I'm trying to read the value for exp_date in my flutter app as seen in this picture:
The field/value pair is in a map called Card which is in a sub collection called sources . I can read the value by putting in the DocId for the sources collection(the other docId is the firebase user uid) with the following:
StreamBuilder(stream: Firestore.instance.collection('stripe_customers').document(userId).collection('sources').document('qRvDob75kTzhT3').snapshots(),builder: (context,snapshot){
if(!snapshot.hasData){
return new Text("Loading");
}
var userDocument = snapshot.data;
return new Text(userDocument["card"]['exp_year'].toString());
},),
But obviously this isn't very practical. How do I access the Card map value without knowing the document id?
There are two ways to get the contents of a document:
Know its entire, unique path.
Make query against a known collection to get matching documents.
If you don't know the id required by #1, you will have to try #2. But since you don't seem to have have a way to filter the documents in that collection, you will have to fetch ALL of the documents. This is probably not what you want to do for scalability purposes.
Give some consideration about how you want to find the data in Firestore before you write the documents.
Related
Guys how can i retrieve a specific document from QuerySnapshot.docs?
I once get all documents of a collection.
And after some code, i want to get a document by its ID from that collection.
I want to get that document specifically from this QuerySnapshot since i don't want to be messed with await later in my code.
So if i can get all documents all at once, why would i get every document one by one later with async call which would waste my time?
The thing would look like this:
QuerySnapshot usersSnapshot = await FirebaseFirestore.instance.collection("users").get();
//
//some code
//
DocumentSnapshot userDoc = usersSnapshot.docs.doc("user12345");
I want to get document with id user12345.
Is there any function like this .doc(ID) that i can apply on QuerySnapshot??
No, there is no such method on QuerySnapshot. You have to locate the document you want by iterating the results of the query in the docs property, and check each DocumentSnapshot for the ID you're looking for.
If you want to make that easier for yourself for repeated lookups, you can iterate the docs list, and build a Map of document snapshots keyed by the ID. Query the Map for each document you want.
I'm new to Cloud Firestore but already made some CRUD operations but now I'm really stuck with this thing.
Each document inside the 'tiposFrota' collection has a key 'nome:' with a unique value, no document will have the same value for the 'nome:' key.
The problem is, whenever the user adds another 'Truck' to some other collections I need to increment the value of 'qtde:' by one, and when they remove 'Truck' the program will increment the number by -1, working as a counter.
I managed to create an operation to update a key value, but only when you have the document id, but in this case the id is autogenerated because they may add or remove standard values from the 'tiposFrota' collection.
FirebaseFirestore.instance
.collection('controladores')
.doc('contadores')
.update({'numFrota': FieldValue.increment(1)}),
I'm really stuck with this, if anyone could please help.
Thanks!
Woah, managed to find a solution by myself, this post Get firestore collections based on values in array list in flutter.
Since the 'nome:' value is unique for each document inside the 'tiposFrota' collection I can use the .where statement as a filter for said document, get the snapshot with all the documents (but only getting one, obviously) and use the 'forEach' method to create a function using the '.id' parameter when calling the document.
FirebaseFirestore.instance
.collection('tiposFrota')
.where('nome', isEqualTo: carMake)
.get()
.then((querySnapshot) {
querySnapshot.docs.forEach((element) {
FirebaseFirestore.instance
.collection('tiposFrota')
.doc(element.id)
.update({
'qtde': FieldValue.increment(1)});
});
}),
I'm working on a Flutter app where each user can create projects, and share projects with other users. I've created a 'shares' collection, where each user's ID is a document, and within that document, all project IDs that have been shared with that user are collected like so, with a boolean that represents whether or not the share has been accepted yet:
Next, I created a collection of the projects themselves, like so:
Now, I'd like to query the 'projects' collection and return only the projects that are in a given user's 'shares' list. First off, how can I get each document in the share list's ID? And secondly, is it possible to compare that ID to the contents of a List using a .where() clause?
