Can now handle read only classifier data as well

talon/signature/learning/classifier.py

@@ -7,8 +7,6 @@ body belongs to the signature.
 
 from __future__ import absolute_import
 
-import pickle
-
 from numpy import genfromtxt
 from sklearn.externals import joblib
 from sklearn.svm import LinearSVC
@@ -32,19 +30,37 @@ def train(classifier, train_data_filename, save_classifier_filename=None):
 
 def load(saved_classifier_filename, train_data_filename):
     """Loads saved classifier. """
-    try:
-        return joblib.load(saved_classifier_filename)
-    except ValueError:
-        # load python 2 pickle format with python 3, and save it permissions allowing
     import sys
-        kwargs = {}
     if sys.version_info > (3, 0):
-            kwargs["encoding"] = "latin1"
-
-        loaded = pickle.load(open(saved_classifier_filename, 'rb'), **kwargs)
-        try:
-            joblib.dump(loaded, saved_classifier_filename, compress=True)
-        except Exception:
-            pass
+        return load_compat(saved_classifier_filename)
 
     return joblib.load(saved_classifier_filename)
+
+
+def load_compat(saved_classifier_filename):
+    import os
+    import pickle
+    import tempfile
+
+    # we need to switch to the data path to properly load the related _xx.npy files
+    cwd = os.getcwd()
+    os.chdir(os.path.dirname(saved_classifier_filename))
+
+    # convert encoding using pick.load and write to temp file which we'll tell joblib to use
+    pickle_file = open(saved_classifier_filename, 'rb')
+    classifier = pickle.load(pickle_file, encoding='latin1')
+
+    try:
+        # save our conversion if permissions allow
+        joblib.dump(classifier, saved_classifier_filename)
+    except Exception:
+        # can't write to classifier, use a temp file
+        tmp = tempfile.SpooledTemporaryFile()
+        joblib.dump(classifier, tmp)
+        saved_classifier_filename = tmp
+
+    # important, use joblib.load before switching back to original cwd
+    jb_classifier = joblib.load(saved_classifier_filename)
+    os.chdir(cwd)
+
+    return jb_classifier