I'm trying to retrieved chats that a particular user is part of and that works but when I'm subscribing to that query and someone starts a chat me or I start a chat with a new person, it doesn't update. When I manually reload the page, it gets the latest chats so I think my query works but subscribing to it doesn't.
Here's my query:
let query = new Parse.Query("Chat");
query = query.containedIn("members", [Parse.User.current()]);
And here is the subscription:
let subscription = query.subscribe();
subscription.on("create", chat => addChatToView(chat))
I tried to do it manually by omitting the second line and subscribe to whole table and using lodash to somehow filter the results.
Is there any solution to this aside from doing it manually?
Related
I am using Apollo Client without React, just plain ol JS. I have a classic table and modal that adds things to the backend. Once I add the thing using client.mutate() I'd like to update the table. If the table is not on the last page, it doesn't really matter, the user will eventually click there to get to the new row. But if the user is on the last page or has visited the last page at any point, going back to that page will not display the new row.
In React I was able to do something like
useMyMutation({
variables: {},
refetchQueries: [getOperationName(SomeDocument)]
})
And what this did was refetch the provided query name with its last used variables. I'd like to do something similar and I've been reading the docs and trying this and that but can't even get a query to trigger on the network.
client.mutate(
mutation: MyMutation,
variables: {a:1},
refetchQueries: (e: any) => "all", // nothing I put here ever does anything
)
I am currently working on adding Auth0 to a Vue.js/Node.js application and so far I have figured out how to allow users to register and log in (to /callback) and that seems to be working fine. However, I have manually added (will be automatic later on) some data to the user metadata section. I have the below code as a rule that is turned on. I can’t seem to get access to the data on the Vue.js end of things. What I’d like is to be able to get the user data and user metadata so I can store it in my front end.
Rule code
function (user, context, callback) {
const namespace = 'account_signup_type/';
const namespace2 = 'account_type';
context.idToken[namespace + 'is_new'] = (context.stats.loginsCount === 1);
context.idToken[namespace2] = user.account_type;
context.idToken.user = user;
callback(null, user, context);
}
Code I am trying in my Vue.js front end
getIdTokenClaims(o) {
return this.auth0Client.getIdTokenClaims(o);
}
Currently, this returns undefined
I ended up figuring it out, there was no namespace being created in the id_token which resulted in it not properly passing the data through to the Vue .js app. I added a namespace using a web address format with the domain extension cut off and it now works.
How to get all the books of a specific author from my database?
Here is a snapshot of my database, i want to get "Colson Whitehead"
for web development, javascript.
To get all books by author Colson Whitehead, you do a query like this:
var query = firebase.database().ref("books").orderByChild("author").equalTo("Colson Whitehead");
query.on("value", function(snapshot) {
snapshot.forEach(function(bookSnapshot) {
console.log(bookSnapshot.key+": "+bookSnapshot.val());
});
})
This callback will get called initially and then every time something about the books by Colson Whitehead changes. If you only want the initial call, use once instead of on.
When trying to pull data from a MySQL database, I can do something like:
SELECT * FROM users ORDER BY id WHERE vehicle = car
That should get me all the users that drives a car and not show users that drives a motorcycle for instance.
Is there something like this for Firebase? I can only retrieve specific data from one user?
My firebase database is like this: user -> user info (name, age, vehicle etc..)
I want to query every user that drives a car and display them in a row. How do I do that?
I have tried the following, but I didn't succeed with what I tried to do, since after users the users id is the next child. Is there a way to query past that?
var recents = firebase.database().child('users').orderByChild('department').equalTo(department);
recents.on('child_added', function(snapshot) {
var countOfUserInDepartment = snapshot.count;
document.querySelector("#cphCount").innerHTML = countOfUserInDepartment;
});
There are no count queries (nor other aggregation queries) in the Firebase Database. Your options are:
Retrieve all data matching your query and count client-side
Keep a separate count-node that you update whenever you add/remove items.
For #2 you may find it convenient to use Cloud Functions, for which there an an example of keeping such a counter.
Also see:
Firebase count group by
Database-style Queries with Firebase
In Firebase, is there a way to get the number of children of a node without loading all the node data?
How to get size of an element/list in Firebase without get it all?
I have a node in Firebase getting continually updated with information from a logfile. The node is lines/ and each child of lines/ is from a post() so it has a unique ID.
When a client first loads, I want to be able to grab the last X number of entries. I expect I'll do this with once(). From then on, however, I want to use an on() with child_added so that I get all new data. However, child_added gets all data stored in the Firebase and, after the initial setup, only want the new stuff.
I see that I can add a limitToLast() on the on(), but, if I say limitToLast(1) and a flood of entries come in, will my app still get all the new entries? Is there some other way to do this?
You need to include a timestamp property and run a query.
// Get the current timestamp
var now = new Date().getTime();
// Create a query that orders by the timestamp
var query = ref.orderByChild('timestamp').startAt(now);
// Listen for the new children added from that point in time
query.on('child_added', function (snap) {
console.log(snap.val()
});
// When you add this new item it will fire off the query above
ref.push({
title: "hello",
timestamp: Firebase.ServerValue.TIMESTAMP
});
The Firebase SDK has methods for ordering, orderByChild() and methods for creating a range startAt(). When you combine the two you can limit what comes back from Firebase.
I think there is a problem in #David East's solution. He is using the local timestamp which may cause problem if the time is not accurate in client device. Here is my suggested solution (iOS Swift):
Using observeSingleEvent to get the complete data set
Then returned it in reversed order by reversed()
Get the last timestamp by for example data[0].timestamp
Using queryStarting for timestamp
self._dbref.queryOrdered(byChild: "timestamp").queryStarting(atValue: timestamp+1)
.observe(.childAdded, with: {
snapshot in
print(snapshot.value)
})
You have the right idea. child_added should be called only for the new nodes. Without source code it's hard to tell why you get all the data in your child_added event.
You can check the chat demo app to see how they load new chat messages. The use case sounds similar.
https://github.com/firebase/firechat/blob/master/src/js/firechat.js#L347
Here's temporary but quick solution:
// define a boolean
var bool = false;
// fetch the last child nodes from firebase database
ref.limitToLast(1).on("child_added", function(snap) {
if (bool) {
// all the existing child nodes are restricted to enter this area
doSomething(snap.val())
} else {
// set the boolean true to doSomething with newly added child nodes
bool = true;
}
});
Disadvantage: It will load all the child nodes.
Advantage: It will not process existing child nodes but just the newly added child nodes.
limitToLast(1) will do the work.