Crash while retrieving data from Firebase [closed] - swift

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My Code
let ref = Database.database().reference().child("PostInfo")
let query = ref.queryOrdered(byChild: "post_title").queryEqual(toValue: self.retrieve_title)
query.observeSingleEvent(of: .value) { (snapshot) in
print((snapshot.childSnapshot(forPath: "status").value as? String)!)
}
}
jSon Data
{"PostInfo":{
"-KyjkkEAZeHLjdRLg20w" : {
"postImage" : "https://firebasestorage.googleapis.com/v0/b/hobbyquest-ee18d.appspot.com/o/8C40BA04-6D8D-4A23-B8BB-E1B3AC64E66F.png?alt=media&token=3f0f10e3-a64b-4187-9259-3c25bfc4a9e5",
"post_title" : "hahahahah",
"status" : "a banana an",
"threadForHobby" : "Bowling",
"userID" : "ccuvHt6feYVIO6GUXKo3OpO6VUn2"}
}
I am trying to get the status data from firebase but the app keeps crashing. Please help!

Answer 1

The problem is this line
(snapshot.childSnapshot(forPath: "status").value as? String)!
Your code is reading the data by .value.
.value returns ALL nodes within the given node and you will need to iterate over them. For example. Suppose our database looks like the following and you are querying for posts with a post_title of title_0
PostInfo
post_0
postImage = "www.thing.com"
status = "status_0"
post_title = "title_0"
post_1
postImage = "www.yipee.com"
status = "status_1"
post_title = "title_1"
post_2
postImage = "www.dude.com"
status = "status_2"
post_title = "title_0"
When running your query, both post_0 and post_2 will be returned because they both have title_0
You would need to iterate over the snapshot to get the results.
let ref = self.ref.child("PostInfo")
let query = ref.queryOrdered(byChild: "post_title").queryEqual(toValue: "title_0")
query.observeSingleEvent(of: .value) { (snapshot) in
for child in snapshot.children {
let snap = child as! DataSnapshot
let x = (snap.childSnapshot(forPath: "status").value as? String)!
print(x)
}
}
If you notice - your line of code works in this scenario because it's examining each child as a separate snapshot.
On the other hand, if you only want to return the first match, you can use .childAdded, which will return just an individual node:
let ref = self.ref.child("PostInfo")
let query = ref.queryOrdered(byChild: "post_title").queryEqual(toValue: "title_0")
query.observeSingleEvent(of: .childAdded) { (snapshot) in
let x = (snapshot.childSnapshot(forPath: "status").value as? String)!
print(x)
}

Answer 2

I don't know why but you could do it a different way but changing the layout of your data.
The data would be like this:
{"PostInfo":{
"searchidentifier" : { //whatever identifier you want, I think you're trying to use the post title
"object" : {
"postImage" : "https://firebasestorage.googleapis.com/v0/b/hobbyquest-ee18d.appspot.com/o/8C40BA04-6D8D-4A23-B8BB-E1B3AC64E66F.png?alt=media&token=3f0f10e3-a64b-4187-9259-3c25bfc4a9e5",
"post_title" : "hahahahah",
"status" : "a banana an",
"threadForHobby" : "Bowling",
"userID" : "ccuvHt6feYVIO6GUXKo3OpO6VUn2"}
}
}
And you would retrieve your data like this:
let ref = Database.database().reference().child("PostInfo").child("\(self.retrieve_title)")
ref.observe(.value, with: { (snapshot) in
if snapshot.childrenCount > 0 {
for classes in snapshot.children.allObjects as![FIRDataSnapshot] {
let classesObject = classes.value as? [String: AnyObject]
let postImage = classesObject?["postimage"]
//Retrieve all the other objects here as well
}
}
})