CODEWITHSUNDEEP
firebaseflutterdartgoogle-cloud-firestore
Jo Hassan
Jo Hassan

Reputation: 35

Flutter Firebase Cloud Firestore How to filter a stream with where() query using a subcollection

So i have in my Cloud Firestore I have a collection of recipes that contains documents(with casual ids) with different recipes. Every document has a 2 fields with the recipe name and the recipe duration. Every document has also a collection named likedBy where there is documents that have as ids user ids and have a single field with the date of the like. Now i want to return all recipes that have in their likedBy subCollection the userId. i' ll write what i' ve tried with only essential code.

String userId= 'uiuu4fn3fff4fu';  

Scaffold(
body:StreamBuilder(
stream: THE STREAM THAT I NEED,
builder:(context,snapshot){
return ListView.builder(
itemCount: snapshot.data.documents.length
itemBuilder:(context,index){
return Column(children:[
Text(snapshot.data.documents[index]['recipeName']),
Text(snapshot.data.documents[index][recipeDuration]),]) } ) } ) )

What i want is to return only documents that have in their likedBy subCollection a specific user uid.

I' ve tried with this stream

Firestore.instance.collection('recipes').parent().collection('likedBy').where(FieldPath.documentId, 
isEqualTo,userId).snapshots()

But it doesn' t work and i have no idea what else i can try. Any help is highly apprecieted.

Items should not be added by the users but by admins, that means that there will be a list of items added by admins and a list of users that can add them in favorites and what i want to achieve is that users can see all their favorites in the order in which they saved them. To be clear i want something like Instagram functionality to save posts.

Upvotes: 0

Views: 4053

Answers (2)

Methkal Khalawi
Methkal Khalawi

Reputation: 2477

So you want a way to query subcollection. To do that simply use collectionGroup method:

db.collectionGroup('likedBy').where('userId', '==', '1');

To order by a value use timestamp:

// add to your document
db.collection("items")
 .add({...item, created: firebase.firestore.Timestamp.fromDate(new Date()) })

and to orderby this value use orderby:

db.collection("items")
     .orderBy("created", "asc")

Upvotes: 1

Kris
Kris

Reputation: 3361

What you might want to do instead is have a 'likedBy' property on the recipe document instead of its own sub-collection. If it is just a list of userids that should be no problem. Then you can just say recipeCollection.where(likedBy, array contains: userId)

Upvotes: 0

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