从 node.js 中的 childByAutoId 读取数据

Question

I am trying to read data from firebase that is saved by childByAutoId(). I can successfully read the top half, but the reads what the childByAutoId() is. for example.

and in my firebase functions is

the logger -- uid is BoSwank... is correct, however on the line below for

logger -- workerId is -MBauxL.... is incorrect. That is the value of the childByAutoID() and it should be hkKplzF...

How I am trying to read this data is below.

exports.observeNotifications = functions.database.ref('/notifications/{cardUID}/{workerId}').onCreate((snapshot, context) => {
  var uid = context.params.cardUID;
  var workerId = context.params.workerId;

  console.log('LOGGER --- uid is ' + uid);
  console.log('LOGGER --- workerId is ' + workerId)
})

I thought changing /notifications/{cardUID}/{workerId} to /notifications/{cardUID}/{cardUID/workerId}

and then changing

var workerId = context.params.workerId;

to

var workerId = context.params.cardUID.workerId;

would do the trick but it does not.

Answer 1

With Cloud Functions database triggers, the wildcards in the path only match the names of nodes. They never match the values of any children. What you are seeing right now is the expected behavior, and there's no way to change it.

If you want the value of children under the location that was matched in the path, you're going to have to reach into it using the snapshot parameter that was passed to the function. It is a DataSnapshot object, and contains all of the values of all of the children under the location that was matched in the path.

In your case, the value of workerId is going to be found like this:

const workerId = snapshot.val().workerId

I suggest reading over the documentation for more complete information about how database triggers work.