Sugar Network/API

This page describes the API that Sugar Network clients use to interact with a Sugar Network server. See also a guide to basic Sugar Network concepts and its twin page for a technical point of view. In addition, visit the introduction page.

Overview
To better understand this API, see a technical explanation of its conceptual level and objects model in particular.

The API operates with Sugar Network resources, which are collections of objects. All objects are identified by globally unique identifiers, GUIDs, and available for operation via basic actions. The API is being provided from a node server or a client. While processing requests, API providers generate events.

The API is RESTful, and is served via HTTP(S) using JSON notation. The common request url format is:

http[s]://SERVER[/RESOURCE[/GUID[/PROPERTY]]][?[cmd=COMMAND][&ARGUMENT=VALUE..]]

When:


 * SERVER, particular Sugar Network API server;
 * RESOURCE, name one of the existing resources;
 * GUID, the RESOURCE's particular object;
 * PROPERTY, particular property of GUID object;
 * COMMAND, optional command name; combination of HTTP request method (GET, POST, PUT, or, DELETE) and [possibly empty] COMMAND composes the requested action;
 * ARGUMENTs and VALUEs depend on the particular action.

In most cases, the server replies in JSON notation. If a request fails, the replied JSON object will contain a request key, with the original request, and error key, with an error message.

API version
Sugar Network nodes might support multiple API versions at once but only one of them is default, i.e., the one which is in use if clients do not specify particular API version. To specify API versions in client request, setup the X-API HTTP header with chosen version. If such header is omitted, default version will be used by the node;

Currently available API versions:


 * 0.1 initial API implementation, should not be used;
 * 0.2 the most recent version, the rest of the document describes exactly this version.

Nodes
These are standard Sugar Network API servers publicly available.


 * node-devel.sugarlabs.org Development server which does not contain important data and is free for any experiments (administrative privileges for anonymous users); default API version is 0.2;


 * node-testing.sugarlabs.org Recent stable release with regular data import from the production server; is still free for any experiments; default API version is 0.1;


 * node.sugarlabs.org Production server;


 * localhost:5001 default url to get access to local proxy provided from user side application; ; default API version is 0.1.

Base API
List of actions common of all API providers.

POST /RESOURCE

Create new resource object.

JSON object keys to send:
 * ''RESOURCE's properties.

JSON object keys to receive:
 * guid, with globally unique identifier that specifies the created object.

PUT /RESOURCE/GUID

Modify resource object. By default, might be called only by GUID creator.

JSON object keys to send:
 * RESOURCE's properties to modify.

DELETE /RESOURCE/GUID

Delete resource object. Actual object destruction won't happen, the object will be hidden. Garbage collection of hidden objects will be processed by Network administrators. By default, this action may be called only by the GUID creator.

GET /RESOURCE[?offset=INTEGER][&limit=INTEGER][&query=STRING][&reply=PROP][&order_by= [+|-] PROP][&group_by=PROP][&PROP=VALUE][&!PROP=VALUE]

Find resource objects.

Where:
 * offset, int start index to return entries from, the default value is 0;
 * limit, int do not return more then specified value, maximal and default values are being setup on server side;
 * query, str search request in Xapian notation; if property is boolean, integer or datetime, it supports searching by ranges, i.e., PROP:[START]..[END];
 * PROP, str supplements query with filtering by exact value of the PROP property; the resulting query string will be ; argument is multiple;
 * !PROP, str supplements query by excluding exact value of the PROP property; the resulting query string will be ; argument is multiple;
 * reply, str RESOURCE properties to return; by default, return only guid property; argument is multiple;
 * order_by, str property to sort the resulting list by; if starts with the -, the order is descending, otherwise it is ascending;
 * group_by, str property name to group resulting list by.

JSON object keys to receive:
 * total, total number in requested query (the reply might contain only the portion restricted by limit request argument);
 * result, an array of dictionaries with resource object properties, dictionaries contain at least guid property.

GET /RESOURCE/GUID[?reply=PROP]

Where:
 * reply, str RESOURCE properties to return; by default, return only guid property; argument is multiple;

Return properties for a particular resource object.

JSON object keys to receive:
 * properties that were specified in reply argument(s), at least guid.

PUT /RESOURCE/GUID/PROP

Modify particular resource property. By default, might be called only by GUID creator.

GET /RESOURCE/GUID/PROP

Return property value for particular resource object.

Data to receive:
 * property value in JSON notation for regular properties;
 * raw data or redirection for BLOB properties.

Aggregated properties
Aggregated properties have special API to treat their content.

POST /RESOURCE/GUID/PROP

Submit new item. The command returns an id for newly created aggregated item. Depending on particular property, new items might be created not only by object's authors.

