I am running a firestore query to get data but the query is returning data from cached data queries earlier and then returns additional data (which was not queried earlier) in the second pass from server. Is there a way I can disable caching for firestore queries so that request goes to DB every time I query something.
this.parts$ = this.db.collection<OrderBom>('OrderBom', ref => {
let query : firebase.firestore.Query = ref;
query = query.where('orderPartLC', '==', this.searchValue.toLowerCase());
return query;
}).valueChanges();
Change that .valueChanges() to a .snapshotChanges() then you can apply a filter. See the example below.
I dont like changing default behavior (default configurations). I saw it's a desired behavior and the good practice is to show the data as soon as possible to the user, even if you refresh twice the screen.
I dont think is a bad practice to filter on fromCache === false when we dont have a choise. (In my case I do more requests after i receive this first one so due to promises and other async 'tasks' cache/server order is completly lost )
See this closed issue
getChats(user : User) {
return this.afs.collection<Chat>("chats",
ref => ref.where('participantsId', 'array-contains', user.id)
.snapshotChanges()
.pipe(filter(c=> c.payload.doc.metadata.fromCache === false)).
.pipe(map(//probaly want to parse your object here))
}
if using AngularFire2 you can try:
I read on the Internet that you can disable offline persistence - which caches your results -by not calling enablePersistence() on AngularFireStoreModule.
I have done the first and still had no success, but try it first. What I managed to do to get rid of caching results was to use the get() method from class DocumentReference. This method receives as parameter a GetOptions, which you can force the data to come from server. Usage example:
// fireStore is a instance of AngularFireStore injected by AngularFire2
let collection = fireStore.collection<any>("my-collection-name");
let options:GetOptions = {source:"server"}
collection.ref.get(options).then(results=>{
// results contains an array property called docs with collection's documents.
});
Persistence and caching should be disabled for angular/fire by default but it is not and there is no way to turn it off. As such, #BorisD's answer is correct but he hasn't explained it too well. Here's a full example for converting valueChanges to snapshotChanges.
constructor(private afs: AngularFirestore) {}
private getSequences(collection: string): Observable<IPaddedSequence[]> {
return this.afs.collection<IFirestoreVideo>('videos', ref => {
return ref
.where('flowPlayerProcessed', '==', true)
.orderBy('sequence', 'asc')
}).valueChanges().pipe(
map((results: IFirestoreVideo[]) => results.map((result: IFirestoreVideo) => ({ videoId: result.id, sequence: result.sequence })))
)
}
Converting the above to use snapshotChanges to filter out stuff from cache:
constructor(private afs: AngularFirestore) {}
private getSequences(collection: string): Observable<IPaddedSequence[]> {
return this.afs.collection<IFirestoreVideo>('videos', ref => {
return ref
.where('flowPlayerProcessed', '==', true)
.orderBy('sequence', 'asc')
}).snapshotChanges().pipe(
filter((actions: DocumentChangeAction<any>[], idx: number) => idx > 0 || actions.every(a => a.payload.doc.metadata.fromCache === false)),
map((actions: DocumentChangeAction<any>[]) => actions.map(a => ({ id: a.payload.doc.id, ...a.payload.doc.data() }))),
map((results: IFirestoreVideo[]) => results.map((result: IFirestoreVideo) => ({ videoId: result.id, sequence: result.sequence })))
)
}
The only differences are that valueChanges changes to snapshotChanges and then add the filter DocumentChangeAction and map DocumentChangeAction lines at the top of the snapshotChanges pipe, everything else remains unchanged.
