aio_chat

This demonstrates a very simple application that uses the following components running within the asphalt framework:

• jinja2 (asphalt_templating)
• sqlalchemy (asphalt_sqlalchemy)
• redis (asphalt_redis)
• aiohttp (custom)
• pubsub (custom)

The purpose of this demo is to show a very basic Create / Retrieve web application, where the data is persistently stored in a Postgres database, and the additions are published to a Redis pubsub channel.

Instructions

Create database

Assuming you have PostgreSQL installed, issue this command:

createdb aio_chat

Install

1. create a virtual environment:

python -m venv env

2. activate virtual environment:

src env/bin/activate

3. install package:

pip install -e .

Update configuration

Sane defaults are assumed by the development config, but you can update them accordingly.

aio_chat/development.yaml

Serve

Execute the following command:

road serve development.yaml

Now, in your browser visit http://localhost:9000.

Shell

Simply call road shell development.yaml. Note that the aiohttp (and all services) are actively running in the background. This means that if you want to have a CLI interface and a web interface at the same time, you've got it! Practically, other services might be helpful - like access to redis.

If you'd like to run coroutines on the loop, use this format:

call_async(my_coroutine, arg1, arg2)

For example, to run the server and a shell, run this command:

road serve development.yaml

And visit http://localhost:9001 in your browser.

Complex Example

You can explore all these techniques by running by following this more complex messsaging example. In this example we'll run the server on localhost:9000 and as well as a shell. The website will receive new message entries as we create them in the shell.

1. in one terminal run (note, this will run on port 9000 by default):

road serve development.yaml

2. in a second terminal run (note, this will run a server on port 9001 by default):

road shell development.yaml

3. open up a browser window to localhost:9000.

4. in your tab running an interactive terminal, execute the following:

msg = _m.Message(text='hello world')
sql.add(msg)
sql.commit()

5. watch as your browser updates with the new message.