Fixed the windows line endings in the CSVCallback. (#11124)

* Fix a bug to write no-need blank line each line on windows

* Fixed the windows line endings in the CSVCallback.

* Converted strings to unicode when using python 2.

* Fixed the unicode issue by opening in binary mode.

* Used six to simplify the compatibility issues.

* Fixed the py2 issue with endline not available for binary mode.

keras/callbacks.py

@@ -12,6 +12,8 @@
 import time
 import json
 import warnings
+import io
+import sys
 
 from collections import deque
 from collections import OrderedDict
@@ -1122,17 +1124,25 @@ def __init__(self, filename, separator=',', append=False):
         self.writer = None
         self.keys = None
         self.append_header = True
-        self.file_flags = 'b' if six.PY2 and os.name == 'nt' else ''
+        if six.PY2:
+            self.file_flags = 'b'
+            self._open_args = {}
+        else:
+            self.file_flags = ''
+            self._open_args = {'newline': '\n'}
         super(CSVLogger, self).__init__()
 
     def on_train_begin(self, logs=None):
         if self.append:
             if os.path.exists(self.filename):
                 with open(self.filename, 'r' + self.file_flags) as f:
                     self.append_header = not bool(len(f.readline()))
-            self.csv_file = open(self.filename, 'a' + self.file_flags)
+            mode = 'a'
         else:
-            self.csv_file = open(self.filename, 'w' + self.file_flags)
+            mode = 'w'
+        self.csv_file = io.open(self.filename,
+                                mode + self.file_flags,
+                                **self._open_args)
 
     def on_epoch_end(self, epoch, logs=None):
         logs = logs or {}
@@ -1156,9 +1166,12 @@ def handle_value(k):
         if not self.writer:
             class CustomDialect(csv.excel):
                 delimiter = self.sep
-
+            fieldnames = ['epoch'] + self.keys
+            if six.PY2:
+                fieldnames = [unicode(x) for x in fieldnames]
             self.writer = csv.DictWriter(self.csv_file,
-                                         fieldnames=['epoch'] + self.keys, dialect=CustomDialect)
+                                         fieldnames=fieldnames,
+                                         dialect=CustomDialect)
             if self.append_header:
                 self.writer.writeheader()
 

tests/keras/test_callbacks.py

@@ -556,11 +556,15 @@ def make_model():
 
     # case 3, reuse of CSVLogger object
     model.fit(X_train, y_train, batch_size=batch_size,
-              validation_data=(X_test, y_test), callbacks=cbks, epochs=1)
+              validation_data=(X_test, y_test), callbacks=cbks, epochs=2)
 
     import re
     with open(filepath) as csvfile:
-        output = " ".join(csvfile.readlines())
+        list_lines = csvfile.readlines()
+        for line in list_lines:
+            assert line.count(sep) == 4
+        assert len(list_lines) == 5
+        output = " ".join(list_lines)
         assert len(re.findall('epoch', output)) == 1
 
     os.remove(filepath)