Ruby on Rails: Tasty Burgers

Tasty Burgers

ZOMG GOOD MORNING!

HAPPY WEDNESDAY!

PEW PEW PEW!

http://tenderlovemaking.com/ railsconf2010.pdf

Aaron Patterson

@tenderlove

Seattle.rb

Ruby-Core Team

AT&T, AT&T logo and all AT&T related marks are trademarks of AT&T Intellectual Property and/or AT&T affiliated companies.

We’re Hiring!

Rails 4*

Rails 4* • Ponies • Unicorns • Venture Capital

*Disclaimer Some of the things I say may not be true.

Why I’m Here* *The following events may not have actually happened

One Day...

jogging

Hello! This is @tenderlove, who is this?

This is Chad Fowler!

AH! Chad Flower, the famous ﬂorist?

Famous Florist: Chad Flower

Chad Fouler the Baseball player?

Baseball Player: Chad Fouler

Chad Flounder the Fish Whisperer?

Fish Whisperer: Chad Flounder

Wait. Yes this is Chad Flounder, Fish Whisperer.

But I'm calling on behalf of Chad Fowler, Ruby Programmer.

To invite you to RailsConf.

I accept.

The Next Day

At Work

I'll need your bio, afﬁliation, and so on. I would also love a recent head shot of you. 300 dpi, 3 " minimum is preferable.

Professional

2 min later...

Erm. Nice mullet. Is that really you?

You know that means I'm going to require you to have that mullet at RailsConf.

Time to get Professional

Rails This is RailsConf right?

Ingredients

ERb SQLITE RACK RAILS YAML

Using our Ingredients

Twisting Software

CONFUSION

INTRIGUE

INSPIRED

Better ingredients, better burgers. Guaranteed

TOPICS OF DOOM • SQLite • ERb • Rack • YAML

SQLite3-Ruby

SQLite3-Ruby • Adapter for SQLite3 database • Originally by Jamis Buck • SWIG

Relationship with Rails

Default Database

class Foo < AR::Base; end Foo.ﬁnd(:all, :conditions => {...}) Foo.ﬁnd(:all, :conditions => [ ‘x = ?’, 20 ])

ActionView ActionController ActiveRecord SQLite3-Ruby

ActiveRecord SQLite3-Ruby

AR::Base SQLite3 Adapter Connection Pool

SQLite3Adapter SQLite3-Ruby

Outside Rails

Establishing a Connection require 'sqlite3' connection = SQLite3::Database.new('ﬁle.sqlite3')

In Memory Database Pro Tip require 'sqlite3' connection = SQLite3::Database.new(':memory:')

database.yml development: adapter: sqlite3 database: ':memory:'

Making a Query connection.execute('CREATE TABLE foo(id INTEGER)') connection.execute('INSERT INTO foo (id) VALUES (?)', [10])

Preparing a Statement stmt = connection.prepare('SELECT * FROM foo WHERE id = ?') stmt.bind_param(1, 10) stmt.each do |row| p row end

Why Prepare a Statement?

Statements can be cached

Can improve database performance

Rails Caveats

Parameter Substitution

User.ﬁnd(10)

SELECT * FROM users WHERE id = ?

stmt = get_cached_stmt || connection.prepare( 'SELECT * FROM users WHERE id = ?' ) stmt.execute(10)

WRONG stmt = get_cached_stmt || connection.prepare( 'SELECT * FROM users WHERE id = ?' ) stmt.execute(10)

connection.execute( 'SELECT * FROM users WHERE id = 10' )

No Prepared Statement Support :-(

Room for Improvement?

