comparison pyspark/n3Parser.py @ 0:e34cf1b6fe09 tip

commit

+# Part of DML (Digital Music Laboratory)
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+
+from rdflib import Graph
+from rdflib.plugins.parsers.notation3 import BadSyntax
+import warnings
+import codecs
+import platform
+
+# Load and parse an n3 file
+def get_rdf_graph_from_n3(n3_file_uri):
+
+    graph = Graph()
+
+    try:
+        graph.parse(n3_file_uri, format="n3")
+    except UnicodeDecodeError:
+        
+        n3_file_str = uri2path(n3_file_uri)
+        n3_file_iso = codecs.open(n3_file_str, 'r', "iso-8859-1")
+
+        # check if n3 is valid and parse
+        # repair if necessary
+        graph = parse_potentially_corrupt_n3(n3_file_iso.read())
+
+    except (AssertionError, BadSyntax):
+
+        n3_file_str = uri2path(n3_file_uri)
+        n3_file = open(n3_file_str, 'r')
+        graph = parse_potentially_corrupt_n3(n3_file.read())
+
+    return graph
+
+# can parse truncated n3
+def parse_potentially_corrupt_n3(content):
+    feature_graph = Graph()
+    # test if file is complete. 
+    # if not, delete the last corrupted entry
+    if not '.' in content[-4:]:
+        warnings.warn("Incomplete rdf file, ignoring last entry")
+        # we find the last correct event
+        lastentry = content.rfind(':event')
+        feature_graph.parse(data=content[:lastentry], format="n3")
+    else:
+        feature_graph.parse(data=content, format="n3")
+
+    return feature_graph
+
+# returns filepath from url
+def uri2path(n3_file_uri):
+    
+    n3_file_uri_str = n3_file_uri.__str__()
+    
+    # Assume that n3_file_uri_str starts with 'file://' - we need to remove that
+    if 'Win' in platform.system():
+        FILE_URI_START_INDEX = 8
+    else:
+        FILE_URI_START_INDEX = 7
+            
+    n3_file_str = n3_file_uri_str[FILE_URI_START_INDEX:len(n3_file_uri_str)]
+    return n3_file_str