Added ignore_conflicts support for #89

Author: palewire

docs/index.rst

@@ -220,6 +220,9 @@ Keyword Argument       Description
                        ``'utf-8'``, and ``'cp437'`` are all valid encoding
                        parameters.
 
+``ignore_conflicts``   Specify True to ignore unique constraint or exclusion
+                       constraint violation errors. The default is False.
+
 ``using``              Sets the database to use when importing data.
                        Default is None, which will use the ``'default'``
                        database.

postgres_copy/copy_from.py

@@ -8,6 +8,7 @@
 import csv
 import logging
 from collections import OrderedDict
+from django.db import NotSupportedError
 from django.db import connections, router
 from django.core.exceptions import FieldDoesNotExist
 from django.contrib.humanize.templatetags.humanize import intcomma
@@ -30,6 +31,7 @@ def __init__(
         force_not_null=None,
         force_null=None,
         encoding=None,
+        ignore_conflicts=False,
         static_mapping=None
     ):
         # Set the required arguments
@@ -53,6 +55,8 @@ def __init__(
         self.force_not_null = force_not_null
         self.force_null = force_null
         self.encoding = encoding
+        self.supports_ignore_conflicts = True
+        self.ignore_conflicts = ignore_conflicts
         if static_mapping is not None:
             self.static_mapping = OrderedDict(static_mapping)
         else:
@@ -70,6 +74,11 @@ def __init__(
         if self.conn.vendor != 'postgresql':
             raise TypeError("Only PostgreSQL backends supported")
 
+        # Check if it is PSQL 9.5 or greater, which determines if ignore_conflicts is supported
+        self.supports_ignore_conflicts = self.is_postgresql_9_5()
+        if self.ignore_conflicts and not self.supports_ignore_conflicts:
+            raise NotSupportedError('This database backend does not support ignoring conflicts.')
+
         # Pull the CSV headers
         self.headers = self.get_headers()
 
@@ -116,6 +125,9 @@ def save(self, silent=False, stream=sys.stdout):
 
         return insert_count
 
+    def is_postgresql_9_5(self):
+        return self.conn.pg_version >= 90500
+
     def get_field(self, name):
         """
         Returns any fields on the database model matching the provided name.
@@ -280,6 +292,17 @@ def post_copy(self, cursor):
     # INSERT commands
     #
 
+    def insert_suffix(self):
+        """
+        Preps the suffix to the insert query.
+        """
+        if self.ignore_conflicts:
+            return """
+                ON CONFLICT DO NOTHING;
+            """
+        else:
+            return ";"
+
     def prep_insert(self):
         """
         Creates a INSERT statement that reorders and cleans up
@@ -291,11 +314,12 @@ def prep_insert(self):
         sql = """
             INSERT INTO "%(model_table)s" (%(model_fields)s) (
             SELECT %(temp_fields)s
-            FROM "%(temp_table)s");
+            FROM "%(temp_table)s")%(insert_suffix)s
         """
         options = dict(
             model_table=self.model._meta.db_table,
             temp_table=self.temp_table_name,
+            insert_suffix=self.insert_suffix()
         )
 
         #

tests/models.py

@@ -112,3 +112,8 @@ def post_insert(self, cursor):
 class SecondaryMockObject(models.Model):
     text = models.CharField(max_length=500)
     objects = CopyManager()
+
+
+class UniqueMockObject(models.Model):
+    name = models.CharField(max_length=500, unique=True)
+    objects = CopyManager()

tests/tests.py

@@ -10,7 +10,8 @@
     LimitedMockObject,
     OverloadMockObject,
     HookedCopyMapping,
-    SecondaryMockObject
+    SecondaryMockObject,
+    UniqueMockObject
 )
 from django.test import TestCase
 from django.db.models import Count
@@ -510,6 +511,18 @@ def test_encoding_save(self):
             date(2012, 1, 1)
         )
 
+    def test_ignore_conflicts(self):
+        UniqueMockObject.objects.from_csv(
+            self.name_path,
+            dict(name='NAME'),
+            ignore_conflicts=True
+        )
+        UniqueMockObject.objects.from_csv(
+            self.name_path,
+            dict(name='NAME'),
+            ignore_conflicts=True
+        )
+
     def test_static_values(self):
         ExtendedMockObject.objects.from_csv(
             self.name_path,