Add relpath option to FilesWriter

IPython/nbconvert/writers/files.py

@@ -25,6 +25,12 b' class FilesWriter(WriterBase):'
                               help="""Directory to write output to.  Leave blank
                               to output to the current directory""")
 
+    relpath = Unicode(
+        "", config=True, 
+        help="""When copying files that the notebook depends on, copy them in
+        relation to this path, such that the destination filename will be
+        os.path.relpath(filename, relpath).""")
+
 
     # Make sure that the output directory exists.
     def _build_directory_changed(self, name, old, new):
@@ -81,8 +87,14 b' class FilesWriter(WriterBase):'
                     # Copy files that match search pattern
                     for matching_filename in glob.glob(filename):
 
+                        # compute the relative path for the filename
+                        if self.relpath:
+                            dest_filename = os.path.relpath(matching_filename, self.relpath)
+                        else:
+                            dest_filename = matching_filename
+
                         # Make sure folder exists.
-                        dest = os.path.join(self.build_directory, matching_filename)
+                        dest = os.path.join(self.build_directory, dest_filename)
                         path = os.path.dirname(dest)
                         self._makedir(path)
 

IPython/nbconvert/writers/tests/test_files.py

@@ -201,3 +201,38 b' class Testfiles(TestsBase):'
                 with open(dest, 'r') as f:
                     output = f.read()
                     self.assertEqual(output, 'e')
+
+    def test_relpath(self):
+        """Can the FilesWriter handle relative paths for linked files correctly?"""
+
+        # Work in a temporary directory.
+        with self.create_temp_cwd():
+
+            # Create test file
+            os.mkdir('sub')
+            with open(os.path.join('sub', 'c'), 'w') as f:
+                f.write('d')
+
+            # Create the resoruces dictionary
+            res = {}
+
+            # Create files writer, test output
+            writer = FilesWriter()
+            writer.files = [os.path.join('sub', 'c')]
+            writer.build_directory = u'build'
+            writer.relpath = 'sub'
+            writer.write(u'y', res, notebook_name="z")
+
+            # Check the output of the file
+            assert os.path.isdir(writer.build_directory)
+            dest = os.path.join(writer.build_directory, 'z')
+            with open(dest, 'r') as f:
+                output = f.read()
+                self.assertEqual(output, u'y')
+
+            # Check to make sure the linked file was copied
+            dest = os.path.join(writer.build_directory, 'c')
+            assert os.path.isfile(dest)
+            with open(dest, 'r') as f:
+                output = f.read()
+                self.assertEqual(output, 'd')