PHP Resources compiled by foreign programmers [go]

A list of PHP resources that ziadoz initiated at Github, including: libraries, frameworks, templates, security, code analysis, logs, third-party libraries, configuration tools, Web tools, books, e-books, classic blog posts, and more. Bole Online translated the list of resources as follows:

Dependency management

Dependency and package management library

Composer/Packagist: A package and dependency manager
Composer Installers: A multi-frame Composer library installer
Pickle: A PHP extension installer
Other dependency management
Other related dependency management

Satis: A static Composer repository generator
Composition: A library that checks the Composer environment at runtime
Version: parsing and comparison library for semantic versions
NameSpacer - converts the underline to the library of the namespace
Patch Installer - a library that uses Composer to install patches
Composer Checker - a tool to verify Composer configuration
frame
Web development framework

Symfony2 - a framework of independent components
Zend Framework 2 - Another framework consisting of separate components
Laravel 4 - Another PHP framework
Aura PHP - the framework of the stand-alone component
Yii2- another PHP framework
Nette - another frame made up of individual components
PPI Framework 2 - An Interoperability Framework
Phalcon - a framework implemented through C extensions
Other framework
Other web development frameworks

Symfony CMF - Creating a Content Management Framework for Custom CMS
Knp RAD Bundle-Symfony 2 Rapid Application (RAD) package
Frame assembly
Independent components from the web development framework

Symfony2 Components-Symfony2 components
Zend Framework 2 Components-ZF2 components
Aura Components-PHP5.4 component package
Hoa Project - another PHP component package
Miniature frame
Micro frame and routing

Silex - Microframe based on Symfony2 components
Slim - another simple miniature frame
Bullet PHP - a miniature framework for building REST APIs
Fast Route - Fast Routing Library
Pux - another fast routing library
Other miniature frames
Other related microframes and routing

Silex Skeleton-Silex project architecture
Silex Web Profiler-Silex web debugging toolbar
Stack- Silex/Symfony stackable middleware library
Slim Skeleton-Slim Architecture
Slim View-Slim's custom view collection
Slim Middleware-Slim's custom middleware collection
template
Libraries and tools for templating and lexical analysis

Twig - a comprehensive templating language
Twig Cache Extension - a template fragment cache library for Twig
Mustache - a PHP implementation of the Mustache template language
Phly Mustache - another PHP implementation of the Mustache template language
MtHaml - a PHP implementation of the HAML template language
PHPTAL - a PHP implementation of the TAL template language
Plates - a native PHP template library
Lex - a lightweight template parser
Static site generator
Preprocessing tools to generate the content of a web page

Sculpin - a tool for converting Markdown and Twig to static HTML
Phrozn - another tool for converting Textile, Markdown and Twig to HTML
HTTP
Library for HTTP and site crawling

Guzzle - a comprehensive HTTP client
Buzz - another HTTP client
Requests - a simple HTTP library
HTTPFul - a chained HTTP library
Goutte - a simple web crawler
PHP VCR - library for recording and replaying HTTP requests
URL
Library that parses URLs

Purl - a URL processing library
PHP Domain Parser - a local prefix resolution library
Email
a library for sending and parsing mail

SwiftMailer - a mail solution
PHPMailer - another mail solution
Fetch - an IMAP library
Email Reply Parser - a mail reply parsing library
Stampie-mail service library, not as good as SendGrid, PostMark, MailGun and Mandrill.
CssToInlineStyles - a library that inline CSS in a mail template
file
File processing and MIME type detection library

Gaufrette - a file system abstraction layer
Flysystem - another file system abstraction layer
Canal - a library for detecting internet media types
Apache MIME Types - a library that parses Apache MIME types
Ferret - a MIME detection library
Hoa Mime - another MIME detection library
Lurker - a resource tracking library
PHP File Locator - a library for locating files in large projects
PHP FFmpeg - a library for FFmpeg video packaging.
CSV - a CSV data processing library
Streams stream
Processing stream library

Streamer - an object-oriented stream wrapper library
Dependency Injection dependency injection
Library that implements the dependency injection design pattern

Pimple - a small dependency injection container
Auryn - another dependency injection container
Orno Di - another scalable dependency injection container
PHP DI - a dependency injection using annotations
Acclimate - a generic interface for dependency injection containers and service positioning
Imagery image
Library for processing images

