merged in parser related changes from 3.0 branch; fixing pep8 module name issues for URLInputSource and company along the way

1 files changed, 162 insertions, 0 deletions

diff --git a/rdflib/parser.py b/rdflib/parser.py
new file mode 100644
index 00000000..b84e5f44
--- /dev/null
+++ b/rdflib/parser.py
@@ -0,0 +1,162 @@
+"""
+This module defines the parser plugin interface and contains other
+related parser support code.
+
+The module is mainly useful for those wanting to write a parser that
+can plugin to rdflib. If you are wanting to invoke a parser you likely
+want to do so through the Graph class parse method.
+
+"""
+
+import os
+import __builtin__
+import warnings
+from urllib import pathname2url, url2pathname
+from urllib2 import urlopen, Request
+from urlparse import urljoin
+from StringIO import StringIO
+from xml.sax import xmlreader
+from xml.sax.saxutils import prepare_input_source
+import types
+try:
+    _StringTypes = (types.StringType, types.UnicodeType)
+except AttributeError:
+    _StringTypes = (types.StringType,)
+
+from rdflib import __version__
+from rdflib.term import URIRef, Namespace
+
+
+class Parser(object):
+
+    def __init__(self):
+        pass
+
+    def parse(self, source, sink):
+        pass
+
+
+class InputSource(xmlreader.InputSource):
+    """
+    TODO:
+    """
+
+    def __init__(self, system_id = None):
+        xmlreader.InputSource.__init__(self, system_id=system_id)
+        self.content_type = None
+        
+
+class StringInputSource(InputSource, object):
+    """
+    TODO:
+    """
+
+    def __init__(self, value, system_id=None):
+        super(StringInputSource, self).__init__(system_id)
+        stream = StringIO(value)
+        self.setByteStream(stream)
+        # TODO:
+        #   encoding = value.encoding
+        #   self.setEncoding(encoding)
+
+
+headers = {
+    'Accept': 'application/rdf+xml,text/rdf+n3;q=0.9,application/xhtml+xml;q=0.5',
+    'User-agent': 'rdflib-%s (http://rdflib.net/; eikeon@eikeon.com)' % __version__
+    }
+
+
+class URLInputSource(InputSource, object):
+    """
+    TODO:
+    """
+
+    def __init__(self, system_id=None):
+        super(URLInputSource, self).__init__(system_id)
+        self.url = system_id
+        # So that we send the headers we want to...
+        req = Request(system_id, None, headers)
+        
+        file = urlopen(req)
+        self.content_type = file.info().get('content-type')
+        self.content_type = self.content_type.split(";", 1)[0]
+        self.setByteStream(file)
+        # TODO: self.setEncoding(encoding)
+
+    def __repr__(self):
+        return self.url
+
+
+class FileInputSource(InputSource, object):
+    """
+    TODO:
+    """
+
+    def __init__(self, file):
+        base = urljoin("file:", pathname2url(os.getcwd()))
+        system_id = URIRef(file.name, base=base)
+        super(FileInputSource, self).__init__(system_id)
+        self.file = file
+        self.setByteStream(file)
+        # TODO: self.setEncoding(encoding)
+
+    def __repr__(self):
+        return `self.file`
+
+
+def create_input_source(source=None, publicID=None, 
+                        location=None, file=None, data=None):
+    """
+    Return an appropriate InputSource instance for the given
+    parameters.
+    """
+
+    # TODO: test that exactly one of source, location, file, and data
+    # is not None.
+
+    input_source = None
+
+    if source is not None:
+        if isinstance(source, InputSource):
+            input_source = source
+        else:
+            if isinstance(source, _StringTypes):
+                location = source
+            elif hasattr(source, "read") and not isinstance(source, Namespace):
+                f = source
+                input_source = InputSource()
+                input_source.setByteStream(f)
+                if hasattr(f, "name"):
+                    input_source.setSystemId(f.name)
+            else:
+                raise Exception("Unexpected type '%s' for source '%s'" % (type(source), source))
+
+    if location is not None:
+        base = urljoin("file:", "%s/" % pathname2url(os.getcwd()))
+        absolute_location = URIRef(location, base=base).defrag()
+        if absolute_location.startswith("file:///"):
+            filename = url2pathname(absolute_location.replace("file:///", "/"))
+            file = __builtin__.file(filename, "rb")
+        else:
+            input_source = URLInputSource(absolute_location)
+        publicID = publicID or absolute_location
+
+    if file is not None:
+        input_source = FileInputSource(file)
+
+    if data is not None:
+        input_source = StringInputSource(data)
+
+    if input_source is None:
+        raise Exception("could not create InputSource")
+    else:
+        if publicID:
+            input_source.setPublicId(publicID)
+
+        # TODO: what motivated this bit?
+        id = input_source.getPublicId()
+        if id is None:
+            input_source.setPublicId("")
+        return input_source
+        
+