system
The system
module enables an add-on to get information about the
environment it's running in, access arguments passed to it via the cfx
--static-args
option, and
quit the host application.
Querying Your Environment
Using the system
module you can access environment
variables (such as PATH
), find out which operating system your add-on is
running on and get information about the host application (for example,
Firefox or Fennec), such as its version.
var system = require("sdk/system");
// PATH environment variable
console.log(system.env.PATH);
// operating system
console.log("platform = " + system.platform);
// processor architecture
console.log("architecture = " + system.architecture);
// compiler used to build host application
console.log("compiler = " + system.compiler);
// host application build identifier
console.log("build = " + system.build);
// host application UUID
console.log("id = " + system.id);
// host application name
console.log("name = " + system.name);
// host application version
console.log("version = " + system.version);
// host application vendor
console.log("vendor = " + system.vendor);
// host application profile directory
console.log("profile directory = " + system.pathFor("ProfD"));
Accessing --static-args
Static arguments are accessible by name as properties of the
staticArgs
property.
var system = require("sdk/system");
console.log(system.staticArgs.foo);
Quit the host application
To quit the host application, use the
exit()
function.
var system = require("sdk/system");
system.exit();
API Reference
Functions
exit(code)
Quits the host application with the specified code
.
If code
is omitted, exit()
uses the
success code 0
. To exit with failure use 1
.
var system = require("sdk/system");
system.exit();
To exit with failure, set this to 1
. To exit with success, omit this
argument.
pathFor(id)
Firefox enables you to get the path to certain "special" directories, such as the desktop or the profile directory. This function exposes that functionality to add-on authors.
For the full list of "special" directories and their IDs, see "Getting_files in special directories".
For example:
// get Firefox profile path
var profilePath = require('sdk/system').pathFor('ProfD');
// get OS temp files directory (/tmp)
var temps = require('sdk/system').pathFor('TmpD');
// get OS desktop path for an active user (~/Desktop on linux
// or C:\Documents and Settings\username\Desktop on windows).
var desktopPath = require('sdk/system').pathFor('Desk');
The ID of the special directory.
The path to the directory.
Properties
staticArgs : Object
The JSON object that was passed via the
cfx --static-args
option.
For example, suppose your add-on includes code like this:
var system = require("sdk/system");
console.log(system.staticArgs.foo);
If you pass it a static argument named "foo" using --static-args
, then
the value of "foo" will be written to the console:
(addon-sdk)~/my-addons/system > cfx run --static-args="{ \"foo\": \"Hello\" }" Using binary at '/Applications/Firefox.app/Contents/MacOS/firefox-bin'. Using profile at '/var/folders/me/DVFDGavr5GDFGDtU/-Tmp-/tmpOCTgL3.mozrunner'. info: system: Hello
env : Object
This object provides access to environment variables.
You can get the value of an environment variable by accessing the property with that name:
var system = require("sdk/system");
console.log(system.env.PATH);
You can test whether a variable exists by checking whether a property with that name exists:
var system = require("sdk/system");
if ('PATH' in system.env) {
console.log("PATH is set");
}
You can set a variable by setting the property:
var system = require("sdk/system");
system.env.FOO = "bar";
console.log(system.env.FOO);
You can unset a variable by deleting the property:
var system = require("sdk/system");
delete system.env.FOO;
You can't enumerate environment variables.
platform : String
The type of operating system you're running on. This will be one of the values listed as OS_TARGET, converted to lower case.
var system = require("sdk/system");
console.log("platform = " + system.platform);
architecture : String
The type of processor architecture you're running on.
This will be one of: "arm"``,
"ia32", or
"x64"`.
var system = require("sdk/system");
console.log("architecture = " + system.architecture);
compiler : String
The type of compiler used to build the host application.
For example: "msvc"
, "n32"
, "gcc2"
, "gcc3"
, "sunc"
, "ibmc"
var system = require("sdk/system");
console.log("compiler = " + system.compiler);
build : String
An identifier for the specific build, derived from the build date.
This is useful if you're trying to target individual nightly builds.
See nsIXULAppInfo's appBuildID
.
var system = require("sdk/system");
console.log("build = " + system.build);
id : String
The UUID for the host application. For example,
"{ec8030f7-c20a-464f-9b0e-13a3a9e97384}"
for Firefox.
This has traditionally been in the form
"{AAAAAAAA-BBBB-CCCC-DDDD-EEEEEEEEEEEE}"
but for some applications it may
be in the form "appname@vendor.tld"
.
See nsIXULAppInfo's ID
.
var system = require("sdk/system");
console.log("id = " + system.id);
name : String
The human-readable name for the host application. For example, "Firefox".
var system = require("sdk/system");
console.log("name = " + system.name);
version : String
The version of the host application.
var system = require("sdk/system");
console.log("version = " + system.version);
platformVersion : String
The version of XULRunner that underlies the host application.
See nsIXULAppInfo's platformVersion
.
var system = require("sdk/system");
console.log("XULRunner version = " + system.platformVersion);
vendor : String
The name of the host application's vendor, for example: "Mozilla"
.
var system = require("sdk/system");
console.log("vendor = " + system.vendor);