Imagine - an image processing library
PHP Image Workshop - another image processing library
Intervention Image - Another Image Processing Library
GIF Frame Extractor - a library for extracting GIF animation frame information
GIF Creator - a library for creating GIF animations from multiple images
Image With Text - a library that embeds text in an image
Color Extractor - a library that extracts colors from images
Testing
Test code and library for generating test data

PHPUnit - a unit testing framework
DBUnit-PHPUnit database test library
ParaTest-PHPUnit parallel test library
PHPSpec - unit test library based on function point design
Codeception - a full stack test framework
AspectMock- PHPUnit/ Codeception simulation framework.
Atoum - a simple test library
Mockery - a library of simulated objects for testing
Phake - another simulated object library for testing
Prophecy - a highly selectable simulation framework
Faker - a pseudo data generation library
Samsui - another pseudo data generation library
Alice - an expressive generation library
Behat - a behavior-driven development (BDD) testing framework
Pho - a behavior-driven development test framework
Mink-Web acceptance test
HTTP Mock - a library that simulates HTTP requests in unit tests
VFS Stream - a wrapper for testing virtual file system streams
VFS - another for testing virtual file systems
Locust - a modern load test library written in Python
Continuous Integration Continuous Integration
Continuously integrated libraries and applications

Travis CI - a continuous integration platform
PHPCI - a PHP open source continuous integration platform
Sismo - a continuous test service library
Jenkins a PHP-supported continuous integration platform
JoliCi - a continuous integration client written in PHP supported by Docker
Documentation documentation
a library that generates project documents

Sami - an API document generator
APIGen - another API document generator
PHP Documentor 2-An API Document Generator
 

phpDox - a document generator for PHP projects (not limited to API documentation)
Security
Generate secure random numbers, encrypt data, and scan vulnerabilities

HTML Purifier - a standard-compliant HTML filter
RandomLib - a library that generates random numbers and strings
True Random - use www.random.org to generate a library of random numbers
SecurityMultiTool - a PHP security library
PHPSecLib - a pure PHP secure communication library
TCrypto - a simple key-value encryption repository
PHP IDS - a structured PHP security layer
PHP SSH - a pilot object-oriented SSH wrapper library
IniScan - a library for scanning PHP INI files safely
SensioLabs Security Check - a web tool that provides security advice for checking Composer dependencies
Zed - an integrated web application penetration testing tool
Passwords password
Libraries and tools for handling and storing passwords

Password Compat - a compatible library of new PHP5.5 cryptographic functions
Phpass - a portable password hash frame
PHP Password Lib - a library for generating and verifying passwords
Password Policy - a PHP and JavaScript password policy library
Password Validator - checksum upgrade password hash library
Zxcvbn PHP - A realistic PHP password strength estimation library based on Zxcvbn JS
Code Analysis code analysis
Tools for analyzing, parsing, and processing libraries of code libraries

PHP Parser - a PHP parser written in PHP
PHPPHP - a PHP implementation of the PHP virtual machine
PHPSandbox - a PHP sandbox environment
Dissect - a collection of tools for lexical and parsing
PHP Mess Detector - A library for scanning code defects, sub-optimal code, unused parameters, and more.
PHP Code Sniffer - a library that detects conflicts in PHP, CSS, and JS code standards
PHPCPD - a library for detecting copy and paste code
PHP Analyser - a library for analyzing PHP code to find defects and errors
PHP CS Fixer - a coding standard library
PHP Manipulator - a library for analyzing and modifying PHP source code
PHP Metrics - a static measurement library
PHP Refactoring Browser - a set of command line tools for refactoring PHP code
UBench - a simple micro benchmarking library
Athletic - an annotation-based benchmarking library
Mondrian - Using code analysis tools using graph theory
Scrutinizer - a web tool for reviewing PHP code
PHPLOC - a tool for quickly measuring the size of PHP projects
xHprof - another PHP analysis tool
PHPCheckstyle - A tool that helps to follow specific coding conventions.
Debugging debugging
Debug code libraries and tools

xDebug - a tool for debugging and analyzing PHP
PHP Debug Bar - a debug toolbar
PHP Console - a web debugging console
Barbushin PHP Console - another web debugging console using Google Chrome
PHPDBG - an interactive PHP debugger
Tracy - a simple error detection, write log and time measurement library
Build Tools build tool
Project building and automation tools

