intro to pyramid

Intro to Pyramid

Building Fast and Flexible Web Apps

byBrian Cajes

Overview

• What is Pyramid?• Pyramid vs. Other Frameworks• MongoDB Integration• Some Things I've Learned• The Community & Resources• Wrap up & Questions

My Background

• Worked as a Software Engineer at a Financial Services Companyo Large legacy C++ code baseo Hard to maintain and test

• Web apps on the sideo Want flexibility and testability in my web frameworko Pyramid!

• Recently quit the finance job• Turned side project into start-up

What is Pyramid?

• An open source web framework• Easier to create arbitrary web apps• Can be used to build wide array of

applicationsoSimple BlogsoCMSoSocial Web Appso ...

Brief History • Pylons,TurboGears, Django(2005-)

• Repoze.bfg (2008-2010)

o Influenced by Zope* (1998?-)o Chris Mcdonough

• Pylons, Repoze.bfg, TG merge into The Pylons Project (2010)o A collection of web related Python projects under a single

umbrella o Pylons development discontinued o Repoze.bfg renamed to Pyramid o Pyramid currently the main web framework

Setting up Pyramid

$ virtualenv --no-site-packages env

$ cd env

$ bin/easy_install pyramid $ bin/paster create -t pyramid_starter

Hello Worldfrom paste.httpserver import serve from pyramid.config import Configurator from pyramid.response import Response

def hello_world(request): return Response('Hello %(name)s!' \%request.matchdict)

if __name__ == '__main__': config = Configurator() config.add_route('hello', '/hello/{name}') config.add_view(hello_world, route_name='hello') app = config.make_wsgi_app() serve(app, host='0.0.0.0') #serving on 0.0.0.0:8080 view at http://127.0.0.1:8080

#url localhost:8080/hello/bob -> prints 'Hello Bob!' in the browser

#full documentation and tutorials:

#https://docs.pylonsproject.org/projects/pyramid/1.2/

Pyramid's Tenets

• Simplicity • Minimalism

• Documentation

• Reliability

• Openness

• Speed

*https://www.pylonsproject.org/projects/pyramid/about

Simplicity

• "Only pay for what you eat" • Not forced to user any particular technology

o No DBo SQLo MongoDBo All okay

• Easy to set up basic apps

Minimalism

• Relatively small code base (~5000 lines)o Django ~60,000 lines

• Concentrates on common core activities: URL mapping,

templating, security, and serving static assets

Documentation

• Every aspect of the framework is documented • https://docs.pylonsproject.org/

• Coverage is good, but sometimes lacks good examples

o Improving over time

Reliability

• Tested exhaustively • 100% code test coverage

• "If it ain’t tested, it’s broke"

• Source code has good examples of well written tests

Openness

• "As with Python, the Pyramid software is distributed under a permissive open source license."

• Active community

o Main developers Chris McDonough, Ben Bangert, and others respond to question frequently

o Growing library of open source pyramid related projects

Speed

• Core functionality is optimized for very fast execution

• Hardware maybe cheap these days

• The time and energy needed to manage all that hardware is not so cheap

Performance Comparison: String Test

*http://blog.curiasolutions.com/the-great-web-framework-shootout/

Performance Comparison: Templates


Performance Comparison: Templates + DB Queries


Profiling Comparison

Numlines System 22 Pyramid (1.0a9) 34 Bottle (0.8.1) 57 Django (1.02) 96 Flask (0.6) 96 Pylons (0.9.7rc4) 250 Zope2 (2.10 via repoze.zope2) 317 Grok (1.0a1) 398 TurboGears 2 (2.0.3)

*http://plope.com/pyroptimization

Component Architecture

• Advantages of an un-opinionated frameworko Simplicityo Speed out of the boxo Bring in "best of breed" components as you see fit

• Start Pyramid projects with pre-canned scaffolds if you want (eg. SQLAlchemy + URL dispatch)

• Can add components by simply installing python packages

Example: MongoDB Integration• Let's build a simple blog using Pyramid and MongoDB as

the persistent store • Easy enough to wire up mongoDB manually

o start here: https://docs.pylonsproject.org/projects/pyramid_cookbook/dev/mongo.html

