mixcloud-trigger

Run local actions when new items are added to MixCloud.

Example uses include:

• Autoplay newly published things in a new browser window
• Send a notification email
• Feed item to an IM bot
• Tweet a link

Why? Because...

1. I kept missing new uploads by my favourite DJ
2. The MixCloud API makes it easy

You'll probably want to run this from a cron, so it has built-in locking to ensure no more than one instance runs at once.

Requirements

• Python 3 & (probably included) pyvenv. On OSX with homebrew, brew install python3

Features

• Record successful processing so that item won't be touched again
• Retry failed actions on the next run
• Limit to N most recent items

Setup

Needs a virtualenv and a few requirements.

$ cd mixcloud-trigger
$ pyvenv _venv3/
$ . _venv3/bin/activate
$ pip install --upgrade pip
$ pip install -r code/requirements.txt

Configuration

Supports .ini files plus include dirs so config is easy to manage & machine-generate.

Example config tree:

$ tree conf
conf
├── main.conf
└── sources
    └── outsidetrance.conf
    
$ cat cat conf/main.conf
[sources]
sources_dir = conf/sources/

[metadata]
metadata_path = data/

$ cat conf/sources/outsidetrance.conf
[outsidetrance]
item_action = /bin/echo -n {name}
max_items = 3

Global config follows the format:

Section	Key	Default	Description
sources	sources_dir	-	Directory to look in for per-source configs. If it starts with a / it's treated as an absolute path; without and it's relative to the dir the main config file was in.
metadata	metadata_path	-	Directory in which locks & per-source metadata will be stored in SQLite format.

Per-source config must be:

• Within the sources_dir directory. It is not valid to store per-source config in the main config file.
• Filename ending with .conf
• In a section headed with the source name

Inside, the following fields are valid:

Key	Default	Description
max_items	5	Maximum number of items to process in a single run against this feed. Mostly to prevent all-of-the-items-ever getting processed on the first run. Set to 0 if you really want this.
want_types	upload,favorite	Comma-separated list of item types you want to process; others will be ignored. No spaces!
item_action	-	Shell command to be called on every matching item, with item values substituted. See below for format.
all_action	-	Shell command to be called once for this feed with all matching items. Not called if zero items matched. Not yet supported

item_action Format

Python's String.format() is used to interpolate variables into your command for the specific feed item. Variables are:

Variable	Meaning
name	Item name, e.g. "DJ AlexMock's Awesome Mix"
url	Direct MixCloud URL to the item
type	The type of feed item, e.g. upload, favorite
created_time	Time the item was created on MixCloud

Variables are escaped with shlex.quote(). Your command isn't; be careful with it.

Anything /bin/sh can handle, item_action can handle. Your action is written to a temporary file and passed to the local /bin/sh for execution. This means...

• ; can be used to separate multiple commands. e.g. cd /path/to/somewhere; do_something_with {url}
• Pipes work just fine
• Environment vars work - e.g. cd $HOME; do_something_with {url}
• sudo if you want to, but secure it properly

Python's subprocess module has problems handling very large amounts of output from a command. This includes basically anything that prints a progress bar. If you're calling some utility and it has a --quiet option, try to use it.

all_action format

TBA.

Running

$ tree conf
conf
├── main.conf
└── sources
    └── outsidetrance.conf

$ . _venv3/bin/activate

(_venv3) $ ./code/mixtrig.py -h    # display help

(_venv3) $ ./code/mixtrig.py -c examples/conf/main.conf

Implementation Notes

• To ensure no item gets processed twice, once handled media item keys are written to a small SQLite DB is maintained under data/. I tried a simpler approach (ignoring anything from before the script's last run) but it seems there's sometimes a delay between media uploads and the item becoming available, and this meant unseen items could fall before the script's previous run.
• Coloured/indented output with clint
• Some test coverage via basic Python unittest module

Meta

Limitations

• MixCloud's API returns 20 items per page and we don't yet support pagination. Thus if there are more than 20 new items since the last scrape (and you set max_items > 20), the oldest ones will be overlooked.

Coding

Tests

$ python -m unittest discover code/

Todo

• Better input-checking on config
• Make all_action work
• Mutleythreading for shell actions

Pull Requests

Yes please!

License

GPLv3.