Pass data from cloud task to a firebase cloud function - currently getting an error

Question

My question is this: how do I call a Firebase Cloud Function from a Cloud task and pass a payload through?

I tried following the tutorial here. The only difference is that I'm using Cloud functions for Firebase instead of regular Cloud Functions.

Here is my cloud function.

    const functions = require("firebase-functions");
    
    exports.myFunction = functions.https.onRequest((req, res) => {
      console.log(req.query);
      res.send('success');
    });

When I query the url in the browser with parameters ?myparams=data I can log 'data' so I know the cloud function is basically working.

But when I try to call it from my queue (below) I get:

  SyntaxError: Unexpected token o in JSON at position 1
    at JSON.parse (<anonymous>) 

My guess is that req is undefined.

I've been looking at this SO question and I am wondering if it has something to do with needing to use bodyParser for onRequest functions.

HTTP Event Cloud Function: request body value is undefined

I'm also seeing that some people have CORS issues with their cloud functions, which seems like it might be related.

Here is the task queue code that should be sending the payload.

        const seconds = 5;
        const project = 'xxxxx-xxxxxxx';
        const queue = 'xxxxx';
        const location = 'us-west2';
        const url = 'https://us-central1-xxxxx-xxxxx.cloudfunctions.net/writeDB';
        const payload = 'My data';
        const parent = client.queuePath(project, location, queue);
    
        const task = {
          httpRequest: {
            httpMethod: "POST",
            url: url,
            body: Buffer.from(JSON.stringify(payload)).toString("base64"),
            headers: {
              "Content-Type": "application/json"
            },
            oidcToken: {
              serviceAccountEmail
            }
          }
        };
          
        task.scheduleTime = {
          seconds: seconds + Date.now() / 1000,
        };
  
        const request = {parent: parent, task: task};

        await client.createTask(request)
        .then(response => {
          const task = response[0].name;
          console.log(`Created task ${task}`);

          return {'Response': String(response)}
        
      })
      .catch(err => {
          console.error(`Error in createTask: ${err.message || err}`);
          next()
      });

It calls the function, but for some reason it results in the error and the payload isn't logged.

Can anyone help?

As always, I'm happy to clarify the question if anything is unclear. Thanks!

Answer 1

I was able to replicate your error and I managed to fix it by changing the content type headers from "application/json" to "text/plain". I have also removed the JSON.stringify() function in the body value because your payload variable is a String type. Below is my modified sample of your code:

const {CloudTasksClient} = require('@google-cloud/tasks');

// Instantiates a client.
const client = new CloudTasksClient();

const seconds = 5;
const serviceAccountEmail = "xxxx-xxxxx-xxxxxx@appspot.gserviceaccount.com";
const project = 'xxxx-xxxxxx';
const queue = "xx-xxxxx";
const location = 'us-central1';
const url = "https://us-central1-xxxxx-xxxxx.cloudfunctions.net/myFunction";

const payload = 'My Data';

const parent = client.queuePath(project, location, queue);

async function quickstart() {

    const task = {
        httpRequest: {
        httpMethod: "POST",
        url: url,
        body: Buffer.from(payload).toString("base64"), // your previous code: body: Buffer.from(JSON.stringify(payload)).toString("base64"),
        headers: {
            "Content-Type": "text/plain"
        },
        oidcToken: {
            serviceAccountEmail
        }
        }
    };
        
    task.scheduleTime = {
        seconds: seconds + Date.now() / 1000,
    };

    const request = {parent: parent, task: task};

    await client.createTask(request)
    .then(response => {
        const task = response[0].name;
        console.log(`Created task ${task}`);
        return {'Response': String(response)}

    })
    .catch(err => {
        console.error(`Error in createTask: ${err.message || err}`);
        next()
    });

}
quickstart();

In Cloud Functions, I changed req.query to req.body to get the result from Cloud Tasks

const functions = require("firebase-functions");

exports.myFunction = functions.https.onRequest((req, res) => {
    console.log(req.body);
    console.log('success')
    res.send('success');
  });