How to grab json file from external url(PLACES API) using firebase functions

问题

So, I want to send a request from my app to Firebase using cloud funtions and then process process url and send back JSON file from places api

WHAT I HAVE ALREADY DONE/HAVE=> After Setting up the project in console and getting firebase CLI created a cloud function as follows

After following your comments this is my full function code:

const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();
const rp = require('request-promise');

exports.fetch = functions.https.onCall((req, res) => {

    const url = req.url + '&key=MY_API_KEY';
    var options = {
        uri: url, // Automatically parses the JSON string in the response
        json: true
    };  

    rp(options)
    .then(result => {
        console.log('Get response:' + response.statusCode);
        return res.type('application/json').send(result);
    }).catch(err => {
        // API call failed...
        return res.send({'Error': err});
    });

})

and in java class passed values like this

     private Task<String> addMessage(String url) {
            // Create the arguments to the callable function.
            Map<String, Object> data = new HashMap<>();
            data.put("url", url);///PASSING VALUES HERE
            return mFunctions
                    .getHttpsCallable("fetch")
                    .call(data)
                    .continueWith(task -> 
(String) Objects.requireNonNull(task.getResult()).getData());
        }

Now What my problem is while deploying new function code with firebase CLI I am getting 16:8 error Each then() should return a value or throw promise/always-return as error

Can anyone guide me please..,

URL will be like this : https://maps.googleapis.com/maps/api/place/nearbysearch/json?location=17.4369681,78.4473887&radius=5000&type=airport&sensor=true&key=MY_KEY

Here are the log details from console

2019-07-05T10:06:35.025308453Z D fetch: Function execution started
2019-07-05T10:06:35.265840608Z D fetch: Function execution took 241 ms, finished with status code: 200
2019-07-05T10:06:45.162Z I fetch: Get response:undefined
2019-07-05T10:06:46.062Z E fetch: Unhandled rejection
2019-07-05T10:06:46.062Z E fetch: TypeError: res.send is not a function
    at rp.then.catch.err (/srv/index.js:22:14)
    at bound (domain.js:301:14)
    at runBound (domain.js:314:12)
    at tryCatcher (/srv/node_modules/bluebird/js/release/util.js:16:23)
    at Promise._settlePromiseFromHandler (/srv/node_modules/bluebird/js/release/promise.js:517:31)
    at Promise._settlePromise (/srv/node_modules/bluebird/js/release/promise.js:574:18)
    at Promise._settlePromise0 (/srv/node_modules/bluebird/js/release/promise.js:619:10)
    at Promise._settlePromises (/srv/node_modules/bluebird/js/release/promise.js:695:18)
    at _drainQueueStep (/srv/node_modules/bluebird/js/release/async.js:138:12)
    at _drainQueue (/srv/node_modules/bluebird/js/release/async.js:131:9)
    at Async._drainQueues (/srv/node_modules/bluebird/js/release/async.js:147:5)
    at Immediate.Async.drainQueues (/srv/node_modules/bluebird/js/release/async.js:17:14)
    at runCallback (timers.js:810:20)
    at tryOnImmediate (timers.js:768:5)
    at processImmediate [as _immediateCallback] (timers.js:745:5)

回答1:

You should use promises, in your Cloud Function, to handle asynchronous tasks (like the call to the URL). By default request does not return promises, so you need to use an interface wrapper for request, like request-promise.

The following adaptations should do the trick:

const rp = require('request-promise');

exports.fetch = functions.https.onCall((req, res) => {

  const url = req.url + '&key=MY_API_KEY';
  console.log(url);

  var options = {
    uri: url,
    json: true // Automatically parses the JSON string in the response
  };

  rp(options)
    .then(response => {
      console.log('Get response: ' + response.statusCode);
      res.send(response);
    })
    .catch(err => {
      // API call failed...
      res.status(500).send('Error': err);
    });

})

回答2:

This worked for me., using return before promise returns the result from promise, and we need to use return when using functions.https.onCall and res.send when using functions.https.onRequest it took me 3 days to get it & no need of adding json=true in request-promise options when your url returns a json, it just made things complicated

const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();
const rp = require('request-promise');

exports.fetch = functions.https.onCall((req, res) => {

    const url = req.url + '&key=MY_API_KEY';
    var options = {
        uri: url, // Automatically parses the JSON string in the response
    };

    return rp(options)
    .then(result => {
        console.log('here is response: ' + result);
        return result;
    }).catch(err => {
        // API call failed...
        return err;
    });

})

来源：https://stackoverflow.com/questions/56867732/how-to-grab-json-file-from-external-urlplaces-api-using-firebase-functions