PUT /RESOURCE/GUID/PROP/ID

Update existing aggregated item. Depending on particular property, the command is allowed either to object's authors or to aggregated item submitter.

DELETE /RESOURCE/GUID/PROP/ID

Delete existing aggregated item. Depending on particular property, the command is allowed either to object's authors or to aggregated item submitter.

Notifications
It is possible to subscribe to server events. Notification will happen using HTML5 Server-sent events (SSE).

To start subscription, send the following request:

GET /?cmd=subscribe

Response will be served with text/event-stream MIME type for default SSE message type. SSE message will be a JSONified object with the following, at least, attributes:


 * event event type.

Node API
This is an API provided by Sugar Network nodes on top of base one.

Authentication
Right now, the only way to be authenticated on a Sugar Network server is by running a local application on the client side and using the API it provides.

TODO

Authorization
Read-only access is available for anonymous requests, except special content like machine serial numbers. But to process any changes, clients need to be authenticated.

Right after creating any Sugar Network object, its author becomes the only user who can process any object modifications afterwards. Authority information will be kept in the author property and can be modified using the following commands.

PUT /RESOURCE/GUID?cmd=useradd&user=USER&role=ROLE

Add another user who can modify the corresponding object. USER argument should be either User guid (for authors registered in the Sugar Network), or, full author name.

PUT /RESOURCE/GUID?cmd=userdel&user=USER

Remove user from the authority list. It is not possible to remove yourself. USER argument should be either User guid (for authors registered in the Sugar Network), or, full author name.

TODO

Retrieving releases
To easy download Context releases and avoid reading raw Context.releases property, there are special high-level API commands.

GET /context/GUID?cmd=solve[&lsb_id=LSB_ID][&lsb_release=LSB_RELEASE][&assume=DEPENDENCY-VERSION]

The command returns information about what particular releases should be downloaded depending on provided requirements. This command might return not only one release, e.g., activities might have dependencies either system packages or another Sugar Network Contexts.

Solving requirements might be:


 * LSB_ID, if Context releases depend on system packages, specify the LSB distributor id to consider while choosing particular packages;
 * LSB_RELEASE, if Context releases depend on system packages, specify the LSB release number of the distribution to consider while choosing particular packages;
 * DEPENDENCY-VERSION, the assume argument instructs server to assume that specified dependency is already available on client side and should be taken into account while solving; this is especially important for package dependencies when server considers packages available only from official repositories but users might have more recent package versions installed in local system; e.g., the above example request will fail without sugar-0.94 because neither lsb_id nor lsb_release were specified (even if LSB information is passed, server might not have information about what package versions come from official repositories).

The resulting info is a JSON object with keys equal to Context guids and value objects for chosen release with the following keys:


 * blob, bundle digest to download;
 * version, chosen version number;
 * title, the Context.title value;
 * command, a command to launch the bundle, only for Sugar activities.

For example, the GET /context/org.laptop.TurtleArtActivity?cmd=solve&assume=sugar-0.94 request returns:

{  "org.laptop.TurtleArtActivity": { "title": "Turtle Blocks", "version": "202", "blob": "http://download.sugarlabs.org/activities/4027/turtleblocks-202.xo", "content-type": "application/vnd.olpc-sugar", "size": 4715955, "unpack_size": 12873871, "command": "sugar-activity TurtleArtActivity.TurtleArtActivity", },  "sugar": { "version": "0.94", }, }

Like the solve command, clone makes a solution but returns bundle itself, so, there is no way to get information about possible dependencies.

GET /context/GUID?cmd=clone[&lsb_id=LSB_ID][&lsb_release=LSB_RELEASE][&assume=DEPENDENCY-VERSION]

Upload releases
To easy upload Context releases and avoid writing to raw Context.releases property, there is a special high-level API command.

POST /context?cmd=submit[&PROP=VALUE][&initial]

Where the PROP arguments are optional release properties. The initial argument asks the system to create new Context resource new release will belong to.

The posting data might be two types,


 * Sugar activities in .xo bundles, there is no need in PROP arguments, all properties will be populated basing on metadata from a .xo bundle; including release notes from the CHANGELOG file in Markdown notation; besides, only in this case initial makes sense because it is the only way to get Context properties;


 * Arbitrary data, all required release properties should be specified in PROP arguments, at least context and version; license should be specified only if there are no existing releases to pickup license from.

Node statistics
The node statistics are about the entire server and depersonalized. Statistics are being collected by analyzing regular requests to an API server and stored for each Sugar Network node. To read such info, call the command:

GET /?cmd=stats[&start=SECONDS][&end=SECONDS][&event=EVENT][&limit=NUMBER]

Where:


 * start and end is a time interval to get statistics for; if omitted, the beginning and the end of entire life cycle will be used;
 * event, multiple argument to specify what stats should be returned; if omitted, return all sources;
 * limit, number of stat records to return for the start-end interval; note that this amount is not precise, the final resultset might be smaller or bigger depending on chosen resolution; stats resolution depends on node configuration, default values are 1 day, 10 days, 30 days, 365 days; if omitted, return end record only.

