I'm trying to get documents from Firestore where the location of a restaurant is within a certain radius of the user's location. I am using the geoflutterfire package https://pub.dev/packages/geoflutterfire. How can I display the query results as a snapshot rather than as a stream on my page?
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Is there any way to retrieve a collection along with its sub-collections from Firebase Firestore using Flutter?
fetchTestSite() async {
return await FirebaseFirestore.instance
.collection('sites')
.doc('4R3aOMBFTjumYCbETDU8')
.get()
.then((DocumentSnapshot doc) {
print('document: ${doc.data()}');
});
}
This code snippet only returns the main collection without the existing sub-collections
Is there any way to retrieve a collection along with its sub-collections from Firebase Firestore using Flutter?
No, there is no way you can do that. Queries in Firestore are shallow. This means that it can only return documents from the collection that the query is run against.
There is no way to get documents from a top-level collection and sub-collections in a single query. You can only get documents from a single collection.
However, there is a "hack" that can be made. If you want to get the data from the sub-collection that corresponds to a specific document, you can use a collectionGroup to get documents under a certain path. I explained in the following article:
How to query collections in Firestore under a certain path?
How you can do that and what limitations you might have.
If you consider at some point in time try using the Firebase Realtime Database, what you are looking for it's possible, because when you attach a listener on a specific node, you download all the data beneath it.
I'm building an e-commerce app but when I query firestore to retrieve data I get documents length 0. Data Is present in Firestore. I have no idea what is causing this issue.
I have added all the dependencies.
Firestore.instance
.collection('Products')
.getDocuments().then((value) => print(value.documents.length));
Why this query is not giving me a total number of documents inside Products.
When I run this Query I get a Correct number of documents inside Fruits.
Firestore.instance
.collection('Products')
.document('ABHISHAK FRUITS').collection('Fruits').getDocuments().then((value) => print(value.documents.length));
The log message is correct - your first query returned no documents.
Notice that IDs of the documents in the console are in italics. This means that the document is not present. The reason why the console is showing these missing documents is because the document ID has a subcollection nested under it, and it's letting you click through to browse them.
Your second query using the subcollection works fine because the subcollection has documents present in it.
The bottom line here is that subcollections are not really "contained" within their parent documents like a traditional computer filesystem. The parents documents can be created or deleted without affecting the any subcollections nested under them.
So few day ago I moved my apps posts to cloud firestore from realtime database because of the more flexable querying that firestore apparently has. I have been modifying my code to work with firestore as the new database. Now I ran into a problem. How can I retrieve every document within "Posts" collection that has "Likes" collection that contains a specifically named document? I don't know if that makes sense so here's an image showcasing the problem:
I had a working query for firebase realtime database but can't figure out how to do it with firestore. Is it possible or do I have to change the structure of my database? If I do have to change the structure, what would be the most convenient way of getting the same result?
This is currently not possible with collection group queries. You might be tempted to put a filter on the query for FieldPath.documentId() == 'your-doucment-id', but that just isn't supported. FieldPath.documentId() is actually a token that refers to to fully unique document id, which includes the entire path of the document.
The workaround is to store the document ID as a field in the document, and filter on the contents of that field instead. So, if the document had a field called id with the ID of the document, you could query for collectionGroup("Likes").whereEquals('id', 'your-document-id').
In Firestore I am trying to update avatar (photoUrl) on multiple locations when the user changes the avatar.
Data structure: https://i.imgur.com/yOAgXwV.png
Cloud function:
exports.updateAvatars = functions.firestore.document('users/{userID}').onUpdate((change, context) => {
const userID = context.params.userID;
const imageURL = change.after.data().avatar;
console.log(userID);
console.log(imageURL);
});
With this cloud function, I am watching on user update changes. When the user changes avatar I got userID and a photo URL. Now I want to update all "todos" where participant UID is equal to userID.
You could use the array_contains operator for your query. This allows you to search for array values inside your documents.
https://firebase.google.com/docs/firestore/query-data/queries#array_membership
If you found your documents you have to update the URL on all documents and write the updated documents back to the database.
But this causes a lot of unnecessary writes especially if your todos collection gets bigger and you want to archive the todos data.
Simpler solution:
I suspect a to do list does not have more then 10 users if so this is a lot of trouble to save some document reads.
I would recommend you to just load all user documents you need to show the avatar on the to do list.
I'm using Firebase Cloud Firestore and can't figure out how to access documents without knowing the specific path. The database structure is users/{user id}/favourites/{favourite id}. There are no fields in users/{user id} only subcollections. Knowing the user id, i can get the favourites for the user, but I can't get a list of users to get everyone's favourites. Here is the code I am trying (Java admin SDK):
db.collection("users").get().get()
which results in an empty Iterable with no DocumentSnapshots.
How can I get a list of the most popular favourites?
EDIT: I've discovered I can get a list of users with no fields if I add a field. Even if I delete it later, it still appears as a document in the collection.
EDIT2: I've discovered that I can create an empty document, so I'm just doing that for now. As a one-off, I can get a list of all users from firebase auth and look up which ones have a favourites collection and just set those to empty documents.