Skip to main content

Learning new things

It's important for every developer to learn new things. It's very easy to stay in your comfort zone, only take on tasks that you know exactly how to tackle and that can be very efficient as well - if there is something you're good at it makes sense to play to your strengths. The trouble is you don't gain experience without trying something new - go out of your comfort zone.

I've been wanting to try out the asyncio module in Python 3, and have also been meaning to try out Go for a long time. I've also been playing around with Xmpp - an open standard for messaging and presence, used for instant messaging systems - this seems like it might provide a good proving ground for comparing different programming languages. I know, I know, none of these are particularly new, but they're new to me.

My goal is to implement simple chat bots in both Python 3 and Go so I can compare and contrast the two. I'll cover this in several posts over the next weeks, with the full source available on GitHub. I'll write these posts in the style of tutorials - hopefully somebody out there will find them useful.

I'll start with a simple echo bot - all it does is echo back anything it receives. It's a simple feature set, but is very useful for getting started with Xmpp. A more interesting bot is what I've dubbed the jumper bot - it jumps between chat groups, saying a few phrases before moving on to the next group. The interesting bit for implementing it in Python 3 or Go is that I'll have one process running multiple bots, making use of the asynchronous features of each language.

In my next post I'll go over the steps of setting up an Xmpp server to experiment with, and start poking at it with some Python code, as preparation for starting the coding of the bots.



Comments

Popular posts from this blog

Mnesia queries

I've added search and trim to my expiring records module in Erlang. This started out as an in-memory key/value store, that I then migrated over to using Mnesia and eventually to a replicated Mnesia table. The fetch/1 function is already doing a simple query, with match_object. Result=mnesia:match_object(expiring_records, #record{key=Key, value='_', expires_at='_'}, read) The three parameters there are the name of the table - expiring_records, the matching pattern and the lock type (read lock). The fetch/1 function looks up the key as it was added to the table with store/3. If the key is a tuple, we can also do a partial match: Result=mnesia:match_object(expiring_records, #record{key= {'_', "bongo"}, value='_', expires_at='_'}, read) I've added a search/1 function the module that takes in a matching pattern and returns a list of items where the key matches the pattern. Here's the test for the search/1 function: search_partial_…

Working with Xmpp in Python

Xmpp is an open standard for messaging and presence, used for instant messaging systems. It is also used for chat systems in several games, most notably League of Legends made by Riot Games.

Xmpp is an xml based protocol. Normally you work with xml documents - with Xmpp you work with a stream of xml elements, or stanzas - see https://tools.ietf.org/html/rfc3920 for the full definitions of these concepts. This has some implications on how best to work with the xml.

To experiment with Xmpp, let's start by installing a chat server based on Xmpp and start interacting with it. For my purposes I've chosen Prosody - it's nice and simple to install, especially on macOS with Homebrew:

brew tap prosody/prosody
brew install prosody

Start the server with prosodyctl - you may need to edit the configuration file (/usr/local/etc/prosody/prosody.cfg.lua on the Mac), adding entries for prosody_user and pidfile. Once the server is up and running we can start poking at it to get a feel for h…

Expiring records in Erlang

I'm continuing my experiments with Erlang - this time trying out gen_server with a simple key/value store with a twist - the values have an expiration date. As a first iteration I'm simply using a dictionary to store the values, and only expiring records when they are looked up. My plan is to extend this later on so that this can be a global key/value store across multiple Erlang nodes but for now I'm focusing on two things - get something going using gen_server, and try out the common_test testing framework. The code is here: https://github.com/snorristurluson/erl-expiring-records Let's first take a look at a couple of the test functions, to show the usage of this: get_non_expired_record(Config) ->Pid=?config(pid, Config), Record= {"bingo", "bongo", erlang:system_time(second) +3600}, ok=gen_server:call(Pid, {add, Record}), {ok, "bongo"} =gen_server:call(Pid, {fetch, "bingo"}). get_expired_record(Config) ->Pid=…