Merge pull request #45 from anusii/zy/16_rdflib_read_remote_turtle

Zy/16 rdflib read remote turtle

example/example_6.dart

@@ -0,0 +1,21 @@
+import 'package:rdflib/rdflib.dart';
+
+main() async {
+  String webLink = 'https://www.w3.org/TR/turtle/examples/example3.ttl';
+
+  // Create a graph to read Turtle file and store info.
+  Graph g = Graph();
+
+  // Parse the Turtle file from the web.
+  await g.parseTurtleFromWeb(webLink);
+
+  // Serialize the Graph for output.
+  g.serialize(format: 'ttl', abbr: 'short');
+  print('-------Serialized String--------\n${g.serializedString}');
+
+  // Print out full format of triples (will use shorthand in serialization/export).
+  print('--------All triples in the graph-------');
+  for (Triple t in g.triples) {
+    print(t);
+  }
+}

lib/src/graph.dart

@@ -1,6 +1,8 @@
 import 'dart:convert';
 import 'dart:io' show File;
 
+import 'package:http/http.dart' as http;
+
 import './namespace.dart';
 import './term.dart';
 import './triple.dart';
@@ -710,6 +712,34 @@ class Graph {
     }
   }
 
+  /// Parses a valid turtle file from a web link [webLink].
+  ///
+  /// Updates [Graph.ctx], [Graph.groups] and [Graph.triples] in the process.
+  /// The [webLink] should point to a valid Turtle (.ttl) file to ensure correct parsing.
+  /// If the [webLink] does not point to a .ttl file, it might cause unexpected parsing errors.
+  Future<void> parseTurtleFromWeb(String webLink) async {
+    String fileContent = '';
+
+    try {
+      // Fetch the content from the web link.
+      final response = await http.get(
+        Uri.parse(webLink),
+      );
+
+      if (response.statusCode == 200) {
+        fileContent = utf8.decode(response.bodyBytes);
+
+        // Parse the Turtle content.
+        parseTurtle(fileContent);
+      } else {
+        print(
+            'Failed to load content from $webLink. Status code: ${response.statusCode}');
+      }
+    } catch (e) {
+      print('Failed to load content from $webLink. Error: $e');
+    }
+  }
+
   /// Finds the line number of a given triple in the content.
   ///
   /// This is a helper method to aid in error reporting by providing the line number.

pubspec.yaml

@@ -5,14 +5,14 @@ homepage: https://github.com/anusii/rdflib
 repository: https://github.com/anusii/rdflib
 
 environment:
-  sdk: ">=3.0.0 <4.0.0"
+  sdk: '>=3.0.0 <4.0.0'
 
 dependencies:
+  http: ^1.2.1
   logging: ^1.1.0
   petitparser: ^6.0.1
-  http: ^1.1.0
   uuid: ^4.4.1
-  
+
 dev_dependencies:
   lints: ^2.0.1
   test: ^1.22.0