Merge pull request #3 from robguttman/master

Addresses issue #2 - maintains original header/field order.

Author: mjumbewu

.gitignore

@@ -4,3 +4,7 @@ dist/
 build/
 *.egg-info/
 *~
+
+/.settings/
+/.pydevproject
+/.project

rest_framework_csv/orderedrows.py

@@ -0,0 +1,6 @@
+class OrderedRows(list):
+    """
+    Maintains original header/field ordering.
+    """
+    def __init__(self, header):
+        self.header = header

rest_framework_csv/parsers.py

@@ -2,6 +2,7 @@
 
 from rest_framework.parsers import BaseParser
 from rest_framework.exceptions import ParseError
+from rest_framework_csv.orderedrows import OrderedRows
 
 
 class CSVParser(BaseParser):
@@ -19,10 +20,9 @@ def parse(self, stream, media_type=None, parser_context=None):
 
         try:
             rows = csv.reader(stream, delimiter=delimiter)
-            header = rows.next()
-            data = []
+            data = OrderedRows(rows.next())
             for row in rows:
-                row_data = dict(zip(header, row))
+                row_data = dict(zip(data.header, row))
                 data.append(row_data)
             return data
         except Exception, exc:

rest_framework_csv/renderers.py

@@ -2,6 +2,7 @@
 from collections import defaultdict
 from rest_framework.renderers import *
 from StringIO import StringIO
+from rest_framework_csv.orderedrows import OrderedRows
 
 class CSVRenderer(BaseRenderer):
     """
@@ -43,23 +44,24 @@ def tablize(self, data):
             # fall into.
             data = self.flatten_data(data)
 
-            # Get the set of all unique headers, and sort them.
-            headers = set()
-            for item in data:
-                headers.update(item.keys())
-            headers = sorted(headers)
+            # Get the set of all unique headers, and sort them (unless already provided).
+            if not data.header:
+                headers = set()
+                for item in data:
+                    headers.update(item.keys())
+                data.header = sorted(headers)
 
             # Create a row for each dictionary, filling in columns for which the
             # item has no data with None values.
             rows = []
             for item in data:
                 row = []
-                for key in headers:
+                for key in data.header:
                     row.append(item.get(key, None))
                 rows.append(row)
 
             # Return your "table", with the headers as the first row.
-            return [headers] + rows
+            return [data.header] + rows
 
         else:
             return []
@@ -70,7 +72,7 @@ def flatten_data(self, data):
         each exactly one level deep. The key for each value in the dictionaries
         designates the name of the column that the value will fall into.
         """
-        flat_data = []
+        flat_data = OrderedRows(data.header if hasattr(data, 'header') else None)
         for item in data:
             flat_item = self.flatten_item(item)
             flat_data.append(flat_item)

rest_framework_csv/tests.py

@@ -69,6 +69,14 @@ def test_render_a_list_with_unicode_elements(self):
         dump = renderer.render([{u'a': 1, u'b': u'hello\u2014goodbye', u'c': 'http://example.com/'}])
         self.assertEqual(dump, (u'a,b,c\r\n1,hello—goodbye,http://example.com/\r\n').encode('utf-8'))
 
+    def test_render_ordered_rows(self):
+        parser = CSVParser()
+        csv_file = 'v1,v2,v3\r\na,1,2.3\r\nb,4,5.6\r\n'
+        data = parser.parse(StringIO(csv_file))
+        renderer = CSVRenderer()
+        dump = renderer.render(data)
+        self.assertEqual(dump, csv_file) # field order should be maintained
+
 
 class TestCSVParser(TestCase):