This approach is discussed here
Related
If I call valueChanges on a Firestore document that doesn't exist, it returns undefined:
this.afs.doc('bad_document_ref').valueChanges().subscribe(snapshot => {
console.log(snapshot) // undefined
});
But if I call valueChanges on the same bad ref, but I pass in the idField parameter, it returns an object with just the id:
this.afs.doc('bad_document_ref').valueChanges({ idField: 'custom_doc_id' }).subscribe(snapshot => {
console.log(snapshot) // { custom_doc_id: 'bad_document_ref' }
});
I would like for the two above examples to return the same thing. I can do this by adding a pipe:
this.afs.doc('bad_document_ref').valueChanges({ idField: 'custom_doc_id' })
.pipe(map(snapshot => {
if(!snapshot) return undefined;
if (Object.keys(snapshot).length === 1 && Object.keys(snapshot)[0] === 'custom_id_field') {
return undefined;
}
return snapshot;
}))
.subscribe(snapshot => {
console.log(snapshot) // undefined
});
Is there a reason why the first two examples don't return the same thing? It seems like the logical thing to do, for the sake of consistency. Maybe there is a reason I'm not thinking of for why they would return different values?
The valueChange() method is basically the current state of your collection. You can listen for changes on the collection’s documents by calling valueChanges() on the collection reference. It returns an Observable of data as a synchronized array of JSON objects. All Snapshot metadata is stripped and just the document data is included.
When you pass an option object with an idField key containing a string like .valueChanges({ idField: 'propertyId' }); , it returns JSON objects with their document ID mapped to a property with the name provided by idField.
When the document doesn't actually exist, you would expect it to return nothing. In the first piece of code, you are not providing idField and the document doesn't exist, the observable returned undefined, which is justified. However, when you specify idField in the second piece of code, you basically say that when you return the data, you want the id of the document to be added to it. However if there is no data, there should not be any value returned, which is what you wanted to point out and which is quite justified. In other words, if the document does not exist, ideally it should return undefined even if you specify the idField parameter.
A GitHub link pointing towards the same issue says that the appropriate behavior is addressed in version 7 api.
Another GitHub link to be followed on this.
I am using:
angularFirestore.collection<Item>('items');
Note that for the object mapped I use <Item>, so maybe you can use it in your doc.
I am trying to get a user search functionality working in my AngularFire app.
As firestore doesn't support these queries I thought it would be enough to query the fields separately
getUsersByName(searchValue: string) {
const firstNames = this.afs.collection<IUser>('user', ref => ref.orderBy('firstname').startAt(searchValue).endAt(searchValue+'\uf8ff')).valueChanges({ idField: 'id' });
const lastNames = this.afs.collection<IUser>('user', ref => ref.orderBy('lastname').startAt(searchValue).endAt(searchValue+'\uf8ff')).valueChanges({ idField: 'id' });
return concat(firstNames, lastNames);
}
This only works for the firstNames though. Only the first Observable is being used. I think I don't understand the concat operator but it's not clear to me according the docs what the current best solution would be for this problem.
you could use zip operator
const firstNames: Observable<string>
const lastNames: Observable<string>
zip(firstNames,lastNames).subscribe(
([firstName,lastName]) => { console.log(firstName,lastName);}
)
if firstNames and lastNames emit only one item, combineLatest([firstNames,lastNames]) will be more readable
great link to learn how to use these operators https://indepth.dev/posts/1114/learn-to-combine-rxjs-sequences-with-super-intuitive-interactive-diagrams
The reason this only works for first name is because of how concat works; it will only use one observable at a time until it completes, but the firestore observables are long lived and will not complete.
You should use merge instead of concat.
import { merge } from 'rxjs';
getUsersByName(searchValue: string) {
const firstNames = this.afs.collection<IUser>('user', ref => ref.orderBy('firstname').startAt(searchValue).endAt(searchValue+'\uf8ff')).valueChanges({ idField: 'id' });
const lastNames = this.afs.collection<IUser>('user', ref => ref.orderBy('lastname').startAt(searchValue).endAt(searchValue+'\uf8ff')).valueChanges({ idField: 'id' });
return merge(firstNames, lastNames);
}
Redux Toolkit is giving me mutation errors when trying to update state on a nested array, which I thought it was using immer to get around this and simplify the reducers.
My store looks like :
state -> forms -> sections
I want to add a section to an existing form.
