initial support for prefixes

Author: Niels V

README.md

@@ -406,6 +406,7 @@ In the example below the documents index contains a property `topics` that maps
 }
 ```
 
+
 ##### File content property
 To make the content of a file searchable, it needs to be indexed as a property in a search index. Basic indexing of PDF, Word etc. files is provided using a local [Apache Tika](https://tika.apache.org/) instance. A default ingest pipeline named `attachment` is created on startup of the mu-search service. Note that this is under development and liable to change.
 
@@ -643,6 +644,30 @@ The example below contains 2 simple indexes for documents and creative works, an
     ]
 }
 ```
+#### Using Prefixes
+To make the configuration more concise and maintainable, you can define prefixes for commonly used URI namespaces. Prefixes are defined at the root level of the configuration using the `prefixes` property:
+
+```json
+{
+  "prefixes": {
+    "foaf": "http://xmlns.com/foaf/0.1/",
+    "dct": "http://purl.org/dc/terms/",
+    "skos": "http://www.w3.org/2004/02/skos/core#"
+  },
+  "types": [
+    {
+      "type": "document",
+      "on_path": "documents",
+      "rdf_type": "foaf:Document",
+      "properties": {
+        "title": "dct:title",
+        "label": "skos:prefLabel",
+        "creator": "^foaf:made"
+      }
+    }
+  ]
+}
+```
 
 #### Elasticsearch settings
 Elasticsearch provides a lot of [index configuration settings](https://www.elastic.co/guide/en/elasticsearch/reference/current/index-modules.html) for analysis, logging, etc. Mu-search allows to provide this configuration for the whole domain and/or to be overridden (currently not merged!) on a per-type basis.

lib/mu_search/config_parser.rb

@@ -16,7 +16,8 @@ def self.parse(path)
         eager_indexing_groups: [],
         update_wait_interval_minutes: 1,
         number_of_threads: 1,
-        enable_raw_dsl_endpoint: false
+        enable_raw_dsl_endpoint: false,
+        prefixes: {}
       }
 
       json_config = JSON.parse(File.read(path))
@@ -48,7 +49,9 @@ def self.parse(path)
         config[:eager_indexing_groups] = json_config["eager_indexing_groups"]
       end
       config[:ignored_allowed_groups] = json_config["ignored_allowed_groups"] || []
-      config[:type_definitions] = Hash[MuSearch::IndexDefinition.from_json_config(json_config["types"])]
+      config[:prefixes] = json_config["prefixes"] || {}
+      config[:type_definitions] = Hash[MuSearch::IndexDefinition.from_json_config(json_config["types"], config[:prefixes])]
+
       config
     end
 
@@ -120,6 +123,9 @@ def self.validate_config(json_config)
       if json_config.has_key?("ignored_allowed_groups")
         errors = errors.concat(self.validate_ignored_allowed_groups(json_config["ignored_allowed_groups"]))
       end
+      if json_config.has_key?("prefixes")
+        errors = errors.concat(self.validate_prefixes(json_config["prefixes"]))
+      end
       if errors.length > 0
         Mu::log.error("CONFIG_PARSER") { errors.join("\n") }
         raise "invalid config"
@@ -242,5 +248,28 @@ def self.validate_eager_indexing_groups(groups)
 
       errors
     end
+
+    def self.validate_prefixes(prefixes)
+      errors = []
+      if ! prefixes.kind_of?(Hash)
+        errors << "prefixes should be an object mapping prefix names to URIs"
+      else
+        prefixes.each do |prefix, uri|
+          if ! prefix.kind_of?(String)
+            errors << "prefix name should be a string: #{prefix.inspect}"
+          end
+          if ! uri.kind_of?(String)
+            errors << "prefix URI should be a string: #{uri.inspect}"
+          else
+            begin
+              parsed_uri = URI.parse(uri)
+            rescue URI::InvalidURIError => e
+              errors << "prefix URI '#{uri}' is not a valid URI: #{e.message}"
+            end
+          end
+        end
+      end
+      errors
+    end
   end
 end

lib/mu_search/index_definition.rb

@@ -1,3 +1,5 @@
+require_relative './prefix_utils'
+
 module MuSearch
   # This class represents index definitions as defined in the configuration file of mu-search
   # in the config file you will find these definitions on the the keyword "types"
@@ -58,23 +60,34 @@ def self.create_composite_sub_definitions(composite_definition, definitions)
 
