PHP Content Repository

Porting a Java standard to PHP

Content Repository

Do not re-invent the content storage wheel
Write applications once, switch storage backends

The JCR model

Hierarchical document store

All content is stored in a tree of nodes
Nodes have a name and a type
Nodes have child nodes and properties holding values
Values can be strings or numbers, but also binary file data or references to other nodes

Repository Content

01<jcr:root>
02  <cms>
03    <pages>
04      <home title="Hello">
05        <block title="News"
06          content="Today: PHPCR presentation"/>
07      </home>
08      <contact title="Contact"
09        content="phpcr-users@groups.google.com"/>
10    </pages>
11  </cms>
12</jcr:root>

PHPCR class interaction diagramm Source: phpcr.github.com

Nodes

A Node is a named container located under a parent node
Think of XML elements
Can be created, deleted, modified, copied...
Path is the parent path plus the node name
- Path: /cms/pages/home
- Parent path: /cms/pages
- Node name: home

Properties

A Node has named Properties with values
Think of XML attributes
Data types
- STRING, URI, BOOLEAN, LONG, DOUBLE, DECIMAL, BINARY, DATE, NAME, PATH, WEAKREFERENCE, REFERENCE
(WEAK)REFERENCE: Create links to other nodes
Node and property names can use namespaces to avoid name collisions
- jcr:created, jcr:mimeType, phpcr:class

Primary Node Types

Defines allowed names and types for properties and child nodes
Every node must have a primary node type
Use nt:unstructured to allow anything
Some other built-in types: nt:address, nt:folder, nt:file ...
Define custom types to control your "schema"

Mixin Node Types

No multiple inheritance for primary type.
Mixins bring "traits" to your nodes.
Mixin node types can be assigned to a node during that node's lifetime

JCR / PHPCR Features

Tree access
Access by UUID
Search nodes
Versioning
Capability discovery
XML import and export
Locking
Transactions
Permissions
Node Level Access Control *
Observation

* Not yet implemented in any PHP implementation

From Java to PHP

PHP = Java

Classes and Methods
Interfaces
Namespaces
Access Levels: private / protected / public

PHP != Java

Weak typing
No method return signature
PHP is lazy / Java is overzealous

Simplifications

No Value and ValueFactory but primitive types
Node::getPropertyValue to avoid instantiating even Property
No type specific iterators (but not plain arrays)
Traversable on node, property, query result and so on

Conclusions

Not all data fits well in PHPCR/JCR

For example aggregation is better done in an RDBMS
Store web store product description in PHPCR/JCR
Store web store inventory and orders in RDBMS

Quality

A test suite for PHPCR makes sure all implementations interpret the specification the same way.

Higher quality of implementations
Discover interpretation issues, better compatibility
Implementors need to write less tests of their own

Quality

Test results using Jackalope with the Jackrabbit backend.

......................................S.........S.....II.....   61 / 1222 (  4%)
...........S.S...............................................  122 / 1222 (  9%)
...........SS.......SS.S.......S.............................  183 / 1222 ( 14%)
.............................................................  244 / 1222 ( 19%)
.............................................................  305 / 1222 ( 24%)
.............................................................  366 / 1222 ( 29%)
.............................................................  427 / 1222 ( 34%)
..............................S.........SSS..............I.I.  488 / 1222 ( 39%)
I.I.........................I...................I..I........S  549 / 1222 ( 44%)
I............................................................  610 / 1222 ( 49%)
.....S.......I.....................S..S......................  671 / 1222 ( 54%)
.................SS...............SSSS..S....................  732 / 1222 ( 59%)
.......................................................SSSSS.  793 / 1222 ( 64%)
..........................S.............I......S...........I.  854 / 1222 ( 69%)
.............................SS..................S...........  915 / 1222 ( 74%)
.............................................................  976 / 1222 ( 79%)
............................................................. 1037 / 1222 ( 84%)
...............................S............................. 1098 / 1222 ( 89%)
...........SSSS...........SSS................................ 1159 / 1222 ( 94%)
........................................SSSSSS............... 1220 / 1222 ( 99%)
.

