Merge pull request #58 from azavea/topic/54_56_add_support_for_csv_kwargs

Topic/54 56 add support for csv kwargs

Author: Steve Lamb

.travis.yml

@@ -5,6 +5,11 @@ python:
 env:
   - DJANGO=1.5 RUNNER="coverage run --source=djqscsv" SUCCESS="coveralls"
   - DJANGO=1.6 RUNNER="python" SUCCESS="echo DONE"
+  - DJANGO=1.7 RUNNER="python" SUCCESS="echo DONE"
+matrix:
+  exclude:
+    - python: "2.6"
+      env: DJANGO=1.7 RUNNER="python" SUCCESS="echo DONE"
 install:
   - pip install -r dev_requirements.txt --use-mirrors
   - python setup.py install

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/_csql.py

@@ -6,12 +6,14 @@
 This module may later be officially supported.
 """
 
+
 def _transform(dataset, arg):
     if isinstance(arg, str):
         return (dataset[0].index(arg), arg)
     elif isinstance(arg, tuple):
         return (dataset[0].index(arg[0]), arg[1])
 
+
 def SELECT(dataset, *args):
     # turn the args into indices based on the first row
     index_headers = [_transform(dataset, arg) for arg in args]
@@ -25,10 +27,12 @@ def SELECT(dataset, *args):
                 for datarow in dataset[1:]]
     return results
 
+
 def EXCLUDE(dataset, *args):
     antiargs = [value for index, value in enumerate(dataset[0])
-               if not index in args and not value in args]
+                if index not in args and value not in args]
     return SELECT(dataset, *antiargs)
 
+
 def AS(field, display_name):
     return (field, display_name)

djqscsv/djqscsv.py

@@ -9,22 +9,27 @@
 from django.conf import settings
 if not settings.configured:
     # required to import ValuesQuerySet
-    settings.configure() # pragma: no cover
+    settings.configure()  # pragma: no cover
 
 from django.db.models.query import ValuesQuerySet
 
 from django.utils import six
 
 """ 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
 
 
 def render_to_csv_response(queryset, filename=None, append_datestamp=False,
-                           field_header_map=None, use_verbose_names=True,
-                           field_order=None):
+                           **kwargs):
     """
     provides the boilerplate for making a CSV http response.
     takes a filename or generates one from the queryset's model.
@@ -41,18 +46,28 @@ def render_to_csv_response(queryset, filename=None, append_datestamp=False,
     response['Content-Disposition'] = 'attachment; filename=%s;' % filename
     response['Cache-Control'] = 'no-cache'
 
-    write_csv(queryset, response, field_header_map, use_verbose_names, field_order)
+    write_csv(queryset, response, **kwargs)
 
     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'))
 
@@ -83,8 +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
@@ -96,9 +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)

test_app/test_app/settings.py

@@ -6,6 +6,8 @@
     }
 }
 
+MIDDLEWARE_CLASSES = ()
+
 SECRET_KEY = 'NO_SECRET_KEY'
 
 INSTALLED_APPS = ('djqscsv_tests',)