CODEWITHSUNDEEP
javajsonangularfirebasefirebase-realtime-database
Tom Piaggio
Tom Piaggio

Reputation: 669

Iterate a JSON Object of Objects Firebase

I'm using firebase4j (a firebase library for Java, I know it is much better to go with node, I just wanted to try to do it with Java). In my database I need to persist the url of images with a bunch of the picture's information. The thing is that the picture url itself is very deep into the JSON

"users" : {
"aCategory" : {
  "aUser" : {
    "photos" : {
      "photoUid1" : [ {
        "value1" : false,
        "value2" : "qwerty",
        "score" : 40,
        "url" : "http://someurl.com"
      }

That is why I am trying to create an index for the pictures ordered by score, containing the url pointing to the location of the photo object in the firebase database. Here is where the issue begins. Firebase4j does not let you push, to a list for example, so the index ends up with this format:

    {
      "-UID1": {
        "firebaseImgUrl": "users/aCategory/aUser/photos/photoUid1",
        "score": 31
      },
      "-UID2": {
        "firebaseImgUrl": "users/aCategory/aUser/photos/photoUid2",
        "score": 30
      }
    }

I already added the rule ".indexOn" in order for firebase to answer with the right photos when asked for http://firebaseurl.com/users/...?orderBy="score"&limitToFirst=10, which is what I'm doing. I would like to know how should I iterate a JSON object of object as shown in the example above. I'm receiving the data from an Angular 4 client. I've tried a number of methods which haven't worked for me:

result: Photo[] = [];
for(let key in json){
   console.log(key); //prints the UIDs
   console.log(key.url); //url is not a property of string
   //thus
   result.push(new Photo(key.url, key.score)); //not working
}

Upvotes: 0

Views: 708

Answers (1)

fmilani
fmilani

Reputation: 531

The key is only a string, indicating the keys in your json. You should use it to access your object, like this:

result: Photo[] = [];
for(let key in json){
  result.push(new Photo(json[key].firebaseImgUrl, json[key].score));
}

Upvotes: 1

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