Time: 03:23, Memory: 93.50Mb

OK, but incomplete or skipped tests!
Tests: 1212, Assertions: 6797, Incomplete: 17, Skipped: 49.

Play with it today!

PHPCR Tutorial

See it in action!

Symfony2 CMF sandbox

PHPCR in real live

ServerGrove KnowledgeBase
Used as storage layer in the Symfony Content Management Framework
- Baromètre des prix (Symfony2 CMF for static pages of an otherwise custom web application)
- Liip Company Website
- Joiz for static contents mixed with application generated content
- Used in a Saas CRM service by Quiet Storm Solutions

Many individuals contribute to the effort

0x616469 (Adrian Schlegel)
adou600 (Adrien Nicolet)
beberlei (Benjamin Eberlei)
bergie (Henri Bergius)
bmatzner (Bernd Matzner)
brki (Brian King)
chirimoya (Thomas Schedler)
chregu (Christian Stocker)
cordoval (Luis Cordova)
craigmarvelley (Craig Marvelley)
cryptocompress
damz (Damien Tournoud)
dbojdo (Daniel Bojdo)
dbu (David Buchmann)
dotZoki (Zoran)
ebi (Tobias Ebnöther)
fabian (Fabian Vogler)
flojon (Jonas Flodén)
iambrosi (Ismael Ambrosi)
jakuza (Jacopo Romei)
justinrainbow (Justin Rainbow)
k-fish/kdambekalns (Karsten Dambekalns)
krizon (Kristian Zondervan)
lapistano (Bastian Feder)
lsmith77 (Lukas K. Smith)

mdekrijger
micheleorselli (Michele Orselli)
nacmartin (Nacho Martín)
nicam (Pascal Helfenstein)
Ocramius (Marco Pivetta)
ornicar (Thibault Duplessis)
pajooh (arash)
petesiss (Pete Sisson)
piotras
pitpit (Damien Pitard)
rande (Thomas Rabaix)
richardmiller (Richard Miller)
rndstr (Roland Schilter)
robertlemke (Robert Lemke)
sebastien-roch (Sébastien Roch)
Seldaek (Jordi Boggiano)
simensen (Beau Simensen)
sixty-nine (Daniel Barsotti)
sjopet (Sjoerd Peters)
starkj (Johannes Stark)
stof (Christophe Coevoet)
uwej711 (Uwe Jäger)
vedranzgela (Vedran Zgela)
videlalvaro (Alvaro Videla)
...

Doctrine PHPCR ODM

Object - Document mapper to map plain PHP objects to PHPCR data
Supports the PHPCR concepts like children and references

Thank you

Please give me feedback:

@dbu on Twitter, or david@liip.ch

Github projects

Resources

PHPCR code examples

Creating a session

01use PHPCR\SimpleCredentials;
02 
03// start of implementation specific configuration //
04$parameters = array(
05    'jackalope.jackrabbit_uri'
06        => 'http://localhost:8080/server',
07);
08$factory = new \Jackalope\RepositoryFactoryJackrabbit();
09$repository = $factory->getRepository($parameters);
10// end of implementation specific configuration //
11 
12$creds = new SimpleCredentials('admin','admin');
13$session = $repository->login($creds, 'default');

CRUD operations

01$root = $session->getRootNode();
02 
03// Nodes must be added as child of another node
04$node = $root->addNode('test', 'nt:unstructured');
05 
06// New node is immediately available to this session
07$node = $session->getNode('/test');
08 
09// Create/update a property
10$node->setProperty('prop', 'value');
11 
12// New node is now available for all sessions
13$session->save();
14 
15// Delete the node and all its children
16$node->remove();
17 
18// Fails if a concurrent session also changed '/test'
19$session->save();

