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<title>IdHandler Service Contract</title>
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<h2>IdHandler Service Contract</h2>
Besides displaying the names of objects, some pages also want to
provide links to the objects. Unfortunately, there currently is no
way to do so.
<p>
First, we need to know that package_id of the package responsible for
the object, then we would need to figure out the url to that package
instance. This can be done, but even then we would need the local url
to the page being able to display a certain object. Since a package
may have more than one type of objects (i.e. file folders, files, file
versions), we can not simply store additional package information
about which page to call to display an object.
<p>
The solution to this kind of problem is by not resolving the url
at all during display-time, but doing so at the time the user
actually wants to see an object. The links would simply direct
to /o/$object_id, which is a global virtual-url-handling page
that will figure out the package instance url and then relying
upon a Service Contract to get the local url - that means every
package holding displayable objects should implement this
interface for its objects:
<pre>
declare
v_id integer;
begin
v_id := acs_sc_contract.new(
contract_name => 'AcsObject',
contract_desc => 'Acs Object Id Handler'
);
v_id := acs_sc_msg_type.new(
msg_type_name => 'AcsObject.PageUrl.InputType',
msg_type_spec => 'object_id:integer'
);
v_id := acs_sc_msg_type.new(
msg_type_name => 'AcsObject.PageUrl.OutputType',
msg_type_spec => 'page_url:string'
);
v_id := acs_sc_operation.new(
contract_name => 'AcsObject',
operation_name => 'PageUrl',
operation_desc => 'Returns the package specific url to a page
that displays an object',
operation_iscacheable_p => 'f',
operation_nargs => 1,
operation_inputtype => 'AcsObject.PageUrl.InputType',
operation_outputtype => 'AcsObject.PageUrl.OutputType'
);
v_id := acs_sc_impl.new (
'AcsObject',
'apm_package_idhandler',
'acs-kernel'
);
v_id := acs_sc_impl.new_alias (
'AcsObject',
'apm_package_idhandler',
'PageUrl',
'apm_pageurl',
'TCL'
);
acs_sc_binding.new (
contract_name => 'AcsObject',
impl_name => 'apm_package_idhandler'
);
v_id := acs_sc_impl.new (
'AcsObject',
'user_idhandler',
'acs-kernel'
);
v_id := acs_sc_impl.new_alias (
'AcsObject',
'user_idhandler',
'PageUrl',
'acs_user::pageurl',
'TCL'
);
acs_sc_binding.new (
contract_name => 'AcsObject',
impl_name => 'user_idhandler'
);
end;
</pre>
The appropriate tcl-procs look like the following:
<pre>
ad_proc -public apm_pageurl { object_id } {
Service Contract Proc to resolve a URL for a package_id
} {
return
}
namespace eval acs_user {
ad_proc -public pageurl { object_id } {
Service Contract Proc to resolve a URL for a user_id
} {
return "shared/community-member?user_id=$object_id"
}
}
</pre>
Note that the name of the implementation has to be the object-type
followed by _idhandler.
<p>
<hr>
<address><a href="mailto:timo@studio-k4.de">timo@studio-k4.de</a></address>
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