Possible events are:


 * users, total number of existing User objects;
 * contexts, total number of existing Context objects;
 * released, average number of newly uploaded Context.releases for specified time frame;
 * solved, average number of requested Context solutions for specified time frame; note that this value does not equal to the number of solution usages on client side since solutions might be cached;
 * reported, average number of newly uploaded failure Report objects for specified time frame;
 * topics, total number of top-level Post objects;
 * posts, total number of dependent Post objects.

Client API
The reasons to proxy Sugar Network data on users side:


 * Seamless support offline workflow;
 * One-click launch Sugar activities hosted on Sugar Network.

Proxying happens by providing the same Sugar Network API (with some extra functionality, see below) from local process launched beforehand.

Offline mode
Being connected to a Sugar Network node, local proxy provides original API from the node. If the connection is lost, the proxy will switch to local Sugar Network storage and continue working providing only base API. Any content created in offline mode will be uploaded to the node after getting a connection back.

Besides, local Sugar Network storage will be reused to keep users preferences, such as:


 * Favorited Contexts to select preferred Context resources; these Contexts will be marked by favorite value in the Context.layer property;


 * Checked-in Contexts to keep most recent Context (for activity and book types) version in local storage to make it available in offline; note that there is no need in checking-in to speedup online lunch, versions are being cached anyway; these Contexts will be marked by checkin value in the Context.layer property.

To control users preferences there are special API commands:



PUT /context/GUID?cmd=favorite

Set favorite status.



DELETE /context/GUID?cmd=favorite

Unset favorite status.



PUT /context/GUID?cmd=checkin[&spawn]

Check-in the specified Context. By default, the command will return streamed text/event-stream MIME type data to monitor the progress. If the spawn argument is specified, the command will exit immediately with asynchronous sending progress events.



DELETE /context/GUID?cmd=checkin

Checkout the Context.

Launching
Sugar Network Contexts (for activity and book types) can be launched as-is. The launching process is implicit and includes selecting the most recent (and appropriate for software contexts) version, downloading bundles from the Sugar Network, installing missed software dependencies, execution itself. All downloaded bundles will be cached [with further garbage collecting] to speedup further launching.

Sugar activities will be directly executed. Book Contexts will be opened in the proper application according to its MIME type.

GET /context/GUID?cmd=launch[&args=ARG][&activity_id=ACTIVITY_ID][&object_id=OBJECT_ID][&uri=URI][&app=APP][&spawn]

Arguments that make sense only for Sugar activities:


 * ARG, command line argument to pass to launched activities, repeat ARG for each argument;
 * ACTIVITY_ID, internal activity id which will be auto set if omitted;
 * OBJECT_ID, Journal object id to resume;
 * URI, URL to resume if activity supports this functionality.

Arguments that make sense only for books:


 * APP, specify application Context to open the book by; if omitted, the system will try to find most appropriate option, among all existing software Contexts.

Common arguments:


 * spawn, by default, the command will return streamed text/event-stream MIME type data to monitor the whole launching process until exiting the application; if the spawn argument is specified, the command will exit immediately with asynchronous sending launching events.

Experimental API
There is no guaranty that the following API will be stated as stable or frozen sometime.

Access to Sugar Journal
It is possible to get access to local Sugar Journal using special, journal, resource provided from client API. This kind of access might be useful when local applications cannot use DBus sugar-datastore API, e.g., Javascript applications. API to Journal is restricted only to read-only access:

GET /journal?offset=INTEGER&limit=INTEGER[&query=STRING][&order_by= [+|-] PROP][&QUERY_PROP=VALUE[&...]] GET /journal/JOURNAL_ID[?reply=PROP[,..]] GET /journal/JOURNAL_ID/PROPERTY

Usage
Being HTTP based, Sugar Network API can be used in any manner regular HTTP requests can be handled. But for command-line access, there is a handy tool, sugar-network, which takes care about Sugar Network specific like launching local API (if it is not already available) to get access to local proxy.

The sugar-network command-line format is below. Call sugar-network --help for more detailed info.

sugar-network GET|POST|PUT|DELETE PATH ARG=VALUE [..]


 * PATH, is an url path;
 * , request arguments as they being passed to in url.

POST and PUT commands require data to pass, use the following command-line arguments:


 * -f FILE to specify the file to pass;
 * -d DATA to specify string to pass;
 * -j posted data should be encoded into JSON before posting.