Twisting SQLite3

• Step 1: Read the API • Step 2: Write your code • Step 3: Annoy your friends (or proﬁt)

Step 1: Read the API struct sqlite3_vfs { int iVersion; /* Structure version number */ int szOsFile; /* Size of subclassed sqlite3_file */ int mxPathname; /* Maximum file pathname length */ sqlite3_vfs *pNext; /* Next registered VFS */ const char *zName; /* Name of this virtual file system */ void *pAppData; /* Pointer to application-specific data */ int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, int flags, int *pOutFlags); int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); void (*xDlClose)(sqlite3_vfs*, void*); int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); int (*xSleep)(sqlite3_vfs*, int microseconds); int (*xCurrentTime)(sqlite3_vfs*, double*); int (*xGetLastError)(sqlite3_vfs*, int, char *); /* New fields may be appended in figure versions. The iVersion ** value will increment whenever this happens. */ };

IO Hooks

Step 2: Write our Code

static int rbFile_close(sqlite3_file * ctx) { rubyFilePtr rfile = (rubyFilePtr)ctx; VALUE file = rfile->file; rb_funcall(file, rb_intern("close"), 0); return SQLITE_OK; }

class VFS < SQLite3::VFS def open(name, ﬂags) OurFile.new(name, ﬂags) end end class OurFile def read(...); ... end def write(...); ... end end

Anything can store a SQLite Database

__END__ + DATA

class EvilVFS < SQLite3::VFS def open name, flags DATABase.new name, flags end end class DATABase < SQLite3::VFS::File def initialize name, flags super @store = File.open(name, File::RDWR | File::CREAT) @offset = 0 if File.expand_path(__FILE__) == name @store.seek DATA.pos @offset = DATA.pos end end def close @store.close end def read amt, offset @store.seek(offset + @offset) @store.read amt end def write data, offset @store.seek(offset + @offset) @store.write data end def sync opts @store.fsync end def file_size

SQLite3.vfs_register(EvilVFS.new) db = SQLite3::Database.new(__FILE__, nil, 'EvilVFS') db.execute(<<-eosql) create table if not exists users(id integer primary key, name string) eosql 100.times { db.execute(<<-eosql, 'tenderlove') insert into users(name) values (?) eosql } p db.execute('select count(*) from users') __END__

Step 3: Proﬁt?

Get the Code! http://gist.github.com/319224/

What's New in SQLite3-Ruby?

Fun Stuff!! • Ruby 1.9 Encoding support • 1000x faster (or something)

Encodings require 'sqlite3' db = SQLite3::Database.new(':memory:') db.execute('CREATE TABLE foo(id INTEGER, name VARCHAR)') db.execute('INSERT INTO foo (id, name) VALUES (?,?)',[10,'hello world']) rows = db.execute('SELECT name FROM foo') p rows.first.first.encoding # => #<Encoding:UTF-8> Encoding.default_internal = 'EUC-JP' rows = db.execute('SELECT name FROM foo') p rows.first.first.encoding # => #<Encoding:EUC-JP>

Speed! (on selects) 1.2.5 1.3.0 1000 100 10 1 0.1 0.01 500 1000 1500 2000 2500 3000 3500

ERb • Masatoshi SEKI • Template System • Ruby 1.8 and 1.9

app/views/**/*.html.erb

render('users/show')

Template Registration class Something::ERB < AV::Template::Handler def render(template, *args) ... body end end ActionView::Template.register_template_handler( :erb, Something::ERB )

AV Resolver render() Something::ERB

Something::ERB ERb

Outside Rails

require 'erb' erb = ERB.new(File.read(__FILE__)) puts erb.result(binding) __END__ Hello world! <%= 10 + 100 %>

Output require 'erb' erb = ERB.new(File.read(__FILE__)) puts erb.result(binding) __END__ Hello world! 110

require 'erb' erb = ERB.new(File.read(__FILE__)) puts erb.result(binding) __END__ Hello world! <%= 10 + 100 %>

Template Source require 'erb' erb = ERB.new(File.read(__FILE__)) puts erb.src __END__ Hello world! <%= 10 + 100 %>

Output _erbout = ''; _erbout.concat "require 'erb'nnerb = ERB.new(File.read(__FILE__))nputs erb.srcn n__END__nHello world! " ; _erbout.concat(( 10 + 100 ).to_s); _erbout.concat "n" ; _erbout