Go - a simple PHP build tool
Bob - a simple project automation tool
Phake - a PHP clone library
Box - a tool for building PHAR files
Phing - a PHP project build system inspired by Apache Ant
Task Runners Task Runner
Library that automatically runs tasks

Task - a pure PHP task runner inspired by Grunt and Gulp
Robo - an object-oriented configuration PHP task runner
Bldr - a PHP task runner built on Symfony components
Navigation
a tool for building navigation structures

KnpMenu - a menu library
Cartographer - a site map generation library
Asset Management Resource Management
Tools for managing, compressing, and minimizing web site resources

Assetic - a resource management pipeline library
Pipe - another resource management pipeline library
Munee - a resource optimization library
JShrink - a JavaScript minimization library
Puli - a library that detects the absolute path of a resource
Geolocation location
a library for geocoding addresses and latitude and longitude

GeoCoder - a geocoding library
GeoTools - a geography Tool related library
PHPGeo - a simple geodatabase
GeoJSON - a geographic JSON implementation
Date and Time Date and Time
a library that processes dates and times

Carbon - a simple datetime API extension
ExpressiveDate - another datetime API extension
CalendR - a calendar management library
Event event
Time-driven or non-blocking event loop implementation library

React - an event-driven, non-blocking I/O library
Rx.PHP - a reactive extension library
Ratchet - a web socket library
Hoa WebSocket - another web socket library
Hoa EventSource - an event source library
Evenement - an event distribution library
FuelPHP Event - another event distribution library
Logging log
a library that generates and processes log files

Monolog - a comprehensive logging tool
KLogger - an easy to use PSR-3 compatible log class
E-commerce
Handling payments and building libraries and applications for online e-commerce stores

OmniPay - a framework that mixes multiple gateway payment processing libraries
Payum - a payment abstract library
Sylius - an open source e-commerce solution
Thelia - another open source e-commerce solution
Money - A PHP implementation of Fowler Money Mode
Sebastian Money - another library for processing currency values
Swap - a exchange rate library
PDF
Library and software for processing PDF files

Snappy - a PDF and image generator library
WKHTMLToPDF - a tool for converting HTML to PDF
Database database
Database interaction library using object-relational mapping (ORM) or data mapping technology

Doctrine - a comprehensive DBAL and ORM
Doctrine Extensions - a collection of Doctrine behavior extensions
Propel - a fast ORM, migration library and query architect
Eloquent-Laravel 4 ORM
Baum - an Eloquent nested set implementation
Spot2-A MySQL ORM Mapper
RedBean - a lightweight, low-profile ORM
Pomm - a PostgreSQL object model manager
ProxyManager - a collection of tools for generating proxy objects for data mapping
Migrations migration
Help manage database schemas and migrated libraries

PHPMig - another migration management library
Phinx - another database migration management library
Migrations - a migration management library
Doctrine Migrations - a Doctrine Migration Library
NoSQL
Handling libraries for NoSQL backends

MongoQB - a MongoDB query build library
Monga - a MongoDB abstract library
Predis - a fully functional Redis library
Queue queue
a library that handles events and task queues

Pheanstalk - a Beanstalkd client library
PHP AMQP - a pure PHP AMQP library
Thumper - a RabbitMQ schema library
Bernard - a multi-backend abstract library
Search search
Libraries and software that index and execute queries on data

ElasticSearch PHP-ElasticSearch's official client library
Elastica-ElasticSearch client library
Solarium-Solr client library
SphinxQL query builder-Sphinx search engine query library
Command Line command line
Build a library of command line tools

Boris - a miniature PHP REPL
PsySH - another micro PHP REPL
Pecan - an event-driven and non-blocking kernel
GetOpt - a command line select parser
OptParse - another command line select parser
Commando - another simple command line selection parser
GetOptionKit - another command line select parser
Cron Expression - library for calculating cron run dates
ShellWrap - a simple command line wrapper library
Hoa Console - another command line library
Shunt - a library that runs the command line in parallel on multiple remote machines
Cilex - a miniature framework for building command line tools
Authentication authentication
Library for authentication

