External Backends
Right, so you've not got a C or C++ binding for your package system.
You are in the right place.
PackageKit executes scripts written in pretty much any language
(perl,java,python) and watches on the standard out and standard error.
This means we need a standard for what goes on stdin, stdout and stderr to
try and maximise the common code between the backends.
If you are unable to write scripts that conform to these specifications then
just launch a PkSpawn object with stdout and stderr callbacks and then try to
do screenscraping in the backend. This option is least popular.
The following are guidelines. Feel free to break the rules if you have to,
you have a compiled backend to use if you need it.
========= Find Packages =========
FILENAME {backend}-search-name.*
STDIN $options $search_term
options: One of "installed", "available", "all".
search_term: Single word search term with no wildcard chars.
STDERR percentage<tab>$value
value: Percentage complete of the entire transaction
notes: This is optional. Backends should send the DBUS
signal NoPercentageUpdates or use no-percentage-updates
if the remaining position cannot be calculated.
STDERR no-percentage-updates
notes: This is optional and signifies that the helper
is no longer able to send percentage updates.
STDERR error<tab>$enum<tab>description
enum: Enumerated type, e.g. "no-network",
"not-supported" or "internal-error"
description: Long description or error
notes: Errors should only be send on fatal abortion.
STDOUT package<tab>$status<tab>$package_name<tab>$summary
$status: "1" if installed, "0" if not
$package_name: The package name, e.g. openoffice-clipart
$summary: The one line package summary, e.g. "Clipart for OpenOffice"
NOTES: Do not refresh the package cache. This should be fast.
========= Refresh Cache =========
FILENAME {backend}-refresh-cache.*
STDIN <none>
STDERR percentage<tab>$value
value: Percentage complete of the entire transaction
notes: This is optional. Backends should send the signal
NoPercentageUpdates if these are not expected.
STDERR subpercentage<tab>$value
$value: Percentage complete of the sub-transaction.
notes: This is optional.
STDERR error<tab>$enum<tab>description
enum: Enumerated type, e.g. "no-network",
"not-supported" or "internal-error"
description: Long description or error
notes: Errors should only be send on fatal abortion.
STDOUT <none>
========= Install Packages =========
FILENAME {backend}-install.*
STDIN $package
package: Single word package with no wildcard chars.
STDERR percentage<tab>$value
value: Percentage complete of the entire transaction
notes: This is optional. Backends should send the signal
NoPercentageUpdates if these are not expected.
STDERR subpercentage<tab>$value
$value: Percentage complete of the sub-transaction
notes: This is optional.
STDERR status<tab>$state
$state: One of "download", "install", "update", "remove"
notes: This is optional.
STDERR data<tab>$current_data
$current_data: The current worked on package
notes: This is optional, but allows the UI to show what
package is being installed on for that sub-transaction.
STDERR error<tab>$enum<tab>description
enum: Enumerated type, e.g. "no-network",
"not-supported" or "internal-error"
description: Long description or error
notes: Errors should only be send on fatal abortion.
STDOUT package<tab>$status<tab>$package_name<tab>$summary
$status: Always "1"
$package_name: The package name, e.g. openoffice-clipart
$summary: The one line package summary, e.g. "Clipart for OpenOffice"
NOTE: As packages are installed then emit them to the screen.
This allows a summary to be presented after the transaction.
========= Remove Packages =========
FILENAME {backend}-install.*
STDIN $allowdeps $package
allowdeps: Either "yes" or "no". If yes allow other packages
to be removed with the package, but "no" should
cause the script to abort if other packages are
dependant on the package.
package: Single word package with no wildcard chars.
STDERR percentage<tab>$value
value: Percentage complete of the entire transaction
notes: This is optional. Backends should send the signal
NoPercentageUpdates if these are not expected.
STDERR subpercentage<tab>$value
$value: Percentage complete of the sub-transaction
notes: This is optional.
STDERR data<tab>$current_data
$current_data: The current worked on package
notes: This is optional, but allows the UI to show what
package is being installed on for that sub-transaction.
STDERR error<tab>$enum<tab>description
enum: Enumerated type, e.g. "no-network",
"not-supported" or "internal-error"
description: Long description or error
notes: Errors should only be send on fatal abortion.
STDOUT package<tab>$status<tab>$package_name<tab>$summary
$status: Always "1"
$package_name: The package name, e.g. openoffice-clipart
$summary: The one line package summary, e.g. "Clipart for OpenOffice"
NOTE: as packages are installed then emit them to the screen.
This allows a summary to be presented after the transaction.
========= Get Dependancies =========
FILENAME {backend}-get-deps.*
STDIN $package
package: Single word package with no wildcard chars.
STDERR percentage<tab>$value
value: Percentage complete of the entire transaction
notes: This is optional. Backends should send the signal
NoPercentageUpdates if these are not expected.
STDERR error<tab>$enum<tab>description
enum: Enumerated type, e.g. "no-network",
"not-supported" or "internal-error"
description: Long description or error
notes: Errors should only be send on fatal abortion.
STDOUT package<tab>$status<tab>$package_name<tab>$summary
$status: Always "1"
$package_name: The package name, e.g. openoffice-clipart
$summary: The one line package summary.
========= Update System =========
FILENAME {backend}-update-system.*
STDIN <none>
STDERR percentage<tab>$value
value: Percentage complete of the entire transaction
notes: This is optional. Backends should send the signal
NoPercentageUpdates if these are not expected.
STDERR subpercentage<tab>$value
$value: Percentage complete of the sub-transaction
notes: This is optional.
STDERR error<tab>$enum<tab>description
enum: Enumerated type, e.g. "no-network",
"not-supported" or "internal-error"
description: Long description or error
notes: Errors should only be send on fatal abortion.
STDERR requirerestart<tab>$type<tab>$details
type: Enumerated type, e.g. "system", "application", "session"
details: Optional details about the restart
notes: This can be sent as many times as needed by the
backend script. PackageKit will always choose
the 'worst' method in the UI notification.
STDOUT package<tab>$status<tab>$package_name<tab>$summary
$status: Always "1"
$package_name: The package name, e.g. openoffice-clipart
$summary: The one line package summary.
NOTE: As packages are updated then emit them to the screen.
This allows a summary to be presented after the transaction.
========= Get Description =========
FILENAME {backend}-get-description.*
STDIN $package
package: Single word package with no wildcard chars.
STDERR error<tab>$enum<tab>description
enum: Enumerated type, e.g. "no-network",
"not-supported" or "internal-error"
description: Long description or error
notes: Errors should only be send on fatal abortion.
STDOUT description<tab>$package_name<tab>$version<tab>$detail<tab>$url
$package_name: The package name, e.g. openoffice-clipart
$version: The full distro package version
$detail: The multi line package description.
$url: The upstream project homepage