My action takes a form and a section
the reducer looks like
let intialState={
forms:[]
}
const FormsReducer = createReducer(intialState, {
ADD_SECTION: (state, action) => {
const index = state.forms.findIndex(f => f.id === action.form.id);
state.forms[index].__formSections.push(action.payload);
},
A state mutation was detected inside a dispatch, in the path: FormsReducer.forms.0.__formSections.0
Yet according to the redux-toolkit documentation is should be possible to "write "mutative" immutable update logic"...
What am I doing wrong and how can I fix it?
If you return it without mutating from reducer the error will not occur
const FormsReducer = createReducer(intialState, {
ADD_SECTION: (state, action) => {
const newstate = {...state}
const index = newstate.forms.findIndex(f => f.id === action.form.id);
newstate.forms[index].__formSections.push(action.payload);
return newstate
},
I want to update the itemsToUpdate collection.
This collection is already used in a query thus the resulting entities are already tracked in the context local property.
What is the most efficient way of overriding properties of the context.items.Local property from the itemsToUpdate collection?
private async Task<IEnumerable<item>> GetitemsAsync(IEnumerable<item> itemIds)
{
return await context.items.Where(t => itemIds.Select(x => x.Id).Contains(t.Id)).ToListAsync();
}
public async Task Update(...)
{
// Update
var queryUpdateitems = await GetitemsAsync(itemsToUpdate);
bool canUpdate = queryUpdateitems.All(t => t.UserId == userId);
if (!canUpdate)
{
throw new NotAuthorizedException();
}
else
{
// update here the itemsToUpdate collection
}
context.SaveChangesAsync();
}
In your case, you know that you have to update all these items, you just want to make sure that current user can update all items (by comparing Item.UserId). Instead of fetching all the existing items from database to make the check, you can query database to give result of the check and then you can just send update to database if check is true.
var itemIds = itemsToUpdate.Select(x => x.Id).ToList();
var canUpdate = await db.Blogs.Where(b => itemIds.Contains(b.Id)).AllAsync(t => t.UserId == userId);
if (canUpdate)
{
db.UpdateRange(itemsToUpdate);
}
else
{
throw new NotSupportedException();
}
await db.SaveChangesAsync();
Here, you have to make list of itemIds first because EF cannot inline list of items in a query and will do evaluation on client otherwise. That means EF is fetching whole table. Same is true for your GetitemsAsync method. It also queries whole table. Consider creating itemIds locally in that method too.
Once you pass in List<int> in the method EF will be happy to inline it in query and for query of canUpdate it will sent single query to database and fetch just true/false from database. Then you can use UpdateRange directly since there are nomore tracking records. Since it does not fetch all items from database, it will be faster too.
I want to fetch the candidate and the work exp where it is not deleted. I am using repository pattern in my c# app mvc.
Kind of having trouble filtering the record and its related child entities
I have list of candidates which have collection of workexp kind of throws error saying cannot build expression from the body.
I tried putting out anonymous object but error still persist, but if I use a VM or DTO for returning the data the query works.
It's like EF doesn't like newing up of the existing entity within its current context.
var candidate = dbcontext.candidate
.where(c=>c.candiate.ID == id).include(c=>c.WorkExperience)
.select(e=>new candidate
{
WorkExperience = e.WorkExperience.where(k=>k.isdeleted==false).tolist()
});
Is there any workaround for this?
You cannot call ToList in the expression that is traslated to SQL. Alternatively, you can start you query from selecting from WorkExperience table. I'm not aware of the structure of your database, but something like this might work:
var candidate = dbcontext.WorkExperience
.Include(exp => exp.Candidate)
.Where(exp => exp.isdeleted == false && exp.Candidate.ID == id)
.GroupBy(exp => exp.Candidate)
.ToArray() //query actually gets executed and return grouped data from the DB
.Select(groped => new {
Candidate = grouped.Key,
Experience = grouped.ToArray()
});
var candidate =
from(dbcontext.candidate.Include(c=>c.WorkExperience)
where(c=>c.candiate.ID == id)
select c).ToList().Select(cand => new candidate{WorkExperience = cand.WorkExperience.where(k=>k.isdeleted==false).tolist()});