JSON-RPC API: Difference between revisions

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====HTTP====
====HTTP====
A simple way of manually sending HTTP requests containing a JSON-RPC request to XBMC is using the [http://chrome.google.com/extensions/detail/fhjcajmcbmldlhcimfajhfbgofnpcjmb Simple REST Client] extension for Google's Chrome/Chromium browser. It allows defining an URL and the HTTP request type ('''POST''' is what we need). The actual JSON-RPC request can be defined in the '''Data''' field and then sent to XBMC.
A simple way of manually sending HTTP requests containing a JSON-RPC request to XBMC is using the [http://chrome.google.com/extensions/detail/fhjcajmcbmldlhcimfajhfbgofnpcjmb Simple REST Client] extension for Google's Chrome/Chromium browser. It allows defining an URL and the HTTP request type ('''POST''' is what we need). The actual JSON-RPC request can be defined in the '''Data''' field and then sent to XBMC.
==See also==
*[[/v2|JSON-RPC API v2 (Dharma)]]
*[[/v3|JSON-RPC API v3 (pre Eden)]]


==External links==
==External links==

Revision as of 07:55, 25 October 2011

JSON-RPC is a HTTP- and/or raw TCP socket-based interface for communicating with XBMC. It replaces the soon-to-be-depreceated HTTP API, and offers a more secure and robust mechanism in the same format. It is based upon the JSON-RPC 2.0 specification.

Each method in the interface can have different security needs which means one client may be allowed to only control playback while another can only read and manipulate the library. In version 2 (first stable) and 4 all clients are granted full authority but will later be forced to ask for privileges and the user of XBMC will have to grant said client access. The design of JSON-RPC is that most methods should behave roughly the same and maintain consistency while hiding the mechanics of XBMC from the client creator.

In XBMC JSON-RPC can be accessed over a variety of transports and has been designed from the ground up to be flexible to allow control over new transports easily. Some of the transports have different limitations which will be enforced upon the interaction over that transport. As an example HTTP transports allow response and downloading of files while the raw TCP transport allows response and notifications (events and information XBMC sends to its clients). Depending on the client's needs it will choose one (or many) of the available transports.

Enabling JSON-RPC

Since the interface is available on many transports enabling it depends on the transport.

  • Python: Always enabled
  • HTTP: In System/Settings/Network/Services activate Allow control of XBMC via HTTP
  • TCP: In System/Settings/Network/Services activate Allow programs on this system to control XBMC for localhost access only and Allow programs on other systems to control XBMC for access from other computers as well

Note: The EventServer is a different interface for sending remote keypresses to XBMC, and must be enabled separately, some programs may use both interfaces.

Transports

Functionalities

Response

The Response functionality is the only functionality that should be present in every transport available as it describes the functionality to respond to a JSON-RPC request with a valid JSON-RPC response (be it an error message or an actual response).

Notifications

The Notifications functionality includes both server-side (from the server to clients) and client-side (from clients to the server) notifications. A JSON-RPC notification is a valid JSON-RPC request with no id property. Following the JSON-RPC 2.0 specification any JSON-RPC request with no id must be considered as a notification and the receiver must not send a response upon a notification.

In the specific case of XBMC server-side notifications are used to inform clients about certain events to relieve clients of the need to periodicly poll for certain events. Furthermore there are two ways of client-side notifications. Using JSONRPC.NotifyAll it is possible to ask XBMC to rely the message in the JSON-RPC request to all other connected clients. The second way is to send JSON-RPC requests without an id property in case the client does not care about the response (e.g. the method Player.Stop does not return any useful information to the client).

Direct file download

The Direct file download functionality is the possibility to directly download files from XBMC by calling Files.Download. In this case the term direct means that the download happens within the JSON-RPC response of the Files.Download request.

Redirected file download

The Redirected file download functionality is the possibility to indirectly download files from XBMC by calling Files.PrepareDownload and using the data received in the response to download the file over a different protocol (like HTTP, FTP ...) or another socket. As the Redirected file download is very transport specific it must be handled seperately for every transport supporting it.

Comparison

The following table shows all the available transports and what functionalities they support

Transport Response Notifications Direct file
download
Redirected file
download
Python Yes Yes No No
TCP Yes Yes No No
HTTP Yes No No Yes

API versions

The JSON-RPC API exposed by XBMC is constantly extended to provide better and more functionality to third party applications. For that reason XBMC provides a version information through the JSONRPC.Version method. The rule is that odd version numbers describe an API state, that is not stable and under heavy development whereas even version numbers describe a stable API. Therefore the version number can be used by third party clients to check if their application might not be fully compatible with the JSON-RPC API exposed by a users XBMC installation.

XBMC Release JSON-RPC 2.0 specification Transports
API Version Version Name Method calls Notifications
(server-side)
Notifications
(client-side)
Parameters
by-name
Parameters
by-position
Bulk requests Python TCP HTTP
Version 2 10.0 / 10.1 Dharma Yes Yes No Yes No No Yes Yes Yes
Version 3 / 4 (pre) 11.0 (pre) Eden Yes Yes Yes Yes Yes Yes Yes Yes Yes

Documentation

XBMC's JSON-RPC API has been designed to be self-documentation i.e. a call to JSONRPC.Introspect results in a JSON-RPC response containing a documentation for all the available methods and data types. While this documentation is very incomplete and partly wrong for version 2 it is provided as a full JSON schema starting with version 3. As the documentation retrieved in that way is always specific to the used version of XBMC it is (especially for development versions) the best documentation available and should be prefered over the wiki documentation as the latter always documents the API of the latest development.

Debugging

Output format

To be able to support easier debugging of (third party) development using the JSON-RPC API, the JSON output generated by XBMC can be pretty printed by setting

<jsonrpc>
    <compactoutput>false</compactoutput>
</jsonrpc>

in the advancedsettings.xml. Default JSON output will be in compact format to minimize sent data (especially useful for mobile devices).

Direct interaction

To be able to test some methods of XBMC's JSON-RPC API it can be of great help to be able to send a single hand-written JSON-RPC request to XBMC to see its effect and the generated response. Depending on the transport protocol used there are different possibilities to do that:

TCP

With a telnet connection (using PuTTY on Windows or telnet on Linux) to port 9090 of the machine running XBMC it is possible to send and receive raw json data to/from XBMC.

HTTP

A simple way of manually sending HTTP requests containing a JSON-RPC request to XBMC is using the Simple REST Client extension for Google's Chrome/Chromium browser. It allows defining an URL and the HTTP request type (POST is what we need). The actual JSON-RPC request can be defined in the Data field and then sent to XBMC.

See also

External links