overwrite file function added

common_helper_mongo/__init__.py

+from .gridfs import overwrite_file
+
+__all__ = [
+           'overwrite_file'
+        ]

common_helper_mongo/gridfs.py

+def overwrite_file(fs, file_name, binary):
+    """
+    overwrite a file by name in gridfs
+
+    :param fs: gridFS instance
+    :type fs: gridFS
+    :param file_name: file to overwrite
+    :type file_name: str
+    :param mongo_curser: MongoDB curser
+    :type mongo_curser: mongo_db_curser
+    :return: None
+    """
+    original_file = fs.find_one({'filename': file_name})
+    if original_file is not None:
+        fs.delete(original_file._id)
+    fs.put(binary, filename=file_name)

tests/test_gridfs.py

+import unittest
+from pymongo import MongoClient
+import gridfs
+
+from common_helper_mongo.gridfs import overwrite_file
+
+
+class TestGridFS(unittest.TestCase):
+
+    def setUp(self):
+        self.mongo_client = MongoClient()
+        self.db = self.mongo_client["common_code_test"]
+        self.fs = gridfs.GridFS(self.db)
+
+    def tearDown(self):
+        self.mongo_client.drop_database(self.db)
+        self.mongo_client.close()
+
+    def testOverwriteFile(self):
+        self.fs.put(b'original', filename="test_file")
+        original_content = self.fs.find_one({'filename': "test_file"}).read()
+        self.assertEqual(original_content, b'original', 'original content not correct')
+        overwrite_file(self.fs, "test_file", b'changed')
+        self.assertEqual(len(self.fs.list()), 1, "original file not deleted")
+        changed_content = self.fs.find_one({'filename': "test_file"}).read()
+        self.assertEqual(changed_content, b'changed', "content not correct")
+
+
+if __name__ == "__main__":
+    # import sys;sys.argv = ['', 'Test.testName']
+    unittest.main()