Output Buffer require 'erb' erb = ERB.new(File.read(__FILE__), nil, nil, '@foo') puts erb.src __END__ Hello world! <%= 10 + 100 %>

Output @foo = ''; @foo.concat "require 'erb'nnerb = ERB.new(File.read(__FILE__), nil, nil, '@foo')nputs erb.srcnn__END__nHello world! " ; @foo.concat(( 10 + 100 ).to_s); @foo.concat "n" ; @foo

Twisting ERb

ERb Memory Footprint

IO Input

mmap allocate memory, or map ﬁles or devices into memory

gem install mmap

Mmap.new(__FILE__)

IO input require 'erb' require 'rubygems' require 'mmap' erb = ERB.new(Mmap.new(__FILE__), nil, nil, '@foo') erb.result(binding) puts @foo __END__ Hello world! <%= 10 + 100 %>

IO Output

Our Problem def set_eoutvar(compiler, eoutvar) ... cmd = [] cmd.push "#{eoutvar} = ''" compiler.pre_cmd = cmd ... end

A Solution class ERB::Compiler def pre_cmd= x; end end

Source Output (before) @foo = ''; @foo.concat "require 'erb'nrequire 'rubygems'nrequire 'mmap'nnclass ERB::Compilern def pre_cmd= x; endnend nnerb = ERB.new(Mmap.new(__FILE__), nil, nil, '@foo')nputs erb.srcnn__END__nHello world! " ; @foo.concat(( 10 + 100 ).to_s); @foo.concat "n" ; @foo

Source Output (after) @foo.concat "require 'erb'nrequire 'rubygems'nrequire 'mmap'nnclass ERB::Compilern def pre_cmd= x; endnend nnerb = ERB.new(Mmap.new(__FILE__), nil, nil, '@foo')nputs erb.srcnn__END__nHello world! " ; @foo.concat(( 10 + 100 ).to_s); @foo.concat "n" ; @foo

Source Output (before) @foo = ''; @foo.concat "require 'erb'nrequire 'rubygems'nrequire 'mmap'nnclass ERB::Compilern def pre_cmd= x; endnend nnerb = ERB.new(Mmap.new(__FILE__), nil, nil, '@foo')nputs erb.srcnn__END__nHello world! " ; @foo.concat(( 10 + 100 ).to_s); @foo.concat "n" ; @foo

Source Output @foo.concat "require 'erb'nrequire 'rubygems'nrequire 'mmap'nnclass ERB::Compilern def pre_cmd= x; endnend nnerb = ERB.new(Mmap.new(__FILE__), nil, nil, '@foo')nputs erb.srcnn__END__nHello world! " ; @foo.concat(( 10 + 100 ).to_s); @foo.concat "n" ; @foo

Adapting to "concat" class IOAdapter < Struct.new(:io) def concat(string) io.write string end end

require 'erb' require 'mmap' class ERB::Compiler def pre_cmd= x; end end class IOAdapter < Struct.new(:io) def concat(string) io.write string end end @foo = IOAdapter.new($stdout) erb = ERB.new(Mmap.new(__FILE__), nil, nil, '@foo') erb.result(binding) __END__ Hello world! <%= 10 + 100 %>

Performance Results* • Slower compiler • Similar output • Lower memory overhead

*YMMV :-(

rack Ruby webserver interface ACK!

not racc Ryet Another Compiler Compiler

Rack • Interface between app code and servers • By Christian Neukirchen

Unicorn (etc) Rack Rails

Unicorn (etc) Rack Rack Adapter RAILS

SLIDE MISSING

Rack Outside Rails

Handler#call(env)

class MyRack def call env [ 200, {'X-RailsConf' => 'yay'}, "hello world!" ] end end

