1 files changed, 79 insertions, 0 deletions
diff --git a/docker/utils/json_stream.py b/docker/utils/json_stream.py
new file mode 100644
index 0000000..f97ab9e
--- /dev/null
+++ b/docker/utils/json_stream.py
@@ -0,0 +1,79 @@
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+import json
+import json.decoder
+
+import six
+
+from ..errors import StreamParseError
+
+
+json_decoder = json.JSONDecoder()
+
+
+def stream_as_text(stream):
+    """Given a stream of bytes or text, if any of the items in the stream
+    are bytes convert them to text.
+    This function can be removed once docker-py returns text streams instead
+    of byte streams.
+    """
+    for data in stream:
+        if not isinstance(data, six.text_type):
+            data = data.decode('utf-8', 'replace')
+        yield data
+
+
+def json_splitter(buffer):
+    """Attempt to parse a json object from a buffer. If there is at least one
+    object, return it and the rest of the buffer, otherwise return None.
+    """
+    buffer = buffer.strip()
+    try:
+        obj, index = json_decoder.raw_decode(buffer)
+        rest = buffer[json.decoder.WHITESPACE.match(buffer, index).end():]
+        return obj, rest
+    except ValueError:
+        return None
+
+
+def json_stream(stream):
+    """Given a stream of text, return a stream of json objects.
+    This handles streams which are inconsistently buffered (some entries may
+    be newline delimited, and others are not).
+    """
+    return split_buffer(stream, json_splitter, json_decoder.decode)
+
+
+def line_splitter(buffer, separator=u'\n'):
+    index = buffer.find(six.text_type(separator))
+    if index == -1:
+        return None
+    return buffer[:index + 1], buffer[index + 1:]
+
+
+def split_buffer(stream, splitter=None, decoder=lambda a: a):
+    """Given a generator which yields strings and a splitter function,
+    joins all input, splits on the separator and yields each chunk.
+    Unlike string.split(), each chunk includes the trailing
+    separator, except for the last one if none was found on the end
+    of the input.
+    """
+    splitter = splitter or line_splitter
+    buffered = six.text_type('')
+
+    for data in stream_as_text(stream):
+        buffered += data
+        while True:
+            buffer_split = splitter(buffered)
+            if buffer_split is None:
+                break
+
+            item, buffered = buffer_split
+            yield item
+
+    if buffered:
+        try:
+            yield decoder(buffered)
+        except Exception as e:
+            raise StreamParseError(e)