Couldn't read firebase child - firebase

Question

Users can able to data when they login in. But I want everyone can able to this child.No matter logged in.
Child is "gunluksifreler"
Here are my rules
{
"rules": {
"Homeland": {
".indexOn": ["username","email","bakiyetl","yarismada","yarismadabb","splashmesaj","uygulama1tut","uygulama2tut","uygulama3tut","uygulama4tut","uygulama5tut","uygulama6tut","uygulama7tut","uygulama8tut","uygulama9tut","uygulama10tut"]
},
"Odultalepleri": {
".indexOn": ["username","odul1"]
},
"Yardim": {
".indexOn": ["id"]
},
"gunluksifreler": {
".read": true, // <-- allows every person
".write": true
},
"Devices": {
".read": true, // <-- allows every person
".write": true
},
".read": "auth !== null", // <-- allows read if logged in
".write": "auth !== null" // <-- allows write if logged in
}
}
It can be read for everyone when I set true last read line
".read": true, // <-- allows read everbody
".write": "auth !== null" // <-- allows write if logged in
But this time everyone can read every child. What I'm missing?
Code
var kullanici = firebase.database().ref();
kullanici.on('value' ,function(datasnapshot) {
if(datasnapshot.hasChild("gunluksifreler")){
alert("yes");
}});
But it's not about the code it's about the rules.

Answer 1

If you don't want anonymous users to be able to read the entire database, you should not allow "read": true at the root level in your security rules.
Then if you want to allow everyone to read kullanici, you should allow "read": true on that node in your rules.
So this part of your original rules looks fine to me:
{
"rules": {
"gunluksifreler": {
".read": true
},
".read": "auth !== null"
}
}
I highly recommend focusing the rules/code in your question similarly in the future, as it ensures we're both looking at the same minimal-but-complete fragment.
The problem is not in the rules, but in your code:
var kullanici = firebase.database().ref();
kullanici.on('value', ...
This is trying to read the root of the database, which the rules explicitly disallow. So this read gets rejected.
A good way to remember this is that Firebase security rules don't on their own filter any data. They merely check whether the read you're trying to do is allows. So the read above tries to read the root, which is not allowed. Firebase doesn't check every child node of the root to only return allowed child data, as the performance of that would be hard to guarantee.
If you want read the kullanici node, you should attach your listener to only that node:
var kullanici = firebase.database().ref("kullanici");
kullanici.on('value', ...