Tree Traversal API

01$node = $session->getNode('/site/content');
02 
03foreach ($node->getNodes() as $child) {
04    var_dump($child->getName());
05}
06 
07// or in short
08foreach ($node as $child) {
09    var_dump($child->getName());
10}
11 
12// filter on node names
13foreach ($node->getNodes('di*') as $child) {
14    var_dump($child->getName());
15}

Versioning API

01// make versionable
02$node = $session->getNode('/site/content/about');
03$node->addMixin('mix:versionable');
04$session->save();
05// create initial version
06$node->setProperty('title', 'About');
07$session->save();
08 
09// check-in (create version)
10// and check-out (prepare for further updates)
11// persisted immediately without a save() call
12$vm = $session->getWorkspace()->getVersionManager();
13$vm->checkpoint($node->getPath());

Versioning API

01// update node with some changes
02$node->setProperty('title', 'Ups');
03$session->save();
04 
05// create another version, leave in read only state
06$vm->checkin($node->getPath());
07 
08$base = $vm->getBaseVersion($node->getPath());
09$current = $base->getLinearPredecessor();
10$previous = $current->getLinearPredecessor();
11 
12// get snapshot of old version to look around
13$frozenNode = $previous->getFrozenNode();
14echo $frozenNode->getProperty('title'); // About
15 
16// set the live data back to what is in this version
17$vm->restore(true, $previous);
18 
19$node = $session->getNode('/site/content/about');
20echo $node->getProperty('title'); // About

Search via SQL2 API

01$qm = $workspace->getQueryManager();
02 
03// unlike SQL, in SQL2 "*" does not return all columns
04// but at least the path and match score
05$sql = "SELECT * FROM [nt:unstructured]
06    WHERE [nt:unstructured].type = 'nav'
07    AND ISDESCENDANTNODE('/some/path')
08    ORDER BY score, [nt:unstructured].title";
09$query = $qm->createQuery($sql, 'JCR-SQL2');
10$query->setLimit($limit);
11$query->setOffset($offset);
12$queryResult = $query->execute();
13 
14foreach ($queryResult->getNodes() as $node) {
15    var_dump($node->getPath());
16}

Search via QOM API

01$qm = $workspace->getQueryManager();
02$factory = $qm->getQOMFactory();
03 
04// SELECT * FROM nt:file INNER JOIN nt:folder ON ISCHILDNODE(child, parent)
05$factory->createQuery(
06  $factory->join(
07    $factory->selector('nt:file'),
08    $factory->selector('nt:folder'),
09    Constants::JCR_JOIN_TYPE_INNER,
10    $factory->childNodeJoinCondition(
11        'child', 'parent')),
12  null,
13  array(),
14  array()
15);

Search via Fluent Query API

(With phpcr-utils)

01$qm = $workspace->getQueryManager();
02$factory = $qm->getQOMFactory();
03 
04// SELECT * FROM nt:unstructured
05// WHERE name NOT IS NULL
06// LIMIT 10 OFFSET 10
07$qb = new QueryBuilder($factory);
08$qb->select($factory->selector('nt:unstructured'))
09   ->where($factory->propertyExistence('name'))
10   ->setFirstResult(10)
11   ->setMaxResults(10)
12   ->execute();

Concurrent write operations

01$test = $session->getNode('/test');
02$test1 = $session1->getNode('/test');
03 
04$test->remove();
05$test1->setProperty('prop', 'value');
06 
07$session->save();
08 
09// this will fail as the node is gone
10$session1->save();

Locking

01// prepare
02$test = $session->getNode('/test');
03$test->addMixin('mix:lockable');
04$session->save();
05 
06// use
07$lm = $session->getWorkspace()->getLockManager();
08// lock node and children for 5 seconds
09$lock = $lm->lock('/test', true, true, 5);
10 
11$test1 = $session1->getNode('/test');
12 
13// here you will get an exception that node is locked
14$test1->setProperty('prop', 'value');