open source

vocode/streaming/utils/sse_client.py

@@ -0,0 +1,236 @@
+"""
+A port of sseclient (https://pypi.org/project/sseclient/) that allows you to get server-side events with a POST request
+
+Copyright (c) 2015 Brent Tubbs 
+
+
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE."""
+#
+# Distributed under the terms of the MIT license.
+#
+from __future__ import unicode_literals
+
+import codecs
+import re
+import time
+import warnings
+
+import six
+
+import requests
+
+__version__ = "0.0.27"
+
+# Technically, we should support streams that mix line endings.  This regex,
+# however, assumes that a system will provide consistent line endings.
+end_of_field = re.compile(r"\r\n\r\n|\r\r|\n\n")
+
+
+class SSEClient(object):
+    def __init__(
+        self,
+        method,
+        url,
+        last_id=None,
+        retry=3000,
+        session=None,
+        chunk_size=1024,
+        **kwargs
+    ):
+        self.url = url
+        self.method = method
+        self.last_id = last_id
+        self.retry = retry
+        self.chunk_size = chunk_size
+
+        # Optional support for passing in a requests.Session()
+        self.session = session
+
+        # Any extra kwargs will be fed into the requests.get call later.
+        self.requests_kwargs = kwargs
+
+        # The SSE spec requires making requests with Cache-Control: nocache
+        if "headers" not in self.requests_kwargs:
+            self.requests_kwargs["headers"] = {}
+        self.requests_kwargs["headers"]["Cache-Control"] = "no-cache"
+
+        # The 'Accept' header is not required, but explicit > implicit
+        self.requests_kwargs["headers"]["Accept"] = "text/event-stream"
+
+        # Keep data here as it streams in
+        self.buf = ""
+
+        self._connect()
+
+    def _connect(self):
+        if self.last_id:
+            self.requests_kwargs["headers"]["Last-Event-ID"] = self.last_id
+
+        # Use session if set.  Otherwise fall back to requests module.
+        requester = self.session or requests
+        self.resp = requester.request(
+            self.method, self.url, stream=True, **self.requests_kwargs
+        )
+        self.resp_iterator = self.iter_content()
+        encoding = self.resp.encoding or self.resp.apparent_encoding
+        self.decoder = codecs.getincrementaldecoder(encoding)(errors="replace")
+
+        # TODO: Ensure we're handling redirects.  Might also stick the 'origin'
+        # attribute on Events like the Javascript spec requires.
+        self.resp.raise_for_status()
+
+    def iter_content(self):
+        def generate():
+            while True:
+                if (
+                    hasattr(self.resp.raw, "_fp")
+                    and hasattr(self.resp.raw._fp, "fp")
+                    and hasattr(self.resp.raw._fp.fp, "read1")
+                ):
+                    chunk = self.resp.raw._fp.fp.read1(self.chunk_size)
+                else:
+                    # _fp is not available, this means that we cannot use short
+                    # reads and this will block until the full chunk size is
+                    # actually read
+                    chunk = self.resp.raw.read(self.chunk_size)
+                if not chunk:
+                    break
+                yield chunk
+
+        return generate()
+
+    def _event_complete(self):
+        return re.search(end_of_field, self.buf) is not None
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        while not self._event_complete():
+            try:
+                next_chunk = next(self.resp_iterator)
+                if not next_chunk:
+                    raise EOFError()
+                self.buf += self.decoder.decode(next_chunk)
+
+            except (
+                StopIteration,
+                requests.RequestException,
+                EOFError,
+                six.moves.http_client.IncompleteRead,
+            ) as e:
+                print(e)
+                time.sleep(self.retry / 1000.0)
+                self._connect()
+
+                # The SSE spec only supports resuming from a whole message, so
+                # if we have half a message we should throw it out.
+                head, sep, tail = self.buf.rpartition("\n")
+                self.buf = head + sep
+                continue
+
+        # Split the complete event (up to the end_of_field) into event_string,
+        # and retain anything after the current complete event in self.buf
+        # for next time.
+        (event_string, self.buf) = re.split(end_of_field, self.buf, maxsplit=1)
+        msg = Event.parse(event_string)
+
+        # If the server requests a specific retry delay, we need to honor it.
+        if msg.retry:
+            self.retry = msg.retry
+
+        # last_id should only be set if included in the message.  It's not
+        # forgotten if a message omits it.
+        if msg.id:
+            self.last_id = msg.id
+
+        return msg
+
+    if six.PY2:
+        next = __next__
+
+
+class Event(object):
+    sse_line_pattern = re.compile("(?P<name>[^:]*):?( ?(?P<value>.*))?")
+
+    def __init__(self, data="", event="message", id=None, retry=None):
+        assert isinstance(data, six.string_types), "Data must be text"
+        self.data = data
+        self.event = event
+        self.id = id
+        self.retry = retry
+
+    def dump(self):
+        lines = []
+        if self.id:
+            lines.append("id: %s" % self.id)
+
+        # Only include an event line if it's not the default already.
+        if self.event != "message":
+            lines.append("event: %s" % self.event)
+
+        if self.retry:
+            lines.append("retry: %s" % self.retry)
+
+        lines.extend("data: %s" % d for d in self.data.split("\n"))
+        return "\n".join(lines) + "\n\n"
+
+    @classmethod
+    def parse(cls, raw):
+        """
+        Given a possibly-multiline string representing an SSE message, parse it
+        and return a Event object.
+        """
+        msg = cls()
+        for line in raw.splitlines():
+            m = cls.sse_line_pattern.match(line)
+            if m is None:
+                # Malformed line.  Discard but warn.
+                warnings.warn('Invalid SSE line: "%s"' % line, SyntaxWarning)
+                continue
+
+            name = m.group("name")
+            if name == "":
+                # line began with a ":", so is a comment.  Ignore
+                continue
+            value = m.group("value")
+
+            if name == "data":
+                # If we already have some data, then join to it with a newline.
+                # Else this is it.
+                if msg.data:
+                    msg.data = "%s\n%s" % (msg.data, value)
+                else:
+                    msg.data = value
+            elif name == "event":
+                msg.event = value
+            elif name == "id":
+                msg.id = value
+            elif name == "retry":
+                msg.retry = int(value)
+
+        return msg
+
+    def __str__(self):
+        return self.data