| 
  • If you are citizen of an European Union member nation, you may not use this service unless you are at least 16 years old.

  • Stop wasting time looking for files and revisions. Connect your Gmail, DriveDropbox, and Slack accounts and in less than 2 minutes, Dokkio will automatically organize all your file attachments. Learn more and claim your free account.

View
 

SprinklesPy

Page history last edited by Banned User 10 years, 6 months ago

sprinkles 0.4.5

 

 

Intro

Why? Every time I want to release a project I end up thinking, "Gee, wouldn't

it be cool if I had some kind of plugin system so that people could easily

extend the functionality of whatever script I was writing."

 

This library isn't particularly security-minded, it basically scans a

directory you specify and loads up the python files in it to look for

classes that can be imported.

 

Usage

How? This is the more complex of the libraries I've written (I think) but

let's see if I can explain it. What is *does* is fairly simple, what you

need to do to write a plugin is a little more complex.

 

What it does is search a directory, file, module, or package for

importable python files, attempts to import them and then searches them

for classes that implement the ISprinke interface and then, if a

specific filterer has been provided -- usually one of your interface's

implementedBy method, it will make sure the item passes that

filter as well. If that all goes off without a hitch, it returns

a list of classes.

 

To get a list of sprinkles in a directory:

 

 

foo_sprinkles = sprinkles.fromPath(somedir)

 

... from a file

 

 

bar_sprinkles = sprinkles.fromFile(somepath, somefilename)

 

... from a module

 

 

baz_sprinkles = sprinkles.fromModule("some.mod")

 

... or if you happen to have a module already loaded

 

 

baz_sprinkles = sprinkles.fromModule(some.mod)

 

... from a package

 

 

quux_sprinkles = sprinkles.fromPackage("some.package")

 

Now, the more complex part is how to use a sprinkle in some sort of plugin

system. It's not really that complex, in fact it can be superbly simple, but

the actual architecture of a plugin system is something people seem to have

issues with.

 

A simple sprinkle:

 

from sprinkles import implements, ISprinkle

class FooSprinkle(object):

 

implements(ISprinkle)

foo = lambda _: _

 

 

That's all you need for a sprinkle, but this sprinkle probably won't be all

that useful for you.

 

A slightly more useful example:

(taken from workspace)

Let's assume your package has a layout something like:

 

workspace/__init__.py

workspace/core.py

workspace/interfaces.py

workspace/plugins/__init__.py

workspace/plugins/items.py

 

core.py

 

import sprinkles

from workspace.interfaces import IWorkspaceSection

class Workspace(object):

 

def __init__(self):

self.sections = sprinkes.fromPackage("workspace.plugins",

IWorkspaceSection.implementedBy)

 

@classmethod

def fromSystem(cls):

self = cls()

for s in self.sections:

d = s.fromSystem()

self.data[d.name] = d

return self

 

...

 

 

interfaces.py

 

from sprinkles import ISprinkle, implements

class IWorkspaceSection(ISprinkle):

 

@classmethod

def fromSystem(self):

""" initialize a section from the current system """

 

...

 

 

items.py

 

from workspace.interfaces import ISprinkle, implements

class ItemsSection(object):

 

implements(ISprinkle)

@classmethod

def fromSystem(cls):

self = cls()

for s in self.sections:

d = s.fromSystem()

self.data[d.name] = d

return self

...

 

 

 

Module Contents

  • class ISprinkle

 

-- The base interface something must implement to be parsed

 

  • def enableCache
  • def disableCache
  • def flushCache

 

-- Deal with caching of already scanned modules'

 

  • def fromPath
  • def fromFile
  • def fromModule
  • def fromPackage

 

-- Load files from path, file, module or package.

 

 

-- Some helper stuff to use as a plugin management system

 

Todo

Some security stuff, I guess. Probably won't extend much beyond checking

permissions on the file and making sure it isn't world-writable though.

 

Conclusion

Generally, these libraries are provided as an idea about what you may be

interested in doing for yourself, my own way of massaging a few more syntax

niceties into the language I enjoy so much. If you find them useful, I'd love

to hear from you, especially if you have suggestions on additions and

improvements.

 

Author

AndySmith

 

love.

 

Comments (2)

Anonymous said

at 6:01 pm on Apr 18, 2006

Is the plugin method you use in Sprinkles compatible with py2exe single-file packaging?

Anonymous said

at 9:48 pm on Apr 18, 2006

I haven't used py2exe before, but for import from package it looks for the path of the package so that probably won't work, instead try loading from either a path or package outside the exe. I am working on getting it to use the file-access-api stuff, so if py2exe supports that it may eventually work properly

You don't have permission to comment on this page.