launchpad-dev team mailing list archive

[Leonard Richardson <leonard.richardson@xxxxxxxxxxxxx>]

> Not surprising, but how can we tell the restfulclient that the url for the 
> entry has changed?

Named operations don't really have hooks for this kind of thing. OTOH if
you set a regular field (possibly through a mutator) and that happens to
change the object's URL, lazr.restful knows to send a redirect to the
new URL.

I would like to get rid of that named operation altogether if possible. 
setTarget() is a method that sets _either_ project _or_ source_package.
Both of these are normal fields of the branch, and if you made them
directly settable the API would be simpler. The only part of
setTarget()'s logic the end-user needs to know is "if the branch is ever
missing both project and source_package, it gets automatically moved
into the junk namespace of the branch owner". That information can go
into the descriptions of project and source_package.

But setTarget sets _either_ project or source_package. lazr.restful
prohibits one field from having two mutators, but you might be able to
declare a single method with different fixed arguments as the mutator
for two different fields. Realistically, though, this has never been
tried before and strains the capabilities of the system.

A more realistic solution might be to implement setattr for 'project'
and 'source_package' in Branch. This would let us treat them like normal
fields without having to do any lazr.restful hacks.

On top of this, I can implement something in lazr.restful that checks
the URL of an object before and after invoking a POST named operation.
But "this named operation needs special treatment" is a code smell. It
indicates that the system is more complex than it needs to be.

In this case, if the user thinks "I want to move this branch to project
foo", they have to look at the apidoc, discover that setting the project
is a special case of setting the "target", and invoke a named operation
called setTarget. Ideally they would be able to set .project=foo and
save.

Summary: I should extend the 'check if the URL has changed' code to run
after a POST named operation, but I don't think we need to publish this
particular named operation, and turning project_link and
sourcepackage_link into read-write fields will also solve your problem.

Leonard