[FireStore] How to decode Timestamp in Multiplatform Code (Android/iOS)

[wezley98]

Given

data class Article(
    val title: String = "",
    val subTitle: String = "",
    val image: String = "",
    val date: Double = 0.0,
    val content: String = ""
)

Firebase.firestore.collection("articles")
            .get()
            .documents
            .map { doc ->
                Article(
                    doc.get("title"),
                    doc.get("subTitle"),
                    doc.get("image"),
                    doc.get("date"),
                    doc.get("content")
                )
            }

When

date is type timestamp in Firestore.

Then

How do we decode this type in commonMain for example? I have tried setting Article.date to String and Double and both crash.

 kotlinx.serialization.SerializationException: Expected Timestamp(seconds=1606944088, nanoseconds=0) to be double

Does the SDK provide any method to help with decoding this automatically?

[nbransby]

Yes, have a read of https://github.com/GitLiveApp/firebase-kotlin-sdk#serialization

[wezley98]

@nbransby Thanks for the reply, I had already read the docs, I couldn't find anywhere to pass in the Class serializer for Article as .get() doesn't take any parameters the same way set() would. We are trying to read data from Firestore.

suspend fun get(): QuerySnapshot

[nbransby]

@Serializable
data class Article(
    val title: String = "",
    val subTitle: String = "",
    val image: String = "",
    val date: Double = 0.0,
    val content: String = ""
)

Firebase.firestore.collection("articles")
            .get()
            .documents
            .map { doc -> doc.data(Article.serializer())  }

[nbransby]

Or you might be affected by #64 ?

[wezley98]

@nbransby Thanks for the code, I just tried that exact sample code in Android and still get,

kotlinx.serialization.SerializationException: Expected Timestamp(seconds=1606944088, nanoseconds=0) to be double

[matanmarciano]

@wezley98 any solution?

[RZahr]

What about encoding it ? i.e. adding a date in the where clause Query.where("updatedDate", greaterThan = what_to_place_here)

[manuelh19]

What about encoding it ? i.e. adding a date in the where clause Query.where("updatedDate", greaterThan = what_to_place_here)

Any updates on this?