Sentry - a hybrid authentication and authorization framework library
Sentry Social - a social network authentication library
Opauth - a multi-channel authentication framework
OAuth2 - an OAuth2 authentication service, resource server and client library
OAuth2 Server - another OAuth2 server implementation
PHP oAuthLib - another OAuth library
TwitterOAuth - a Twitter OAuth library
TwitterSDK - a fully tested Twitter SDK
Hawk - a Hawk HTTP authentication library
HybridAuth - an open source social landing library
Markup tag
Processing tagged libraries

Decoda - a lightweight tag parsing library
PHP Markdown - a Markdown parser
CommonMark PHP - a Markdown parser that fully supports CommonMark spec
Dflydev Markdown - another Markdown parser
Parsedown - another Markdown parser
Ciconia - Another Markdown parser that supports Github Markdown style
Cebe Markdown - a fast and scalable Markdown parser
HTML5 PHP - an HTML5 parsing and serialization library
Strings string
a library that parses and processes strings

ANSI to HTML5-ANSI to HTML5 conversion library
Patchwork UTF-8 - a portable library that handles UTF-8 strings
Hoa String - another UTF-8 string library
Stringy - a multi-byte supported string processing library
Color Jizz - library for processing and converting colors
UUID - a library that generates UUIDs
Slugify - converts strings to slug's library
Urlify - a Django URLify.jsPHP channel
Text - a text processing library
SQL Formatter - a library for formatting SQL statements
UA Parser - a library that parses user agent strings
Numbers number
Library for processing numbers

Numbers PHP - a library for working with numbers
Math - a library for handling large numbers
ByteUnits - libraries that parse, format, and convert byte units in binary and metric systems
PHP Units of Measure - a library of units of measure conversion
PHP Conversion - another unit of measure conversion
LibPhoneNumber for PHP-Google phone number processing PHP implementation library
Filtering and Validation Filtering and Validation
a library for filtering and validating data

Filterus - a simple PHP filter library
Respect Validate - a simple validation library
Valitron - another verification library
Upload- A library for processing file uploads and verifications
DMS Filter - an annotation filter library
MetaYaml - a schema validation library that supports YAML, JSON and XML
ISO-codes - Validation of various ISO and ZIP coded libraries (IBAN, SWIFT/BIC, BBAN, VAT, SSN, UKNIN)
REST and API
Develop libraries and web tools for REST-ful APIs

Apigility - an API builder built using Zend Framework 2
Hateoas - a HOATEOAS REST web service library
HAL - a hypertext application language (HAL) build library
Negotiation - a content negotiation library
Drest - a library that exposes Doctrine entities as REST resource nodes
Restler - a lightweight framework that exposes PHP methods as RESTful web APIs
Caching cache
Cache data library

Alternative PHP Cache (APC) - Open PHP pseudo code cache
Cache - a cache library (Doctrine part)
Stash - another cache library
Data structure and storage
Library for implementing data structures and storage technologies

Ardent - a data structure library
PHP Collections - a simple collection library
Serializer - a library for serializing and deserializing data
PHP Object Storage - an object repository
Fractal - a library that converts complex data structures to JSON output
Totem - a library for managing and wearing data exchange sets
PINQ - a PHP real-time Linq library
JsonMapper - a library that maps embedded JSON structures to PHP classes
Notifications notification
Library that handles notification software

Nod - a notification library (Growl, etc.)
Notificato - a library that handles push notifications
Notification Pusher - a separate library for device push notifications
Notificator - a lightweight notification library
Deployment deployment
Project deployment library

Pomander - a PHP application deployment tool
A quick and simple deployer in the Rocketeer-PHP world
Envoy - a tool for running SSH tasks with PHP
Plum - a deployment library
Internationalization and localization
Internationalization (I18n) and localization (L10n)

Aura.Intl
Third party API
Access to third-party API libraries

Amazon Web Service SDK - PHP AWS SDK Official Library
S3 Stream Wrapper-Amazon S3 Stream Wrapper
Stripe-Stripe official PHP library
Campaign Monitor-Campaign Monitor official PHP library
Digital Ocean-Digital Ocean API Interface Library
Github- Github API Interactive Library
PHP Github API - another Github API interactive library
Twitter OAuth-Twitter OAuth Workflow Interactive Library
Twitter REST- Twitter REST API interactive library
Dropbox SDK- The official PHP Dropbox SDK library.
Dropbox SDK - Dropbox SDK official PHP library
Twilio- The official Twilio PHP REST API.
Twilio-Twilio official PHP REST API
MailgunThe official Mailgun PHP API.
MailgunMailgun official PHP REST API
Extensions extension
Help build PHP extension library

