Add support for passing kwargs to csv writer

fixes #54 on github
fixes #56 on github

Bump version number for release
Add unit tests
Update documentation

Author: Steve Lamb

README.rst

@@ -31,7 +31,7 @@ Run::
 
    pip install django-queryset-csv
    
-Supports Python 2.6 and 2.7, Django 1.5 and 1.6.
+Supports Python 2.6 and 2.7, Django 1.5, 1.6, and 1.7.
 
 usage
 -----
@@ -69,3 +69,24 @@ views.py::
   def csv_view(request):
       people = Person.objects.values('name', 'favorite_food__name')
       return render_to_csv_response(people)
+
+keyword arguments
+-----------------
+
+This module exports two functions that write CSVs, ``render_to_csv_response`` and ``write_csv``. Both of these functions require their own positional arguments. In addition, they both take three optional keyword arguments:
+
+* ``field_header_map`` - (default: ``None``) A dictionary mapping names of model fields to column header names. If specified, the csv writer will use these column headers. Otherwise, it will use defer to other parameters for rendering column names.
+* ``use_verbose_names`` - (default: ``True``) A boolean determining whether to use the django field's ``verbose_name``, or to use it's regular field name as a column header. Note that if a given field is found in the ``field_header_map``, this value will take precendence.
+* ``field_order`` - (default: ``None``) A list of fields to determine the sort order. This list need not be complete: any fields not specified will follow those in the list with the order they would have otherwise used.
+
+The remaining keyword arguments are *passed through* to the csv writer. For example, you can export a CSV with a different delimiter::
+
+views.py::
+
+  from djqscsv import render_to_csv_response
+
+  def csv_view(request):
+      people = Person.objects.values('name', 'favorite_food__name')
+      return render_to_csv_response(people, delimiter='|')
+
+For more details on possible arguments, see the documentation on `DictWriter <https://docs.python.org/2/library/csv.html#csv.DictWriter>`_.

djqscsv/djqscsv.py

@@ -17,6 +17,12 @@
 
 """ A simple python package for turning django models into csvs """
 
+# Keyword arguments that will be used by this module
+# the rest will be passed along to the csv writer
+DJQSCSV_KWARGS = {'field_header_map': None,
+                  'use_verbose_names': True,
+                  'field_order': None}
+
 
 class CSVException(Exception):
     pass
@@ -45,13 +51,23 @@ def render_to_csv_response(queryset, filename=None, append_datestamp=False,
     return response
 
 
-def write_csv(queryset, file_obj, field_header_map=None,
-              use_verbose_names=True, field_order=None):
+def write_csv(queryset, file_obj, **kwargs):
     """
     The main worker function. Writes CSV data to a file object based on the
     contents of the queryset.
     """
 
+    # process keyword arguments to pull out the ones used by this function
+    field_header_map = kwargs.get('field_header_map', {})
+    use_verbose_names = kwargs.get('use_verbose_names', True)
+    field_order = kwargs.get('field_order', None)
+
+    csv_kwargs = {}
+
+    for key, val in six.iteritems(kwargs):
+        if key not in DJQSCSV_KWARGS:
+            csv_kwargs[key] = val
+
     # add BOM to suppor CSVs in MS Excel
     file_obj.write(u'\ufeff'.encode('utf8'))
 
@@ -82,7 +98,7 @@ def write_csv(queryset, file_obj, field_header_map=None,
                        [field for field in field_names
                         if field not in field_order])
 
-    writer = csv.DictWriter(file_obj, field_names)
+    writer = csv.DictWriter(file_obj, field_names, **csv_kwargs)
 
     # verbose_name defaults to the raw field name, so in either case
     # this will produce a complete mapping of field names to column names
@@ -94,9 +110,8 @@ def write_csv(queryset, file_obj, field_header_map=None,
                  if field.name in field_names))
 
     # merge the custom field headers into the verbose/raw defaults, if provided
-    _field_header_map = field_header_map or {}
     merged_header_map = name_map.copy()
-    merged_header_map.update(_field_header_map)
+    merged_header_map.update(field_header_map)
     if extra_columns:
         merged_header_map.update(dict((k, k) for k in extra_columns))
     writer.writerow(merged_header_map)

setup.py

@@ -5,7 +5,7 @@
 
 setup(
     name='django-queryset-csv',
-    version='0.2.9',
+    version='0.2.10',
     description='A simple python module for writing querysets to csv',
     long_description=open('README.rst').read(),
     author=author,

test_app/djqscsv_tests/tests/test_csv_creation.py

@@ -27,8 +27,9 @@ class CSVTestCase(TestCase):
     def setUp(self):
         self.qs = create_people_and_get_queryset()
 
-    def assertMatchesCsv(self, csv_file, expected_data):
-        csv_data = csv.reader(csv_file)
+    def csv_match(self, csv_file, expected_data, **csv_kwargs):
+        assertion_results = []
+        csv_data = csv.reader(csv_file, **csv_kwargs)
         iteration_happened = False
         is_first = True
         test_pairs = itertools.izip_longest(csv_data, expected_data,
@@ -39,9 +40,20 @@ def assertMatchesCsv(self, csv_file, expected_data):
                 expected_row = ['\xef\xbb\xbf' + expected_row[0]] + expected_row[1:]
                 is_first = False
             iteration_happened = True
-            self.assertEqual(csv_row, expected_row)
+            assertion_results.append(csv_row == expected_row)
+
+        assertion_results.append(iteration_happened is True)
+
+        return assertion_results
+
+    def assertMatchesCsv(self, *args, **kwargs):
+        assertion_results = self.csv_match(*args, **kwargs)
+        self.assertTrue(all(assertion_results))
+
+    def assertNotMatchesCsv(self, *args, **kwargs):
+        assertion_results = self.csv_match(*args, **kwargs)
+        self.assertFalse(all(assertion_results))
 
-        self.assertTrue(iteration_happened, "The CSV does not contain data.")
 
     def assertQuerySetBecomesCsv(self, qs, expected_data, **kwargs):
         obj = StringIO()
@@ -263,3 +275,25 @@ def test_render_to_csv_response(self):
         self.assertMatchesCsv(response.content.split('\n'),
                               self.FULL_PERSON_CSV_NO_VERBOSE)
 
+
+    def test_render_to_csv_response_other_delimiter(self):
+        response = djqscsv.render_to_csv_response(self.qs,
+                                                  filename="test_csv",
+                                                  use_verbose_names=False,
+                                                  delimiter='|')
+
+        self.assertEqual(response['Content-Type'], 'text/csv')
+        self.assertMatchesCsv(response.content.split('\n'),
+                              self.FULL_PERSON_CSV_NO_VERBOSE,
+                              delimiter="|")
+
+
+    def test_render_to_csv_fails_on_delimiter_mismatch(self):
+        response = djqscsv.render_to_csv_response(self.qs,
+                                                  filename="test_csv",
+                                                  use_verbose_names=False,
+                                                  delimiter='|')
+
+        self.assertEqual(response['Content-Type'], 'text/csv')
+        self.assertNotMatchesCsv(response.content.split('\n'),
+                                 self.FULL_PERSON_CSV_NO_VERBOSE)