Extended bundles

From OLPC

Revision as of 21:30, 28 January 2009 by Sj (Talk | contribs)
(diff) ← Older revision | Current revision (diff) | Newer revision → (diff)
Jump to: navigation, search
This page is about a proposed bundle type. For other sorts of bundles, see Bundle (disambiguation).


NOTE: The contents of this page are not set in stone, and are subject to change!

This page is a draft in active flux ...
Please leave suggestions on the talk page.

Extended bundles are a proposed way to share arbitrary collections of files between nodes on a network. These could be zipped directories of files of various mimetypes, or collections or projects or files specific to one activity. This has not been implemented as of XO OS 8.2.0, nor has a bundle activity to create them. The current bundle types supported by Sugar are content bundles and activity bundles.

Extended bundles are collections of objects and files that are bundled together with metadata for easy sharing and discovery, a less specific version of the content and activity bundles which were implemented first. Facilities are needed for creating bundles, sharing them, and opening them and using their contents in other activities.

Contents

Introduction

Every general collection of related material in the Sugar environment can be packaged into a self-contained "bundle". The bundle has a name and icon and may contain resources, including code and other files, needed to show or otherwise use the bundled materials. Resources or executable code not provided by the base system may be packaged within the bundle; the bundle may also indicate resources or activities on which it depends.

See also
OLPC Bitfrost in general and its section on software installation, HIG-Activities and its section on activity bundles and extended bundles.

Extended bundles

this section refers to a proposed bundle type yet to be implemented in Sugar

Everything on a laptop, such as projects for an activity, recorded images or video or audio, or created text and other files, is meant to be sharable between children. Packaging sets of materials or resources together allows for a set of related work to be identified and shared as a group.

If a child doesn't have the activity used to create, edit, or view something, it should be automatically transfered to the child when he or she asks to receive a shared item. Identifying dependencies for extended bundles allows easy sharing and reuse of created work without elaborate comparisons of system components.

Location

Extended bundles are installed, opened, and removed automatically by Sugar, in response to user actions. Sugar places these bundles in a directory of its choice. These bundles should not rely on being installed in a specific location, and should use relative paths where paths are necessary. They should not rely on the bundle's base directory name remaining the same. Sugar may rename the activity bundle base directory at any time to prevent conflicts.

To be implemented

There is an extended bundle activity that is launched when such a bundle is compiled for sharing or received.

include note on current operation when this is implemented
ditto any files created when an extended bundle is received or opened, to indicate it is open and in use for remixing with specific activities

Extended bundles should NEVER store local state or preferences in the extended bundle itself. These should be stored in a directory in the user's sugar profile, available through the SUGAR_PROFILE environment variable.

Bundle Structure

The extended bundle is a directory, with a name ending in ".collection". Each extended bundle must, in a subdirectory called 'collection', contain a file named "collection.info", and following a special format. For example:

monday-photos.collection/
    locale/
        de_DE/
            collection.linfo
        zh_CN/
            collection.linfo
    collection/
        collection.info
        collection-monday-photos.svg
    icons/
collection

All metadata about the extended bundle is organized in this subdirectory.

icons

Contains icons used by the bundle while being opened and used.


info file format

.info files follow a key/value pair format, similar to the fd.o desktop entry spec, but not conforming to it. An example is shown here:

[Collection]
name = monday-photos
collection_version = 1
host_version = 1
service_name = com.redhat.Sugar.CameraActivity
icon = activity-web
class = cameraactivity.CameraActivity
mime_types = application/pdf;image/jpeg

A more detailed explanation of the valid properties follows:

