Midgard2

Content repository for mobile applications

HenriBergius

Microblogs: @bergiehttp://bergie.iki.fi

Content Repository

Don't invent your own file formats

Content Repository

Objects instead of SQL

Content Repository

Objects instead of SQL

http://xkcd.com/327/

Content Repository

Signals about changes

Content Repository

Data model is scriptable

Content Repository

Synchronization and sharing

With a content repositoryincredible power is at your disposal

Free Content Repositories

• Schema-based, relational

• Query Builder

• C, glib, libgda

• LGPL

• D-Bus signals

• Library

midgard2.org

• Schema-free

• Javascript map/reduce

• Erlang

• Apache License

• JSON polling via HTTP

• Daemon

couchdb.apache.org

...and they talk to each other

The Midgard Project• Object-Relational

Mapping, trees, D-Bus signals

• APIs for C, PHP, Python, Vala, Objective-C, ...

• Linux, Mac, Maemo

• Free software project since 1999

• Contributors from most European countries

• Synchronized release model, every 6 months

Midgard on Maemo 5

Conboy: notes on your phone

Midgard on Maemo 5

Workstreamer: project tracking for N900

Midgard on the web

Qaiku.com: conversational microblogging

Getting started with Midgard

Installation

• Linux distribution repositories (Ubuntu, Debian, RHEL, OpenSuse etc) on OBS: http://download.opensuse.org/repositories/home:/midgardproject:/mjolnir/

• After that Midgard is just an apt-get install python-midgard2 or apt-get install php5-midgard2 away

• Maemo 4 and 5 available in Extras Devel (soonExtras)

• On OS X use MacPortsor the ObjC bundle

Objects are defined by MgdSchema<!-- This will be installed to /usr/share/midgard2/schema/ --><type name="midgard_person"> <property name="id" type="unsigned integer" primaryfield="id"> <description>Local non-replication-safe database identifier</description> </property> <property name="firstname" type="string" index="yes"> <description>First name of the person</description> </property> <property name="lastname" type="string" index="yes"> <description>Last name of the person</description> </property> <property name="birthdate" type="datetime"> <description>Birth date of the person</description> </property> <property name="email" type="string" index="yes"> <description>Email address of the person</description> </property></type>

Midgard API for PHP<?php// Load the Midgard2 API extensiondl('midgard2.so');

// Set up the repository config$config = new midgard_config();$config->dbtype = 'SQLite';$config->database = 'midgardexample';// this will store to SQLite in ~/.midgard2/data/midgardexample.db

// Open a Midgard repository connection$midgard = midgard_connection::get_instance();$midgard->open_config($config);

// Prepare storage for your datamidgard_storage::create_base_storage();midgard_storage::create_class_storage('midgard_person');

Midgard API for PHP// Create a new person object$person = new midgard_person();$person->firstname = 'Leif';$person->lastname = 'Eriksson';$person->create();

// Query system for all persons with lastname "Eriksson"$qb = new midgard_query_builder('midgard_person');$qb->add_constraint('lastname', '=', 'Eriksson');$persons = $qb->execute();foreach ($persons as $person){ echo "{$person->lastname}, {$person->firstname} has GUID {$person->guid}\n"; // Add an email address and update $person->email = 'leif@vinland.no'; $person->update();}

import antigravity

http://xkcd.com/353/

import antigravity# Load the Midgard2 API extensionimport _midgard as midgard

# Set up the repository configconfiguration = midgard.config()configuration.dbtype = 'SQLite'configuration.database = 'midgardexample'# this will store to SQLite in ~/.midgard2/data/midgardexample.db

# Open a Midgard repository connectionconnection = midgard.connection()connection.open_config(configuration)

# Prepare storage for your datamidgard.storage.create_base_storage()midgard.storage.create_class_storage('midgard_person')

Midgard API: PHP vs. Python// Create a new person object$person = new midgard_person();$person->firstname = 'Leif';$person->lastname = 'Eriksson';$person->create();

// Query system for all persons with // lastname "Eriksson"$qb = new midgard_query_builder('midgard_person');$qb->add_constraint('lastname', '=',

'Eriksson');$persons = $qb->execute();foreach ($persons as $person){ echo "{$person->lastname},”

. ” {$person->firstname}”

. “ has GUID {$person->guid}\n"; // Add an email address and update $person->email = 'leif@vinland.no'; $person->update();}

# Create a new person objectperson = midgard.mgdschema.midgard_person()person.firstname = 'Leif'person.lastname = 'Eriksson'person.create()

# Query system for all persons with # lastname "Eriksson"qb = midgard.query_builder('midgard_person')qb.add_constraint('lastname', '=', 'Eriksson')persons = qb.execute()for person in persons: print "%s, %s has GUID %s" \ % (person.lastname, person.firstname, \ person.guid) # Add an email address and update person.email = 'leif@vinland.no' person.update()

Oh, and Vala too!/* valac --debug --pkg midgard2 -o midgard-vala-example example.vala --vapidir=./ */using GLib;using Midgard;namespace MidgardValaExample {

void main() {Midgard.init();

Midgard.Config config = new Midgard.Config();config.read_file ("midgard_test", true);Midgard.Connection cnc = new Midgard.Connection();cnc.open_config (config)

Midgard.Object person = new Midgard.Object (cnc, "midgard_person", null);person.set ("firstname", "Leif");if (person.create()) {

string guid;person.get ("guid", out guid);GLib.print ("Created new person identified by GUID %s \n", guid);

}

any tools you use, Midgard is there

...maybe even in your finger

How about Qt?

• Midgard already works in PySide applications

• Would be great to have proper Qt support

• Anybody want to help with this?

Tree access

• Parent-child relations• get_parent()• list_children()

• Access via named paths• get_by_path()

Extending objects

• Subclasses in MgdSchema<type name="bossa_attendee" extends="midgard_person"> <property name="likesbeer" type="boolean" default="true" /></type>

• Ad-hoc additional propertiesobject.set_parameter('bossa', 'key', 'value')value = object.get_parameter('bossa', 'key')

• Binary attachments are also supported• Metadata in repository, file in filesystem• API provides access to filehandles

Midgard MVC

Put your content repository on the web

Midgard MVC

• Very efficient MVC framework for PHP

• Python and D-Bus for background processing

• Gettext + intl i18n• TAL templating• Full WebDAV support• Git for packaging and

deployment

Midgard MVC

Tomboy web synchronization with Midgard

Midgard Runtime

Explore the possibilities of content repositories

midgard2.org #midgard on FreeNode @MidgardProject