StreamChatAgent

YouTube chat poller which can get massages very smothly by using internal queue.

The user of this library can

• receive YouTube chat messages continiously by registering callback.
• natively obtain high performance by using internal queue.

How to install

You can select from following ways.

Install from PyPI

• Install package to your environment.
  

  $ pip install streamchat-agent
  

Install from GitHub repository

• Clone this repository.
  

  $ clone https://github.com/GeneralYadoc/StreamChatAgent.git
  

• Change directory to the root of the repository.
  

  $ cd StreamChatAgent
  

• Install package to your environment.
  

  $ pip install .
  

How to use

• Sample codes exists here
  

  import sys
  import re
  import StreamChatAgent as sca  # Import this.
  
  # callback for getting YouTube chat item
  # You can implement several processes in it.
  # This example prints datetime, ahthor name, message, of each item.
  def get_item_cb(c):
    print(f"{c.datetime} [{c.author.name}]- {c.message}")
  
  # pre putting queue filter
  # You can edit YouTube chat item before putting internal queue.
  # You can avoid putting internal queue by returning None.
  # This example removes item whose message consists of stamps only.
  def pre_filter_cb(c):
    return None if re.match(r'^(:[^:]+:)+$', c.message) else c
  
  # post getting queue filter
  # You can edit YouTube chat item after popping internal queue.
  # You can avoid sending item to get_item_cb by returning None.
  # This example removes stamps from message of item.
  def post_filter_cb(c):
    c.message = re.sub(r':[^:]+:','', c.message)
    return c
  
  # Video ID is given from command line in this example.
  if len(sys.argv) <= 1:
    exit(0)
  
  # Create StreamChatAgent instance.
  params = sca.params(
    video_id = sys.argv[1],
    get_item_cb = get_item_cb,
    pre_filter_cb = pre_filter_cb,
    post_filter_cb = post_filter_cb
  )
  agent = sca.StreamChatAgent( params )
  
  # Start async getting YouTube chat items.
  # Then get_item_cb is called continuosly.
  agent.start()
  
  # Wait any key inputted from keyboad.
  input()
  
  # Finish getting items.
  # Internal thread will stop soon.
  agent.disconnect()
  
  # Wait terminating internal threads.
  agent.join()
  
  del agent

• Output of the sample

  % python3 ./sample.py MB57rMXXXXs
  2023-05-19 05:21:26 [John]- Hello!
  2023-05-19 05:21:27 [Kelly]- Hello everyone!
  2023-05-19 05:21:27 [Taro]- Welcome to our stream.
  

Params given to Constructor

• StreamChatAgent object can be configured with following params given to constructor.

  name	description	default
  video_id	String following after 'v=' in url of target YouTube live	-
  get_item_cb	Chat items are thrown to this callback	None
  pre_filter_cb	Filter set before internal queue	None
  post_filter_cb	Filter set between internal queue and get_item_cb	None
  max_queue_size	Max slots of internal queue (0 is no limit)	1000
  interval_sec	Polling interval of picking up items from YouTube	0.01 [sec]

Methods

start()

• Start polling and calling user callbacks asyncronously.
• No arguments required, nothing returns.

join()

• Wait terminating internal threads kicked by start().
• No arguments required, nothing returns.

connect()

• Start polling and calling user callbacks syncronously.
• Lines following the call of the method never executen before terminate of internal threads.
• No arguments required, nothing returns.

disconnect()

• Request to terminate polling and calling user callbacks.
• Internal process will be terminated soon after.
• No arguments required, nothing returns.

And other threading.Thread public pethods are available.

Callbacks

get_item_cb

• Callback for getting YouTube chat items.
• You can implement several processes in it.
• YouTube chat item is thrown as an argument.
• It's not be assumed that any values are returned.

pre_filter_cb

• pre putting queue filter.
• YouTube chat item is thrown as an argument.
• You can edit YouTube chat items before putting internal queue.
• It's required that edited chat item is returned.
• You can avoid putting internal queue by returning None.

post_filter_cb

• post getting queue filter
• You can edit YouTube chat items after popping internal queue.
• It's required that edited chat item is returned.
• You can avoid sending item to get_item_cb by returning None.

Type of YouTube Chat item

• Please refer pytchat README

Concept of design

• Putting thread is separated from getting thread in order to avoid locking polling.
  Unexpected sleep of pytchat may reduce by ths approach.
• If internal queue is full when putting thread try to push new item, oldest item is removed from the queue before pushing.

Links

StreamingChaatAgent uses following libraries internally.

• pytchat   Python library for fetching youtube live chat.