XPInstall
Encyclopedia
XPInstall is a technology used by the Mozilla Application Suite
, SeaMonkey
, Mozilla Firefox
, Mozilla Thunderbird
and other XUL
-based applications for installing Mozilla extensions that add functionality to the main application.
A XPI installer module is a ZIP
file that contains an install script or a manifest at the root of the file, and a number of data files.
In Mozilla, Firefox < 0.7, and Thunderbird < 0.5, the package contained a JavaScript
install script (install.js) with some directives for actions to take during an install, including adding files and directories, removing old or obsolete files and directories, executing command line tools, etc. In more recent Firefox and Thunderbird versions, the install script has been replaced by a chrome manifest and a RDF
file (install.rdf).
Since Firefox 1.0, XPIs from sites other than Mozilla Add-ons
are blocked by default. This was an attempt to prevent malicious programs, like computer virus
es, trojans
and spyware
, from being installed by novice users. While it is possible to put a site into the whitelist that limits sites which can install XPIs, malicious sites cannot install extensions in the background (without human intervention). This is because a confirmation dialog needs to be answered for every single installation of an extension.
However, users are still advised to install extensions from trusted sources only.
Mozilla Application Suite
The Mozilla Application Suite is a cross-platform integrated Internet suite. Its development was initiated by Netscape Communications Corporation, before their acquisition by AOL. It is based on the source code of Netscape Communicator...
, SeaMonkey
SeaMonkey
SeaMonkey is a free and open source cross-platform Internet suite. It is the continuation of the former Mozilla Application Suite, based on the same source code...
, Mozilla Firefox
Mozilla Firefox
Mozilla Firefox is a free and open source web browser descended from the Mozilla Application Suite and managed by Mozilla Corporation. , Firefox is the second most widely used browser, with approximately 25% of worldwide usage share of web browsers...
, Mozilla Thunderbird
Mozilla Thunderbird
Mozilla Thunderbird is a free, open source, cross-platform e-mail and news client developed by the Mozilla Foundation. The project strategy is modeled after Mozilla Firefox, a project aimed at creating a web browser...
and other XUL
XUL
In computer programming, XUL , the XML User Interface Language, is an XML user interface markup language developed by the Mozilla project. XUL operates in Mozilla cross-platform applications such as Firefox...
-based applications for installing Mozilla extensions that add functionality to the main application.
A XPI installer module is a ZIP
ZIP (file format)
Zip is a file format used for data compression and archiving. A zip file contains one or more files that have been compressed, to reduce file size, or stored as is...
file that contains an install script or a manifest at the root of the file, and a number of data files.
In Mozilla, Firefox < 0.7, and Thunderbird < 0.5, the package contained a JavaScript
JavaScript
JavaScript is a prototype-based scripting language that is dynamic, weakly typed and has first-class functions. It is a multi-paradigm language, supporting object-oriented, imperative, and functional programming styles....
install script (install.js) with some directives for actions to take during an install, including adding files and directories, removing old or obsolete files and directories, executing command line tools, etc. In more recent Firefox and Thunderbird versions, the install script has been replaced by a chrome manifest and a RDF
Resource Description Framework
The Resource Description Framework is a family of World Wide Web Consortium specifications originally designed as a metadata data model...
file (install.rdf).
Since Firefox 1.0, XPIs from sites other than Mozilla Add-ons
Mozilla Add-ons
Mozilla Add-ons is the official Mozilla Foundation website to act as a repository for add-ons for Mozilla software, including Mozilla Firefox, Mozilla Thunderbird, SeaMonkey, and Mozilla Sunbird. These add-ons include extensions, themes, dictionaries, search bar "search engines," and plugins...
are blocked by default. This was an attempt to prevent malicious programs, like computer virus
Computer virus
A computer virus is a computer program that can replicate itself and spread from one computer to another. The term "virus" is also commonly but erroneously used to refer to other types of malware, including but not limited to adware and spyware programs that do not have the reproductive ability...
es, trojans
Trojan horse (computing)
A Trojan horse, or Trojan, is software that appears to perform a desirable function for the user prior to run or install, but steals information or harms the system. The term is derived from the Trojan Horse story in Greek mythology.-Malware:A destructive program that masquerades as a benign...
and spyware
Spyware
Spyware is a type of malware that can be installed on computers, and which collects small pieces of information about users without their knowledge. The presence of spyware is typically hidden from the user, and can be difficult to detect. Typically, spyware is secretly installed on the user's...
, from being installed by novice users. While it is possible to put a site into the whitelist that limits sites which can install XPIs, malicious sites cannot install extensions in the background (without human intervention). This is because a confirmation dialog needs to be answered for every single installation of an extension.
However, users are still advised to install extensions from trusted sources only.
Web browsers
- Mozilla Application SuiteMozilla Application SuiteThe Mozilla Application Suite is a cross-platform integrated Internet suite. Its development was initiated by Netscape Communications Corporation, before their acquisition by AOL. It is based on the source code of Netscape Communicator...
- Mozilla FirefoxMozilla FirefoxMozilla Firefox is a free and open source web browser descended from the Mozilla Application Suite and managed by Mozilla Corporation. , Firefox is the second most widely used browser, with approximately 25% of worldwide usage share of web browsers...
- FlockFlock (web browser)Flock was a web browser that specialized in providing social networking and Web 2.0 facilities built into its user interface.Earlier versions of Flock used the Gecko HTML rendering engine by Mozilla....
- SeaMonkeySeaMonkeySeaMonkey is a free and open source cross-platform Internet suite. It is the continuation of the former Mozilla Application Suite, based on the same source code...
- Netscape BrowserNetscape BrowserNetscape Browser is the name of a proprietary Windows web browser published by AOL, but developed by Mercurial Communications. It is the eighth major release in name of the Netscape series of browsers, originally produced by the defunct Netscape Communications Corporation.While Netscape Browser's...
Other applications
- NvuNvuNvu is a WYSIWYG HTML editor, based on the Composer component of Mozilla Application Suite and Gecko 1.7. It is a common WYSIWYG editor for Linux, Microsoft Windows and Macintosh, intended to be an open source equivalent to proprietary software like Microsoft Expression Web and Adobe Dreamweaver...
(web authoring application) - SongbirdSongbird (software)Songbird is a free and open source software audio player and web browser, with a stated mission "to incubate Songbird, the first Web player, to catalyze and champion a diverse, open Media Web."...
(media player and organiser) - Mozilla SunbirdMozilla SunbirdMozilla Sunbird is a free and open source, cross-platform calendar application that was developed by the Mozilla Foundation, Sun Microsystems and many volunteers...
- Mozilla ThunderbirdMozilla ThunderbirdMozilla Thunderbird is a free, open source, cross-platform e-mail and news client developed by the Mozilla Foundation. The project strategy is modeled after Mozilla Firefox, a project aimed at creating a web browser...
- Google Gears