Add HTTP range support for file downloads

Author: AndreyVMarkelov

dropbox/__init__.py

@@ -1,5 +1,6 @@
 from __future__ import absolute_import
 
+from ._http import build_range_headers as build_range_headers
 from dropbox.dropbox_client import (  # noqa: F401 # pylint: disable=unused-import
     __version__,
     Dropbox,

dropbox/_http.py

@@ -0,0 +1,43 @@
+def format_byte_range(byte_range):
+    """Format a byte range as an HTTP Range header value."""
+
+    if byte_range is None:
+        return None
+
+    if not isinstance(byte_range, tuple) or len(byte_range) != 2:
+        raise ValueError("byte_range must be a (start, end) tuple")
+
+    start, end = byte_range
+
+    if start is None and end is None:
+        raise ValueError("byte_range must specify start or end")
+
+    for value in (start, end):
+        if value is None:
+            continue
+        if isinstance(value, bool) or not isinstance(value, int):
+            raise TypeError("byte_range values must be non-negative integers")
+        if value < 0:
+            raise ValueError("byte_range values must be non-negative")
+
+    if start is not None and end is not None and end < start:
+        raise ValueError("byte_range end must be greater than or equal to start")
+
+    if start is None:
+        return "bytes=-{}".format(end)
+
+    if end is None:
+        return "bytes={}-".format(start)
+
+    return "bytes={}-{}".format(start, end)
+
+
+def build_range_headers(byte_range):
+    """Build HTTP Range headers for a download request."""
+
+    range_header = format_byte_range(byte_range)
+
+    if range_header is None:
+        return None
+
+    return {"Range": range_header}

dropbox/base.py

@@ -33,7 +33,9 @@ class DropboxBase(object):
     __metaclass__ = ABCMeta
 
     @abstractmethod
-    def request(self, route, namespace, request_arg, request_binary, timeout=None):
+    def request(
+        self, route, namespace, request_arg, request_binary, timeout=None, extra_headers=None
+    ):
         pass
 
     # ------------------------------------------
@@ -1491,13 +1493,14 @@ def files_delete_batch_check(self, async_job_id):
         )
         return r
 
-    def files_download(self, path, rev=None):
+    def files_download(self, path, rev=None, extra_headers=None):
         """
         Download a file from a user's Dropbox.
 
         Route attributes:
             scope: files.content.read
 
+        :param object extra_headers: Additional HTTP headers for this request.
         :param path: The path of the file to download.
         :type path: str
         :param rev: Field is deprecated. Please specify revision in ``path``
@@ -1522,17 +1525,19 @@ def files_download(self, path, rev=None):
             "files",
             arg,
             None,
+            extra_headers=extra_headers,
         )
         return r
 
-    def files_download_to_file(self, download_path, path, rev=None):
+    def files_download_to_file(self, download_path, path, rev=None, extra_headers=None):
         """
         Download a file from a user's Dropbox.
 
         Route attributes:
             scope: files.content.read
 
         :param str download_path: Path on local machine to save file.
+        :param object extra_headers: Additional HTTP headers for this request.
         :param path: The path of the file to download.
         :type path: str
         :param rev: Field is deprecated. Please specify revision in ``path``
@@ -1550,6 +1555,7 @@ def files_download_to_file(self, download_path, path, rev=None):
             "files",
             arg,
             None,
+            extra_headers=extra_headers,
         )
         self._save_body_to_file(download_path, r[1])
         return r[0]

dropbox/dropbox_client.py

@@ -284,7 +284,15 @@ def clone(
             ),
         )
 
-    def request(self, route, namespace, request_arg, request_binary, timeout=None):
+    def request(
+        self,
+        route,
+        namespace,
+        request_arg,
+        request_binary,
+        timeout=None,
+        extra_headers=None,
+    ):
         """
         Makes a request to the Dropbox API and in the process validates that
         the route argument and result are the expected data types. The
@@ -304,6 +312,7 @@ def request(self, route, namespace, request_arg, request_binary, timeout=None):
             server. After the timeout the client will give up on
             connection. If `None`, will use default timeout set on
             Dropbox object.  Defaults to `None`.
+        :param dict extra_headers: Additional HTTP headers for this request.
         :return: The route's result.
         """
 
@@ -338,6 +347,7 @@ def request(self, route, namespace, request_arg, request_binary, timeout=None):
             auth_type,
             request_binary,
             timeout=timeout,
+            extra_headers=extra_headers,
         )
         decoded_obj_result = json.loads(res.obj_result)
         if isinstance(res, RouteResult):
@@ -521,6 +531,7 @@ def request_json_string_with_retry(
         auth_type,
         request_binary,
         timeout=None,
+        extra_headers=None,
     ):
         """
         See :meth:`request_json_object` for description of parameters.
@@ -542,6 +553,7 @@ def request_json_string_with_retry(
                     auth_type,
                     request_binary,
                     timeout=timeout,
+                    extra_headers=extra_headers,
                 )
             except AuthError as e:
                 if e.error and e.error.is_expired_access_token():
@@ -591,6 +603,7 @@ def request_json_string(
         auth_type,
         request_binary,
         timeout=None,
+        extra_headers=None,
     ):
         """
         See :meth:`request_json_string_with_retry` for description of
@@ -611,6 +624,10 @@ def request_json_string(
         url = self._get_route_url(fq_hostname, func_name)
 
         headers = {"User-Agent": self._user_agent}
+
+        if extra_headers:
+            headers.update(extra_headers)
+
         auth_types = auth_type.replace(" ", "").split(",")
         if (USER_AUTH in auth_types or TEAM_AUTH in auth_types) and self._oauth2_access_token:
             headers["Authorization"] = "Bearer %s" % self._oauth2_access_token

generate_base_client.py

@@ -67,7 +67,17 @@ def main():
 
     o = subprocess.check_output(
         (
-            ["python", "-m", "stone.cli", "python_client", dropbox_pkg_path]
+            [
+                "python",
+                "-m",
+                "stone.cli",
+                os.path.join(
+                    os.path.dirname(__file__),
+                    "generator",
+                    "dropbox_python_client.stoneg.py",
+                ),
+                dropbox_pkg_path,
+            ]
             + specs
             + ["-a", "host", "-a", "style", "-a", "auth", "-a", "scope"]
             + [