I've been trying something like this, but to no avail:
Stream<List<Map<String, dynamic>>> getListOfProjectsForUser({#required List<String> shares}) {
var ref = _firestore.collection('projects');
return ref
.where(shares, arrayContains: ref.id)
.snapshots()
.map((QuerySnapshot snapshot) => snapshot.docs.map((DocumentSnapshot doc) => doc.data()).toList());
}
I also tried this:
Stream<List<Map<String, dynamic>>> getListOfProjectsForUser({#required List<String> shares}) {
var ref = _firestore.collection('projects');
return ref
.where(shares, arrayContains: FieldPath.documentId)
.snapshots()
.map((QuerySnapshot snapshot) => snapshot.docs.map((DocumentSnapshot doc) => doc.data()).toList());
}
Is what I'm trying to do even possible? I've been messing with this for two days and my head's exploding. Any help would be greatly appreciated. Thanks in advance.
You'll need two operations.
Read the document for the user, to determine the list of project IDs.
Perform a in query for the project documents matching those IDs. The in operator accepts up to 10 IDs, so if you have more than 10 projects you'll need multiple queries and merge the results in your application code.
var citiesRef = db.collection("projects");
citiesRef.where(FieldPath.documentId, arrayContains: ['project1id', 'project2id']);
Also see:
The FlutterFire documentation for the where(field, whereIn:) operation
The FlutterFire documentation for the FieldPath.documentId field
First off, how can I get each document in the share list's ID?
For this, you're required to actually query the entire collection. You can iterate the results to collect the IDs of each document. There is no easy way to just get a list of IDs directly from web and mobile client code. See: How to get a list of document IDs in a collection Cloud Firestore?
And secondly, is it possible to compare that ID to the contents of a List using a .where() clause?
If you have a list of document ID strings in memory that could be any length, you will need to perform a query filtering projects for "projOwner" for each individual ID. There are no SQL-like joins in Firestore, so you can't simply join the two collections together with a single query.
Here's how you do a single one - you have to call out the name of the field to filter on:
firestore
.collection("projects")
.where("projOwner", isEqualTo: id)
If you have 10 or less share IDs in the list, you can use an "in" query to find matches from projects, and it will not work with any more.
firestore
.collection("projects")
.where("projOwner", whereIn: listOfIds)
So, if you think the list could ever be larger than 10, you should just start by performing individual queries for each share ID.
if 'arrayContains' is not working try 'whereIn'.
var citiesRef = db.collection("projects");
citiesRef.where(FieldPath.documentId, whereIn: ['project1id',
'project2id']);
I am trying to fetch all documents whose sub-collection contain a specific document ID. Is there any way to do this?
For example, if the boxed document under 'enquiries' sub-collection exists, then I need the boxed document ID from 'books' collection. I couldn't figure out how to go backwards to get the parent document ID.
I make the assumption that all the sub-collections have the same name, i.e. enquiries. Then, you could do as follows:
Add a field docId in your enquiries document that contains the document ID.
Execute a Collection Group query in order to get all the documents with the desired docId value (Firestore.instance.collectionGroup("enquiries").where("docId", isEqualTo: "ykXB...").getDocuments()).
Then, you loop over the results of the query and for each DocumentReference you call twice the parent() methods (first time you will get the CollectionReference and second time you will get the DocumentReference of the parent document).
You just have to use the id property and you are done.
Try the following:
Firestore.instance.collection("books").where("author", isEqualTo: "Arumugam").getDocuments().then((value) {
value.documents.forEach((result) {
var id = result.documentID;
Firestore.instance.collection("books").document(id).collection("enquiries").getDocuments().then((querySnapshot) {
querySnapshot.documents.forEach((result) {
print(result.data);
});
First you need to retrieve the id under the books collection, to be able to do that you have to do a query for example where("author", isEqualTo: "Arumugam"). After retrieving the id you can then do a query to retrieve the documents inside the collection enquiries
For example, if the boxed document under 'enquiries' sub-collection exists, then I need the boxed document ID from 'books' collection.
There is no way you can do that in a single go.
I couldn't figure out how to go backwards to get the parent document ID.
