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Performance: Fetch all widgets models in one comm message
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Through the new control comm target
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maartenbreddels authored and martinRenou committed Dec 21, 2021
1 parent 41ad079 commit 041c686
Showing 1 changed file with 116 additions and 0 deletions.
116 changes: 116 additions & 0 deletions packages/voila/src/manager.ts
Original file line number Diff line number Diff line change
Expand Up @@ -194,7 +194,123 @@ export class WidgetManager extends JupyterLabManager {
});
}

/**
* This is the implementation of building widgets models making use of the
* jupyter.widget.control comm channel
*/
async _build_models(): Promise<{ [key: string]: base.WidgetModel }> {
const models: { [key: string]: base.WidgetModel } = {};
const commId = base.uuid();
const initComm = await this._create_comm(
'jupyter.widget.control',
commId,
{ widgets: null },
{ version: '1.0.0' }
);

// Fetch widget states
let data: any;
let buffers: any;
try {
await new Promise((resolve, reject) => {
initComm.on_msg(msg => {
data = msg['content']['data'];

if (data.method !== 'update_states') {
console.warn(`
Unknown ${data.method} message on the Control channel
`);
return;
}

buffers = (msg.buffers || []).map((b: any) => {
if (b instanceof DataView) {
return b;
} else {
return new DataView(b instanceof ArrayBuffer ? b : b.buffer);
}
});

resolve(null);
});

initComm.on_close(reject);

// Send a states request msg
initComm.send({ method: 'request_states' }, {});
});
} catch (error) {
console.warn(
'Failed to open "jupyter.widget.control" comm channel, fallback to slow fetching of widgets.',
error
);
// Fallback to the old implementation for old ipywidgets versions (<=7.6)
return this._build_models_slow();
}

initComm.close();

const states: any = data.states;

// Extract buffer paths
// Why do we have to do this? Is there another way?
const bufferPaths: any = {};
for (const bufferPath of data.buffer_paths) {
if (!bufferPaths[bufferPath[0]]) {
bufferPaths[bufferPath[0]] = [];
}
bufferPaths[bufferPath[0]].push(bufferPath.slice(1));
}

const widgetPromises: Promise<base.WidgetModel>[] = [];

// Start creating all widgets
for (const [widget_id, state] of Object.entries(states) as any) {
try {
const comm = await this._create_comm('jupyter.widget', widget_id);

// Put binary buffers
if (widget_id in bufferPaths) {
const nBuffers = bufferPaths[widget_id].length;
base.put_buffers(
state,
bufferPaths[widget_id],
buffers.splice(0, nBuffers)
);
}

const modelPromise = this.new_model(
{
model_name: state.model_name,
model_module: state.model_module,
model_module_version: state.model_module_version,
model_id: widget_id,
comm: comm
},
state.state
);
widgetPromises.push(modelPromise);
} catch (error) {
// Failed to create a widget model, we continue creating other models so that
// other widgets can render
console.error(error);
}
}

// Wait for widgets to be created
const widgets = await Promise.all(widgetPromises);
for (const model of widgets) {
models[model.model_id] = model;
}

return models;
}

/**
* This is the old implementation of building widgets models
* We keep it around for supporting old ipywidgets versions (<=7.6)
*/
async _build_models_slow(): Promise<{ [key: string]: base.WidgetModel }> {
const comm_ids = await this._get_comm_info();
const models: { [key: string]: base.WidgetModel } = {};
/**
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