diff env/lib/python3.9/site-packages/requests_toolbelt/streaming_iterator.py @ 0:4f3585e2f14b draft default tip

"planemo upload commit 60cee0fc7c0cda8592644e1aad72851dec82c959"

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/env/lib/python3.9/site-packages/requests_toolbelt/streaming_iterator.py	Mon Mar 22 18:12:50 2021 +0000
@@ -0,0 +1,116 @@
+# -*- coding: utf-8 -*-
+"""
+
+requests_toolbelt.streaming_iterator
+====================================
+
+This holds the implementation details for the :class:`StreamingIterator`. It
+is designed for the case where you, the user, know the size of the upload but
+need to provide the data as an iterator. This class will allow you to specify
+the size and stream the data without using a chunked transfer-encoding.
+
+"""
+from requests.utils import super_len
+
+from .multipart.encoder import CustomBytesIO, encode_with
+
+
+class StreamingIterator(object):
+
+    """
+    This class provides a way of allowing iterators with a known size to be
+    streamed instead of chunked.
+
+    In requests, if you pass in an iterator it assumes you want to use
+    chunked transfer-encoding to upload the data, which not all servers
+    support well. Additionally, you may want to set the content-length
+    yourself to avoid this but that will not work. The only way to preempt
+    requests using a chunked transfer-encoding and forcing it to stream the
+    uploads is to mimic a very specific interace. Instead of having to know
+    these details you can instead just use this class. You simply provide the
+    size and iterator and pass the instance of StreamingIterator to requests
+    via the data parameter like so:
+
+    .. code-block:: python
+
+        from requests_toolbelt import StreamingIterator
+
+        import requests
+
+        # Let iterator be some generator that you already have and size be
+        # the size of the data produced by the iterator
+
+        r = requests.post(url, data=StreamingIterator(size, iterator))
+
+    You can also pass file-like objects to :py:class:`StreamingIterator` in
+    case requests can't determize the filesize itself. This is the case with
+    streaming file objects like ``stdin`` or any sockets. Wrapping e.g. files
+    that are on disk with ``StreamingIterator`` is unnecessary, because
+    requests can determine the filesize itself.
+
+    Naturally, you should also set the `Content-Type` of your upload
+    appropriately because the toolbelt will not attempt to guess that for you.
+    """
+
+    def __init__(self, size, iterator, encoding='utf-8'):
+        #: The expected size of the upload
+        self.size = int(size)
+
+        if self.size < 0:
+            raise ValueError(
+                'The size of the upload must be a positive integer'
+                )
+
+        #: Attribute that requests will check to determine the length of the
+        #: body. See bug #80 for more details
+        self.len = self.size
+
+        #: Encoding the input data is using
+        self.encoding = encoding
+
+        #: The iterator used to generate the upload data
+        self.iterator = iterator
+
+        if hasattr(iterator, 'read'):
+            self._file = iterator
+        else:
+            self._file = _IteratorAsBinaryFile(iterator, encoding)
+
+    def read(self, size=-1):
+        return encode_with(self._file.read(size), self.encoding)
+
+
+class _IteratorAsBinaryFile(object):
+    def __init__(self, iterator, encoding='utf-8'):
+        #: The iterator used to generate the upload data
+        self.iterator = iterator
+
+        #: Encoding the iterator is using
+        self.encoding = encoding
+
+        # The buffer we use to provide the correct number of bytes requested
+        # during a read
+        self._buffer = CustomBytesIO()
+
+    def _get_bytes(self):
+        try:
+            return encode_with(next(self.iterator), self.encoding)
+        except StopIteration:
+            return b''
+
+    def _load_bytes(self, size):
+        self._buffer.smart_truncate()
+        amount_to_load = size - super_len(self._buffer)
+        bytes_to_append = True
+
+        while amount_to_load > 0 and bytes_to_append:
+            bytes_to_append = self._get_bytes()
+            amount_to_load -= self._buffer.append(bytes_to_append)
+
+    def read(self, size=-1):
+        size = int(size)
+        if size == -1:
+            return b''.join(self.iterator)
+
+        self._load_bytes(size)
+        return self._buffer.read(size)