HTTP/1.1 200 OK Connection: close Date: Thu, 03 Jun 2010 03:57:05 GMT Server: WEBrick/1.3.1 (Ruby/ 1.8.7/2009-06-08) Content-Length: 11 X-Railsconf: yay hello world

body#each(&blk)

block must yield a String

class MyRack def call env [ 200, {'X-RailsConf' => 'yay'}, ['hello ', 'America!'] ] end end

GET / HTTP/1.0 HTTP/1.1 200 OK Connection: close Date: Thu, 03 Jun 2010 04:06:08 GMT Server: WEBrick/1.3.1 (Ruby/ 1.8.7/2009-06-08) Content-Length: 14 X-Railsconf: yay hello America!

body#close

class MyRack def call env [ 200, {'X-RailsConf' => 'yay'}, File.open(__FILE__, 'rb') ] end end

HTTP/1.1 200 OK Connection: close Date: Thu, 03 Jun 2010 04:08:21 GMT Server: WEBrick/1.3.1 (Ruby/1.8.7/2009-06-08) Content-Length: 215 X-Railsconf: yay class MyRack def call env [ 200, {'X-RailsConf' => 'yay'}, File.open(__FILE__, 'rb') ] end end

Great Flexibility

Twisting Rack

ERB Handler

class ERBHandler def initialize @root = File.join(File.dirname(__FILE__), 'htdocs') end def call env erb = ERB.new(File.read("#{@root}#{env['REQUEST_PATH']}")) [ 200, {'X-RailsConf' => 'yay'}, erb.result(binding) ] end end

<%= env['SERVER_SOFTWARE'] %> <% def fib n n < 2 ? n : fib(n - 1) + fib(n - 2) end %> <% 1.upto(30) do |i| %> <%= fib(i) %> <% end %>

Connection Times (ms) min mean[+/-sd] median max Connect: 0 0 0.0 0 0 Processing: 3239 3312 91.8 3274 3483 Waiting: 3238 3311 91.2 3274 3482 Total: 3239 3312 91.8 3274 3483

Requests per second: 0.30 [#/sec] (mean) Time per request: 3312.112 [ms] (mean)

Template Caching

class ERBHandler def initialize @root = File.join(File.dirname(__FILE__), 'htdocs') @cache = Hash.new do |h,file| h[file] = ERB.new(File.read("#{@root}#{file}")) end end def call env [ 200, {'X-RailsConf' => 'yay'}, @cache[env['REQUEST_PATH']].result(binding) ] end end

Requests per second: 0.31 [#/sec] (mean) Time per request: 3266.990 [ms] (mean)

Leverage "each"

rd, wr = IO.pipe

ERB Hacks class ERB::Compiler def pre_cmd= x; end end class IO alias :concat :write end

class ERBHandler def initialize @root = File.join(File.dirname(__FILE__), 'htdocs') @cache = Hash.new do |h,file| h[file] = ERB.new( File.read("#{@root}#{file}"), nil, nil, 'wr') end end def call env rd, wr = IO.pipe Thread.new do @cache[env['REQUEST_PATH']].result(binding) wr.close end [ 200, {'X-RailsConf' => 'yay'}, rd ] end end

Rails Improvements

YAML Psych and Syck

Syck • Ruby 1.8 and 1.9 • YAML 1.0 (mostly) parser / emitter • Written by Why

Psych • Ruby >= 1.9.2 only • Wraps libyaml • YAML 1.1 parser / emitter • Written by me

database.yml development: &defaults adapter: sqlite3 database: db/development.sqlite3 test: <<: *defaults database: db/test.sqlite3

i18n ja: calendars: gregorian: days: format: abbreviated: fri: mon: sat: sun: thu: tue: wed:

ﬁxtures default: user: default text: hello world created_at: <%= Time.now.to_formatted_s(:db) %>

Serialized Attributes # Serialize a preferences attribute class User < AR::Base serialize :preferences # ZOMG YAML! end

YAML Outside Rails

Parsing YAML

Ruby 1.8 / 1.9 require 'yaml' YAML.load_ﬁle('some_ﬁle.yml') YAML.load('--- hello world!')

