400 Bad Request Error while subscribing users to t

Question

I'm trying to subscribe users to firebase topic on the cloud function. So according to official docs I tried the following code

 request({
        method: 'POST',
        url: "https://iid.googleapis.com/iid/v1:batchAdd",
        json: true,


        headers: {
            'Content-Type':'application/json',
            'Authorization':'key=server key,

        },

        body: JSON.stringify({

          "to": "/topics/name",
          "registration_tokens": ["token value"]

        })
            }, function (error, response, body){
        console.log('error:', error);
        console.log('statusCode:', response && response.statusCode);
        if (response.statusCode >= 400) {
            console.error('HTTP Error: '+response.statusCode+' - '+response.statusMessage);
          }
    });

But it's giving 400 status code instead of 200. Thank you.

Answer 1

You need proper authorization to use Google API. Have you entered it? (on the headers part of your code). Maybe a clue: if you enter the URL indicated on your code in an address bar of a browser you find this:

{"error":"MissingAuthorization"}

As you pointed, error 400 is bad request, i.e., you probably are making some mistake on your requesting action. W3C states:

The request could not be understood by the server due to malformed syntax

Maybe this malformed syntax it's the absence of this authorization, raising this error 400.

Answer 2

I apparently found different documentation than you did for subscribing a device to a topic. This documentation says to use a URL formatted like this:

https://iid.googleapis.com/iid/v1/IID_TOKEN/rel/topics/TOPIC_NAME

A variation on your code that uses this method is below. It works for me. But wouldn't it be much simpler to use admin.messaging().subscribeToTopic()?

 const token = 'f_PWaiHMGvQ:APA91bGN...9F5D5avIpjY57Y098OFsxZLHUZubx0P_';
 const serverKey = 'AAAAyq9marw:APA91b..._Xf-jV472nfn-sb';
 request({
        method: 'POST',
        url: `https://iid.googleapis.com/iid/v1/${token}/rel/topics/myTopic`,
        headers: {
            'Content-Type':'application/json',
            'Content-Length': 0,
            'Authorization':`key=${serverKey}`,
        }
}, function (error, response, body){
    console.log('error:', error);
    console.log('statusCode:', response && response.statusCode);
    if (response.statusCode >= 400) {
        console.error('HTTP Error: '+response.statusCode+' - '+response.statusMessage);
      }
});