[Collection]
The collection.info file must begin with [Collection], and only that, on the first line of the file
name = monday-photos
This is the name is displayed in Sugar referring to the collection. A 'name' key without a bracketed language code is the "en_US" localized name of the collection. The collection.info file must have this key.
collection_version = 1
Each collection.info file must have a "collection_version" key. The version is a single positive integer. Larger versions are considered "newer". The value assigned to this key should be considered opaque to the collection and the extended bundle activity; the only requirement of the collection is that it must be larger for new collections under the same name.
host_version = 1
Each collection.info file must have a "host_version" key. The version is a single positive integer. This specifies the version of the Sugar environment with which the collection (and its metadata) is compatible... (fixme: need to specify sugar versions somewhere. Obviously we start with 1. see this problem in activity bundles)
service_name = com.redhat.Sugar.CameraActivity ???
This is the collection's dbus service name... required? [TBD]. The name should conform to the D-Bus spec - in particular, hyphens are not allowed (although this wasn't enforced in earlier builds, see Trac 6226). It is used as the collection's default service type when it is shared on the network. To determine this type, the distinct parts (separated by the '.' character) are reversed, any '.' is replaced by a '_' character, and the type is prefixed by a '_' character. So in this example, the default service type would be "_CameraActivity_Sugar_redhat_com".
icon = collection-web
It points to the collection's icon. The icon is looked up in the activity bundle's base directory. It cannot contain a path. When searching for the icon in the activity bundle's base directory, only an file with the icon name and the extension '.svg' will be looked for.
exec = myfactory myoptions
something used for activity bundles that doesn't seem relevant here.
class = browseractivity.BrowserActivity
something used for activity bundles that doesn't seem relevant here.
mime_types = application/pdf;image/jpeg
List of mime types used by the collection, separated by semi colons. It's used when opening a file from the web or to present to the user a list of activities which can open a certain journal object.
show_launcher = yes
This key is optional. If not present, or if present with a value of "yes", the collection is shown with its icon in the default extended-bundle-manager panel launcher, and a valid 'icon' key/value pair is required. If specified with a value of "no", the activity is not shown in the launcher for the extended bundle manager, and the 'icon' key is not required.

Collection name localization

Localized [meta]data lives in a locale directory. Each language stores its localized keys in a separate directory named for the language's ISO code. Localized keys from the 'activity.info' file are stored in the 'activity.linfo' files in that directory. For example, German-localized German (as opposed to Swiss-localized German) language translations are stored in the 'de_DE/activity.linfo' file:

Example.collection/
    examplecollection.py
    collection/
        collection.info
    locale/
        de_DE/
            collection.linfo
        de_CH/
            collection.linfo

At this time, only translations for the 'name' key from the 'collection.info' file is supported. A localized 'de_DE/collection.linfo' file would look like:

[collection]
name = Montag-Fotos

Keys in the languague-specific '.linfo' files selectively override keys from the 'collection.info' file; if a key is not present in the '.linfo' file the value from the 'collection.info' file is used instead.

Package

Extended bundles should be packaged as zip files with the ".xoc" extension.

Other technologies comparison

Extended bundles are similar to zip files or Java JAR files; a simple mechanism to encapsulate everything you need in a single directory that can be moved around independently, though without the notion that everything you need to understand or use elements of the extended bundle is contained within it.

As compared to klik, it's not intended to replicate a local Unix directory structure inside the package; the collection can still link to system provided binaries and such. There's also no server-side component other than compressing the archive and sending it over the network. There is some sort of dependency checking, since extended bundles are not required to be self-contained and often contain materials which derive from and can only be used with specific activities.


Use cases

Example use cases

1. Aliya wants to tag a set of 10 photographs, 2 sound recordings, and 2 text clips "Leaf Walk", and to share them with Barabbas. Barabbas receives a copy of this bundle, opens it, and tags some of the photographs as personal favorites; he also pulls the text clips and photos into an essay, and saves it as a document. He then adds photos of his own to the bundle and shares it with Aliya again (or perhaps it never stopped being shared?).

2. a Bundle Activity -- a tool for creating flat or heirarchical structures out of different objects - perhaps from different places on one machine - and zipping them up into something that can be passed around and shared; so that they can be opened and separated into their subcomponents and stored in different places on another machine.

This article is a stub. You can help the OLPC project by expanding it.
Personal tools
  • Log in
  • Login with OpenID
About OLPC
About the laptop
About the tablet
Projects
OLPC wiki
Toolbox