Journal entry bundles

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Introduction

Entries in the Journal are composed by opaque data stored in one file and metadata properties about that data. For retrieving entries from one XO's Journal to another, all that information about an entry needs to be bundled in a single file. This file is called a 'journal entry bundle'.

Rationale

By bundling journal entries in single files, we can share entries between XO's and retrieve entries from the web (for example downloading from an http server that manages our backups).

Bundle Structure

The journal entry bundle is a directory named after the original entry ID. Each activity bundle must contain a file named "_metadata.json", and following a special format. For example:

15b114ad-1eed-461f-9315-129bba41ce2d/
    _metadata.json
    15b114ad-1eed-461f-9315-129bba41ce2d
    preview/
        15b114ad-1eed-461f-9315-129bba41ce2d

_metadata.json

Metadata is stored in this file as a JSON-encoded dictionary containing each property as a key-value pair:

{"activity_id":"67d38ab406143c6b6b023896e9efa8fc7706ff57",
 "title_set_by_user":"0",
 "uid":"15b114ad-1eed-461f-9315-129bba41ce2d",
 "vid":"1.0",
 "title":"Paint Activity",
 "timestamp":"1192547469",
 "activity":"org.laptop.Oficina",
 "filename":"",
 "icon-color":"#00588C,#00EA11",
 "mtime":"2007-10-16T17:11:09",
 "mountpoint":"18d7246f-72a4-4089-b7dc-2dbdf2b81aa6",
 "keep":"0",
 "mime_type":"image/png",
 "preview":"15b114ad-1eed-461f-9315-129bba41ce2d"}

The preview property is an external property, and as such, its value is the name of a file inside a directory with the property name inside the bundle directory (preview/15b114ad-1eed-461f-9315-129bba41ce2d)

15b114ad-1eed-461f-9315-129bba41ce2d

File named following the ID of the original journal entry. Contains data opaque to the Journal in the format specified by the mime_type metadata property.

preview

Directory containing a single file that in turn contains the data for that property. This is meant for external properties, which can include an amount of data bigger than what can be stored in the _metadata.json file.

Package

Journal entry bundles should be packaged as zip files with the ".xoj" extension. The mime type of the file is 'application/vnd.olpc-journal-entry'.