add api.save_url

ox/api.py

@@ -1,12 +1,14 @@
 # -*- coding: utf-8 -*-
 # vi:si:et:sw=4:sts=4:ts=4
 # GPL 2011
+from types import MethodType
+import gzip
+import os
+import shutil
 
 from six.moves import http_cookiejar as cookielib
-import gzip
 from six import BytesIO, PY2
 from six.moves import urllib
-from types import MethodType
 
 from . import __version__
 from .utils import json
@@ -122,3 +124,16 @@ class API(object):
             form.add_field('data', json.dumps(data))
         return self._json_request(self.url, form)
 
+    def save_url(self, url, filename, overwrite=False):
+        chunk_size = 16 * 1024
+        if not os.path.exists(filename) or overwrite:
+            dirname = os.path.dirname(filename)
+            if dirname and not os.path.exists(dirname):
+                os.makedirs(dirname)
+            request = urllib.request.Request(url, method='GET')
+            tmpname = filename + '.tmp'
+            with open(tmpname, 'wb') as fd:
+                u = self._opener.open(request)
+                for chunk in iter(lambda: u.read(chunk_size), b''):
+                    fd.write(chunk)
+            shutil.move(tmpname, filename)