCore::DataTypes::MimeMapping.add_mapping(:png, DataTypes::ImageData)

[Source]

    # File lib/talia_core/data_types/mime_mapping.rb, line 64
64:         def add_mapping(mime_type, data_class, handler = nil)
65:           mapping = {}
66:           if(!data_class.is_a?(Class))
67:             data_class = TaliaCore::DataTypes.const_get(data_class.to_s.camelize)
68:           end
69:           
70:           raise("Error: #{data_class} is not a valid data class.") unless(data_class.is_a?(Class) && (data_class <= DataRecord))
71:           
72:           mapping[:type] = data_class
73:           mapping[:loader] = handler.to_sym if(handler)
74:           mapping_hash[symbol_for(mime_type)] = mapping
75:           true
76:         end
class_type_from(mime_type)

Gets the data class for the given mime type. For loaders configured through add_mapping, this will always return the class corresponding to data_class. (Otherwise it will return the data_class configured in the default mapping)

[Source]

    # File lib/talia_core/data_types/mime_mapping.rb, line 39
39:         def class_type_from(mime_type)
40:           mapping_for(mime_type)[:type]
41:         end
loader_type_from(mime_type)

Return the "loader type" for the given MIME type. This will return the handler (as a symbol, see add_mapping) if set. If no handler is set, it will return the data_class (as class_type_from).

[Source]

    # File lib/talia_core/data_types/mime_mapping.rb, line 46
46:         def loader_type_from(mime_type)
47:           map = mapping_for(mime_type)
48:           map[:loader] || map[:type]
49:         end
mapping_hash()

Returns the current mapping. This will be automatically initialized with the default mappings.

[Source]

     # File lib/talia_core/data_types/mime_mapping.rb, line 80
 80:         def mapping_hash
 81:           @mapping ||= {
 82:             :xml => { :type => DataTypes::XmlData },
 83:             :html =>{ :type => DataTypes::XmlData },
 84:             :tei => { :type => DataTypes::XmlData },
 85:             :tei_p5 => { :type => DataTypes::XmlData },
 86:             :tei_p4 => { :type => DataTypes::XmlData }, 
 87:             :gml => { :type => DataTypes::XmlData },
 88:             :wittei => { :type => DataTypes::XmlData },
 89:             :hnml => { :type => DataTypes::XmlData },
 90:             :jpeg => { :type => DataTypes::ImageData },
 91:             :tiff => { :type => DataTypes::ImageData },
 92:             :png => { :type => DataTypes::ImageData },
 93:             :gif => { :type => DataTypes::ImageData },
 94:             :bmp => { :type => DataTypes::ImageData },
 95:             :pdf => { :type => DataTypes::PdfData },
 96:             :text => { :type => DataTypes::SimpleText },            
 97:             # Default fallback handler
 98:             :default => { :type => FileRecord }
 99:           }
100:         end

[Validate]