Data model synchronization

Add, rename, or clear data through app.data_model, and the browser follows, because every connection owns a WebApplicationController whose data_model stays synchronized with that browser alone. Data, progress, selection, workflow, and jobs never route through a global "current session".

Initial and session data

Seed data belongs to the server host:

import imfusion
from imfusion_webappkit import ImFusionWebApp


webapp = ImFusionWebApp()
planning_ct = imfusion.load("scan.nii.gz")[0]
webapp.initial_data.add(planning_ct, "Planning CT")
webapp.run()

Each new connection receives serialized copies in an isolated session model, so an in-place change in one browser cannot mutate another session's seed data. Inside actions and workflows, the injected app is the session controller:

def clear_session(app):
    app.data_model.clear()


def process(image, app):
    modify(image)
    app.data_model.update(app.data_model.index(image))
    return image

There is deliberately no runtime ImFusionWebApp.data_model proxy because a server may have several active browser sessions.

Collection operations

The synchronized model supports:

• indexing by integer, list, or slice;
• iteration, len(model), and size;
• add(data, name=\"\") and add(list_of_data);
• remove(data_or_index) and clear();
• get(name), contains(data), and index(data);
• get_name, set_name, update(index), update_metadata(index), and replace(index, data, name=None).

update(index) pushes an in-place modification to the browser. The ordered browser model is rebuilt from the session model so subsequent input references remain aligned with server indices.

update_metadata(index) is the cheap variant for changes that leave the pixels alone. The caller asserts that; the pixels are never compared, because comparing them would cost as much as sending them.

def relabel(image, app):
    image.modality = imfusion.Data.Modality.LABEL
    app.data_model.update_metadata(app.data_model.index(image))

Only the name and the modality currently avoid the full transfer, because they are the only fields the web SDK can write onto a dataset the browser already holds. A change to the spacing or the matrix falls back to the same full transfer as update(index), which update_metadata reports by returning False and logging why. Callers do not need to change when the SDK gains the missing setters; the same call simply gets cheaper.

replace(index, data, name=None) swaps an object while preserving its model position and browser views. Processing steps use it internally when replacing the output of a previous run. When passing a list to add, omit name; one name cannot be applied to a list and raises ValueError.

Relationship to imfusion.DataModel

The common flat collection API intentionally resembles imfusion.app.data_model, but WebAppKit has documented differences:

• add retains the Python object instead of copying it;
• get returns None when a name is absent;
• remove additionally accepts an integer index;
• grouping, root_node, and parent traversal are not implemented;
• update, update_metadata, get_name, and set_name are web synchronization extensions.

Selection

app.selected_data returns the current browser-visible selection. app.select_data(data_or_list) updates it from Python. Named action and workflow inputs remain explicit through InputSpec and are not inferred from arbitrary multi-selection.

Data references are released on the ImFusion SDK owner thread when the browser disconnects.