• Or start with existing pyramid_mongodb template (ie.

scaffold) by Niall O’Higginso https://github.com/niallo/pyramid_mongodbo easy_install pyramid_mongodbo $ paster create --list-templates Available templates: pyramid_mongodb: pyramid MongoDB

Example: MongoDB Integration• __init__.py : wiring MongoDB to Pyramid

def main(global_config, **settings): """ This function returns a Pyramid WSGI application."""... db_uri = settings['db_uri'] conn = pymongo.Connection(db_uri) config.registry.settings['db_conn'] = conn config.add_subscriber(add_mongo_db, NewRequest)... return config.make_wsgi_app()

def add_mongo_db(event): settings = event.request.registry.settings db = settings['db_conn'][settings['db_name']] event.request.db = db *https://github.com/supr/Blog

*

Example: MongoDB Integration cont.

• blog/views.py: making calls to MongoDB

@view_config( route_name = "home", renderer = "index.mk" )def home(request): entries = request.db.Entries.find({},sort=[("datetime",DESCENDING)]).limit(4) return { 'entries':entries }


• snippet from blog/templates/index.mk

%for entry in entries:<h2>${entry['title'] | h,trim,unicode }</h2><p>Posted by ${entry['username'] | h} on ${entry['datetime'].strftime("%A, %d %B %Y at %I:%M %p")}</p><p>${entry['content'] | h,trim,unicode }</p><p>Tags:${",".join(entry['tags'])}</p>%endfor


• blog/templates/new.mk

<html> <head> <title> New Blog Post </title> </head> <body> <h1> New Post </h1> <form method="POST"> <input type="text" name="title"/> <textarea name="content"></textarea> <input type="text" name="tags"/> <input type="submit" value="Post" name="form.submitted"/> </form> </body></html>


@view_config( route_name = "new", renderer = "new.mk", permission = "new" )def new_entry(request): message = '' if 'form.submitted' in request.params: try: title = request.params['title'] content = request.params['content'] tags = [ x.strip() for x in request.params['tags'].split(",") ] username = authenticated_userid(request) entry = dict( title = title, content = content, tags = tags, username = username, datetime = datetime.now(), ) request.db.Entries.insert(entry) except: message = 'Invalid forum parameters' return dict( message = message ) return {}

Things I've Learned Along the Way

• MongoDB ORM wrappers aren't needed for most use-caseso Pymongo is simple and flexibleo Easy to use within Pyramid

• Nose + Webtest

o Nose - python test managero Webtest - utility that helps with testing python web appso They integrate well with pyramid

Things I've Learned Along the Way

• Pyramid does not force the Model-View-Controller pattern on youo Difficult to internalize if you're used to MVC everywhereo Free yourself from MVCo It's not always the best architecture pattern

• Choices == powero but it can sometimes be overwhelming for beginnerso Tutorials, examples, and documentation improving

Things I've Learned Along the Way cont.

• Two methods of routing requestso URL Dispatch

Simple pattern matching Maps a view function to a URL pattern

o Traversal Analogous to opening a file/directory in your OS's file

system o Stick with URL Dispatch if you're a beginner

• Templating Engine

o Comes with Chameleon and Mako supporto I prefer Mako's syntax

Community

• Community Contributions o Pyramid projects on Github

Best way to learn (other than documentation) o Many pyramid_* packages and continuing to grow

• Google Groups

o http://groups.google.com/group/pylons-discuss • IRC: #pylons on Freenode

Summary

• Pyramid is a fast and flexible web framework• Beats similar web frameworks in many performance metrics • Component Architecture• More choices and flexibility can be good in the long run, but

maybe overwhelming for beginners at first• Learn from and contribute back to the Pylons Community

Thanks for listening!

• Twitter: bcajes• Questlr.com

o Connecting people and real life quests. Share goals, challenges, and stories while inspring others.

o Beta signups

Questions?

intro to pyramid

Technology