Zephir - a compiled language for developing PHP extensions between PHP and C++
PHP CPP - a C++ library for developing PHP extensions
Miscellaneous Miscellaneous
Useful libraries and tools not in the above categories

Spork - a library for forking
JSON Lint - a JSON lint tool
JSONPCallbackValidator - library to validate JSONP callbacks
Pagerfanta - a paged library
Ruler - A simple stateless production environment rules engine.
LiteCQRS - a CQRS (command query responsibility separation) library
Sslurp - a library that reduces SSL processing
PHP Option An optional type library
Metrics - a simple metrics API library
Sabre VObject - a library that parses VCard and iCalendar objects
Annotations - an annotation library (Doctrine part)
Whoops - a good error handling library
Finite - a simple PHP finite state machine
LadyBug - a dumper library
Procrastinator - a library that runs time-consuming tasks
Compose - a functional combo library
SuperClosure - a library that allows closure serialization
Jumper - a remote service execution library
Underscore - a PHP implementation of the Undersccore JS library
PHP PassBook - an iOS PassBook PHP library
PHP Expression - a PHP expression language
RMT - a library for writing versions and publishing software
Wise - a configuration manager
Opengraph - an open gallery
Essence - a library for extracting web media
EMbera - an Oembed consumer library
Graphviz - a graphics library
Monad PHP a simple Monad library
Flux - a regular expression building library
Patchwork - a library that redefines the user
Galapagos-language conversion evolution
Design Patterns PHP - a design pattern repository implemented in PHP
PHPCR - A Java Content Repository (JCR) PHP implementation
Functional PHP - a functional programming library
ClassPreloader - an optimized autoloading library
Lib Country - a library of national and regional data
Lib Accessor - a library that simplifies access
PHPStack - a TCP/IP stack concept written in PHP
Nmap - a Nmap PHP wrapper
Code Mover - a library of mobile code
Iter - a library that uses generators to provide iterative primitives
Lambda PHP - A Lambda Computation Parser in PHP
Country List - List of all countries with names and ISO 3166-1 codes
PHP-GPIO - Library for GPIO pins for Raspberry PI
Print_o- a visualizer for an object graph
Alias - a category name library
Software software
Create a development environment software

PHP installation
Tools to help install and manage PHP on your computer

HomeBrew - an OSX package manager
HomeBrew PHP - a HomeBrew PHP channel
PHP OSX - a PHP installer under OSX
PHP Brew - a PHP version management and installer
PHP Env - another PHP version manager
PHP Switch - another PHP version manager
PHP Build - another PHP version installer
VirtPHP - a tool for creating and managing standalone PHP environments
Development Environment
Software and tools for creating sandbox development environments

Vagrant - a portable development environment tool
Ansible - a very simple compilation framework
Puppet - a server automation framework and application
PuPHPet - a web tool for building PHP development virtual machines
Protobox - another web tool for building PHP development virtual machines
Phansible - a web tool for building PHP development virtual machines with Ansible
Virtual Machines virtual machine
Related PHP virtual machine

HipHop PHP-Facebook PHP virtual machine, runtime and JIT
HippyVM - another PHP virtual machine
Hack - A HHVM programming language that works seamlessly with PHP
IDE integrated development environment
Support for PHP's integrated development environment

Netbeans - an IDE that supports PHP and HTML5
Eclipse for PHP Developers - a PHP IDE based on the Eclipse platform
PhpStorm - a commercial PHP IDE
Web Applications Web Application
Web-based applications and tools

3V4L an online PHP shell
DBV - a database version control application
PHP Queue - an application that manages backend queues
Composer as a Service - a tool to download the Composer package as a zip file
MailCatcher - a web tool for crawling and viewing mail
Resources
A variety of resources to improve your PHP development skills and knowledge, such as books, websites, articles

PHP website
PHP related useful website

PHP The Right Way - A quick guide to PHP best practices
PHP Best Practices - A PHP Best Practice Guide
PHP Weekly - A PHP Newsweek
PHP Security - A PHP Security Guide
PHP FIG- PHP Framework Interaction Group
PHP UG - a website that helps users locate the nearest PHP User Group (UG)
Seven PHP - a site interviewed by members of the PHP community
Nomad PHP - an online PHP learning resource
PHP Mentoring - Peer-to-Peer PHP Mentor Organization
Other Websites Other Websites
Useful website related to web development