Ruby 1.9.2 / Psych require 'psych' Psych.load_ﬁle('some_ﬁle.yml') Psych.load('--- hello world!')

1.9.2 Opt-in require 'yaml' YAML::ENGINE.yamler = 'psych' YAML.load('--- this is psych')

Dumping YAML

require 'psych' Psych.dump { :foo => 'bar' } { :hello => 'world' }.to_yaml

Dumping JSON?

YAML Map --- foo: bar

YAML Map --- 'foo': 'bar'

YAML Map --- { 'foo': 'bar' }

require 'psych' Psych.to_json { :foo => 'bar' }

Twisting Psych

Custom Emitter

class Foo def initialize @greeting = 'world' end def encode_with(coder) coder['hello'] = @greeting end def init_with(coder) @greeting = coder['hello'] end end

Psych.dump --- !ruby/object:Foo hello: world

Psych.load #<Foo:0x000001009f6770 @greeting="world">

Format Agnostic class Foo def initialize @greeting = 'world' end def encode_with(coder) coder['hello'] = @greeting end def init_with(coder) @greeting = coder['hello'] end end

YAML & JSON Psych.dump Foo.new Psych.to_json Foo.new

class XMLDumper < Psych::Handler def self.dump(object) dumper = new viz = Psych::Visitors::YAMLTree.new({}, dumper) viz << object dumper.doc.to_xml end attr_reader :doc def initialize @doc = Nokogiri::XML::Document.new @doc.root = @doc.create_element 'root' @tags = [] @stack = [@doc.root] end def start_mapping(anchor, tag, implicit, style) tag = @doc.create_element('table') @stack.last << tag @stack << tag end def end_mapping @stack.pop end def scalar(value, anchor, tag, *args) @stack.last << @doc.create_element('tr').tap do |tag| tag << @doc.create_element('td', value) end end end

YAML & JSON & XML Psych.dump Foo.new Psych.to_json Foo.new XMLDumper.dump Foo.new

class HTMLDumper < XMLDumper def initialize @doc = Nokogiri::HTML::Document.new @doc.root = @doc.create_element('html') @doc.root << @doc.create_element('body') @tags = [] @stack = [@doc.root.children.ﬁrst] end end

YAML & JSON & XML & HTML Psych.dump Foo.new Psych.to_json Foo.new XMLDumper.dump Foo.new HTMLDumper.dump Foo.new

module Marshalable module ClassMethods def _load data x = allocate x.init_with Marshal.load data x end end def self.included klass klass.extend ClassMethods end def _dump o coder = {} encode_with coder Marshal.dump coder end end class Foo; include Marshalable; end

YAML & JSON & XML & HTML & Marshal Psych.dump Foo.new Psych.to_json Foo.new XMLDumper.dump Foo.new HTMLDumper.dump Foo.new Marshal.dump Foo.new

5 formats in 2 methods!

Rails is made up of interesting things

Investigate those things

Improve those things

But most of all,

HAVE FUN!

THE END!

Bonus Round!

Twitter Stream

It's JSON! 512 {"in_reply_to_screen_name":null,...} 419 {"in_reply_to_screen_name":"tenderlove"...}

Still JSON! --- {"in_reply_to_screen_name":null,...} ... --- {"in_reply_to_screen_name":"tenderlove"...} ...

Event Output stream = Psych::JSON::Stream.new $stdout loop do stream << { :hello => "world" } end

--- {'hello': 'world'} ... --- {'hello': 'world'} ... --- {'hello': 'world'} ... --- {'hello': 'world'} ...

Psych + Rack

class StreamAPI def call(env) reader, writer = IO.pipe Thread.new(writer) do |wr| stream = Psych::JSON::Stream.new writer loop { stream << { :hello => "world" } } end [200, {}, reader] end end

Ruby on Rails: Tasty Burgers

by Aaron Patterson on Jun 14, 2010

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