Afaik, there is no way to access the project in the `onRequestReady()`
because you may change or set the targeted project at this point before
passing the request
to subsequent filters.
One possibility to get around this is to use the filter to route your
request to a custom service implementation where it will be have access
the project as an input parameter of the `executeRequest` method.
You may have a look to the The AtlasPrint plugin
(https://github.com/3liz/qgis-atlasprint) use that use this method for
his custom `getatlasprint` implementation.
Your custom service, may then call the native `getprint` request
directly with the WMS service handler
(https://qgis.org/pyqgis/3.42/server/QgsService.html) and the service
registry (https://qgis.org/pyqgis/3.42/server/QgsServiceRegistry.html)
Imho, you shouldn't rely on the QgsProject::instance() when implementing
plugin filters, which may lead to undefined behaviors in some cases. If
you need to acces the
project, prefer a custom service implementation where you get the
project as an input parameter of the `executeRequest` method.
David Marteau
Le 31/03/2025 à 22:05, Ricardo Filipe Soares Garcia da via
QGIS-Developer a écrit :
Hi all
I am implementing a custom plugin for QGIS Server that uses a
QgsServerFilter subclass.
The purpose of this plugin is to use QGIS Server to respond to
`GetPrint` requests. However, I need to pass some runtime parameters
to my map layout before handing it over to `GetPrint`.
I think the place where I should do these preparatory steps, which
ultimately include loading some layers and setting some layout
variables, is in my `onRequestReady()` method.
The problem: I need to be able to set properties on the relevant
QgsPrintLayout instance, but in order to do that I would need to
retrieve it from the current QgsProject instance, and I can't figure
out how to get a hold of it.
Is it possible to get the current instance of QgsProject in the
context of QGIS server?
At first I tried to do it as I would on a plugin for the desktop:
```
qgis_project = QgsProject.instance()
layout_manager = qgis_project.layoutManager()
my_layout = layout_manager.getLayoutByName("the_name")
# this fails, my_layout is None
```
This approach does not work, as the resulting qgis_project is not the
one I am using in my request.
Then I searched through the properties of `QgsServerInterface`, hoping
to find some sort of `getCurrentProject()` method - but this does not
seem to exist.
I also tried loading the project from disk in my plugin with
```
current_project = QgsProject.instance()
current_project.read(server_iface..configFilePath())
```
This second approach does allow me to load up the project, but any
changes I set at runtime are not propagated to subsequent handlers in
the QGIS Server workflow, meaning that the `GetPrint` handler does not
see my changes to the project.
I don't want to save the changes, just set them at runtime and use
them. This is because other (potentially parallel) requests will also
need to modify the aforementioned layout in order to customize their
printing needs.
Is it at all possible to do what I am trying to do? Or is there maybe
a more proper way?
Thanks in advance
--
___________________________ ___ __
Ricardo Garcia Silva
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