     # builds a tuples mapping the index name to the full definition for all provided types
     # expects all types as param
-    def self.from_json_config(all_definitions)
+    def self.from_json_config(all_definitions, prefixes = {})
       all_definitions.collect do |definition|
         name = definition["type"]
         composite_types = []
         if definition["composite_types"]
           composite_types = create_composite_sub_definitions(definition, all_definitions)
           composite_types.each do |definition|
-            ensure_uuid_in_properties definition.properties
+            build_property_definitions(definition.properties, prefixes)
           end
         else
           # ensure uuid is included because it may be used for folding
-          ensure_uuid_in_properties definition["properties"]
+          build_property_definitions(definition["properties"], prefixes)
+        end
+
+        # Expand prefixes in rdf_type if present
+        rdf_type = definition["rdf_type"]
+        if rdf_type
+          if rdf_type.is_a?(Array)
+            rdf_type = rdf_type.map { |t| PrefixUtils.expand_prefix(t, prefixes) }
+          else
+            rdf_type = PrefixUtils.expand_prefix(rdf_type, prefixes)
+          end
         end
+
         index_definition = IndexDefinition.new(
           name: name,
           on_path: definition["on_path"],
-          rdf_type: definition["rdf_type"],
+          rdf_type: rdf_type,
           composite_types: composite_types,
           properties: definition["properties"],
           mappings: definition["mappings"],
@@ -84,16 +97,20 @@ def self.from_json_config(all_definitions)
       end
     end
 
-    def self.ensure_uuid_in_properties properties
-      properties["uuid"] = ["http://mu.semte.ch/vocabularies/core/uuid"] unless properties.key?("uuid")
+    def self.build_property_definitions(properties, prefixes)
+      ensure_uuid_property(properties)
       properties.each do |(key, value)|
-        property_definition = PropertyDefinition.from_json_config(key, value)
+        property_definition = PropertyDefinition.from_json_config(key, value, prefixes)
         if property_definition.type == "nested"
-          ensure_uuid_in_properties value["properties"]
+          build_property_definitions(value["properties"], prefixes)
         end
       end
     end
 
+    def self.ensure_uuid_property(properties)
+      properties["uuid"] = ["http://mu.semte.ch/vocabularies/core/uuid"] unless properties.key?("uuid")
+    end
+
     def type
       @name
     end

lib/mu_search/prefix_utils.rb

@@ -0,0 +1,14 @@
+module MuSearch
+  module PrefixUtils
+    def self.expand_prefix(uri, prefixes)
+      return uri unless uri.is_a?(String)
+
+      prefixes.each do |prefix, base_uri|
+        if uri.start_with?("#{prefix}:")
+          return uri.sub("#{prefix}:", base_uri)
+        end
+      end
+      uri
+    end
+  end
+end

lib/mu_search/property_definition.rb

@@ -1,3 +1,5 @@
+require_relative './prefix_utils'
+
 module MuSearch
   class PropertyDefinition
     PROPERTY_TYPES = ["simple", "nested", "attachment", "language-string"]
@@ -16,7 +18,7 @@ def initialize(name: , path:,  type: "auto", rdf_type: nil, sub_properties:)
       end
     end
 
-    def self.from_json_config(name, config)
+    def self.from_json_config(name, config, prefixes = {})
       type = "simple"
       rdf_type = sub_properties = pipeline = nil
       if config.is_a?(Hash)
@@ -26,7 +28,7 @@ def self.from_json_config(name, config)
         elsif config.key?("properties")
           type = "nested"
           sub_properties = config["properties"].map do |subname, subconfig|
-            from_json_config(subname, subconfig)
+            from_json_config(subname, subconfig, prefixes)
           end
           rdf_type = config["rdf_type"]
         elsif config.key?("type") && config["type"] == "language-string"
@@ -38,6 +40,10 @@ def self.from_json_config(name, config)
         path = [config]
       end
 
+      path = path.map do |p|
+        PrefixUtils.expand_prefix(p, prefixes)
+      end
+
       PropertyDefinition.new(
         name: name,
         type: type,
@@ -46,6 +52,5 @@ def self.from_json_config(name, config)
         sub_properties: sub_properties,
       )
     end
-
   end
 end