set input or output context dialogflow nodejs v2

Question

I am using dialogflow NPM module and I want to send input/output context but I am not sure how to do. I know I can do in google-assistant NPM with I can set contexts with parameter using below method,

 const parameters = { // Custom parameters to pass with context
     welcome: true,
 };
 conv.contexts.set('welcome-context', 5, parameters);

Answer 1

In order to send a context using the Dialogflow NPM module, you have to first create a context, using dialogflow.ContextsClient and then send it on the query.

To convert the parameters to the format required by Dialogflow you will need to use this module: pb-util

const dialogflow = require('dialogflow');
const { struct } = require('pb-util');  

const projectId = 'projectId';
const contextsClient = new dialogflow.ContextsClient();
const sessionClient = new dialogflow.SessionsClient();

async function createContext(sessionId, contextId, parameters, lifespanCount = 5) {

    const sessionPath = contextsClient.sessionPath(projectId, sessionId);
    const contextPath = contextsClient.contextPath(
        projectId,
        sessionId,
        contextId
    );

    const request = {
        parent: sessionPath,
        context: {
            name: contextPath,
            parameters: struct.encode(parameters)
            lifespanCount
        }
    };

    const [context] = await contextsClient.createContext(request);

    return context;
}


function sendQuery(sessionId, query, context) {

    const session = sessionClient.sessionPath(projectId, sessionId);

    const request = {
        session,
        queryInput: {
            text: {
                text: query
            }
        },
        queryParams: {
            contexts: [context] // You can pass multiple contexts if you wish
        }
    };

    return sessionClient.detectIntent(request);
}

(async() => {
    const parameters = { // Custom parameters to pass with context
       welcome: true
    };

    const sessionId = 'my-session';
    const context = await createContext(sessionId, 'welcome-context', parameters);

    const response = await sendQuery(sessionId, 'Hi', context);

    console.log(response);

})();

Have in mind that you send an input context. The output context is generated in the intent.

If you have trouble authenticating the clients SessionClient & ContextClient you can check this other question: Dialogflow easy way for authorization