The Open Web Application Security Project (OWASP) - an open software security community
WebSec IO - a web security community resource
Web Advent - a web developer calendar
Semantic Versioning - a website that parses the semantic version
Atlassian Git Tutorials - A Git Tutorial Series
Hg Init - a Mercurial tutorial series
Servers for Hackers - a newsletter about server management
PHP books
Very good books related to PHP

Scaling PHP Applications - A Steve Corona eBook for Extending PHP Applications
The Grumpy Programmer’s Guide to Building Testable PHP Applications - A book by Chris Hartjes on building PHP application tests
Grumpy PHPUnit - a book by Chris Hartjes on unit testing with PHPUnit
Mastering Object-Orientated PHP- A Brandon Savage book on PHP object-oriented
Signaling PHP - A book by Cal Evans about capturing PCNTL signals in CLI scripts
Securing PHP: Core Concepts - a book by Chris Cornutt on common security terms and practices for PHP
Modernising Legacy Applications in PHP - A book by Paul M. Jones on the modernization of legacy PHP applications
Other books
Books related to general computing and web development

The Linux Command Line-William Shotts a book on the Linux command line
Understanding Computation-Tom Stuart's book on computational theory
The Tangled Web — Securing Web Applications - Michal Zalewski's book on web application security
Elasticsearch: The Definitive Guide - A guide to working with Elasticsearch by Clinton Cormley and Zachary Tong
Eloquent JavaScript-Marijin Haverbeke a book about JavaScript programming
Vagrant Cookbook-Erika Heidi's book on creating a Vagrant environment
Pro Git-Scott Chacon and Ben Straub on a book about Git
PHP video
Very good video related to PHP

Taking PHP Seriously - from Facebook Keith Adams about PHP advantages
PHP Town Hall - A random PHP podcast of Ben Edmunds and Phil Sturgeon
Programming with AnthonyAnthony Ferrara's Video Series
PHP reading
PHP related reading materials

Create Your Own PHP Framework - A series of articles by Fabien Potencier on how to create your own PHP framework
Seven Ways to Screw Up BCrypt - An article on correcting BCrypt implementation
Preventing CSRF Attacks - an article on organizing CSRF attacks
Don’t Worry About BREACH- An article about BREACH attacks and CSRF tokens
On PHP 5.3, Lamda Functions and Closures - an article about lambda functions and closures
Use Env- An article about using the Unix environment help
Composer Primer- Composer Elementary
Composer Versioning - an article about the Composer version
Composer Stability Flags - an article about the Composer Stability Flag
Innocent Villagefolk or a Pillagin’ Pirate? - An article about PHP getting ideas from other languages
Predicting Random Numbers in PHP - an article about generating random numbers
A 20 Point List for Preventing XSS in PHP - an article about organizing XSS
PHP Sucks! But I Like It! - An article about the pros and cons of PHP
PHP Is Much Better Than You Think - an article about the PHP language and ecosystem
PHP Internals Reading PHP kernel reading
Read the PHP kernel or performance related information

PHP RFCs - PHP RFCs Homepage (Request for Comments)
PHP Internals Book - an online book on the PHP kernel written by three core developers
Print vs Echo, Which One is Faster? - An article about printing and echo performance
The PHP Ternary Operator. Fast or Not? - An article about ternary operational performance
Disproving the Single Quotes Myth - An article about single and double quoted string performance
You’re Being Lied To- An article about the kernel ZVALs
How Long is a Piece of String - An article on the principle of strings
Understanding OpCodes - an article about pseudocode
How Foreach Works-StackOverflow Details about foreach answers
When Does Foreach Copy? - An article about the principle of foreach
How Big Are PHP Arrays (And Values) Really?- An article on the principles of arrays
Why Objects (Usually) Use Less Memory Than Arrays - an article on the principles of objects and arrays
PHP Evaluation Order - an article about PHP evaluation order
Developer's PHP source code: 1 2 3 4-Series on PHP source code
Garbage Collection: 1 2 3 Series on PHP Garbage Collection Principles