There is no going back in Firestore as you probably were thinking. In Firebase Realtime Database we have a method named getParent(), which does exactly what you want but in Firestore we don't.
Queries in Firestore are shallow, meaning that it only get items from the collection that the query is run against. Firestore doesn't support queries across different collections in one go. A single query may only use the properties of documents in a single collection. So the solution to solving your problem is to perform two get() calls. The first one would be to check that document for existence in the enquiries subcollection, and if it exists, simply create another get() call to get the document from the books collection.
Renaud Tarnec's answer is great for fetching the IDs of the relevant books.
If you need to fetch more than the ID, there is a trick you could use in some scenarios. I imagine your goal is to show some sort of an index of all books associated with a particular enquiry ID. If the data you'd like to show in that index is not too long (can be serialized in less than 1500 bytes) and if it is not changing frequently, you could try to use the document ID as the placeholder for that data.
For example, let's say you wanted to display a list of book titles and authors corresponding to some enquiryId. You could create the book ID in the collection with something like so:
// Assuming admin SDK
const bookId = nanoid();
const author = 'Brandon Sanderson';
const title = 'Mistborn: The Final Empire';
// If title + author are not unique, you could add the bookId to the array
const uniquePayloadKey = Buffer.from(JSON.stringify([author, title])).toString('base64url');
booksColRef.doc(uniquePayloadKey).set({ bookId })
booksColRef.doc(uniquePayloadKey).collection('enquiries').doc(enquiryId).set({ enquiryId })
Then, after running the collection group query per Renaud Tarnec's answer, you could extract that serialized information with a regexp on the path, and deserialize. E.g.:
// Assuming Web 9 SDK
const books = query(collectionGroup(db, 'enquiries'), where('enquiryId', '==', enquiryId));
return getDocs(books).then(snapshot => {
const data = []
snapshot.forEach(doc => {
const payload = doc.ref.path.match(/books\/(.*)\/enquiries/)[1];
const [author, title] = JSON.parse(atob(details));
data.push({ author, title })
});
return data;
});
The "store payload in ID" trick can be used only to present some basic information for your child-driven search results. If your book document has a lot of information you'd like to display once the user clicks on one of the books returned by the enquiry, you may want to store this in separate documents whose IDs are the real bookIds. The bookId field added under the unique payload key allows such lookups when necessary.
You can reuse the same data structure for returning book results from different starting points, not just enquiries, without duplicating this structure. If you stored many authors per book, for example, you could add an authors sub-collection to search by. As long as the information you want to display in the resulting index page is the same and can be serialized within the 1500-byte limit, you should be good.
The (quite substantial) downside of this approach is that it is not possible to rename document IDs in Firestore. If some of the details in the payload change (e.g. an admin fixes a book titles), you will need to create all the sub-collections under it and delete the old data. This can be quite costly - at least 1 read, 1 write, and 1 delete for every document in every sub-collection. So keep in mind it may not be pragmatic for fast changing data.
The 1500-byte limit for key names is documented in Usage and Limits.
If you are concerned about potential hotspots this can generate per Best Practices for Cloud Firestore, I imagine that adding the bookId as a prefix to the uniquePayloadKey (with a delimiter that allows you to throw it away) would do the trick - but I am not certain.
When a new activity is posted i add a new post document into the collection.
Inside this document i have a map where users add confirmation to the event marking it as true and adding his own id.
var snap = await Firestore.instance
.collection('user_posts')
.where("confirmations.${user.id}",isEqualTo: true)
.getDocuments();
With this snippet i'm able to get all the posts confirmed by the user. The issue here is to get this a index is required to perform this query. And this index can't be generic. I can't create a index for each user.
Some idea of how to get it?
Thanks!!
You'll want to turn the confirmations field into an array, and use the (relatively recent) array-contains and arrayUnion operations.
The equivalent query with an array like that would become:
var snap = await Firestore.instance
.collection('user_posts')
.where("confirmations", arrayContains: user.id)
.getDocuments();
And this way you only need an index on confirmations, which is added automatically.
For more on these see:
the blog post introducing these operations
the documentation on updating arrays
the documentation on array membership queries