I'm trying to update 2 firebase collections that will contain an array element that is the same.
For example, I'm building a job app, so when a user creates a job, it pushes that job object into a firebase collection called alljobs under a document called alljobs. In addition, the same job is pushed to a firebase collection called created jobs. Where each user on the app has their individual created jobs, each doc is named the users id.
Is there an easy way to update this specific job in both alljobs collection and the createdjobs collection?
For example, my approach of doing it would be like this.
Individual Job component (obtained by previously mapping through all the jobs)
const [userjobs, setUserjobs] = useState([])
const {job, createdjobs} = props
function updateJob(){
createdjobs?.map(job1=>{
if(job1.jobid===job.jobid){
const jobindex = createdjobs.indexOf(job1)
createdjobs[jobindex].jobtitle = 'New title'
db.collection('createdjobs').doc(user.uid).update({
jobs: createdjobs
})
}
})
}
I'll basically have to repeat this same process to update once again the job that has just been updated in the createdjobs collection. This gets repetitive and messy. So looking for a solution to this. By mapping through alljobs this time.
useEffect(()=>{
db.collection('alljobs').doc('alljobs').onSnapshot(snap=>{
setAlljobs(snap.data().jobs)
})
},[])
There is no shortcut for your problem I think. But I suggest you to write a sync function to Firebase Function.
It will watch changes of one source and sync to others. So that your logic code only needs to manage one source of trust.
As #Thanh Le suggested you can write a Google Cloud Function to fulfill this purpose. In cloud functions there is a function type named triggers. You can use this triggers.
Cloud Function triggers
We can write functions which will automatically trigger when the specfied document or set of documents,
onCreate - Trigger when document creating
onUpdate - Triggered when a document already exists and has any value changed.
onDelete - Trigger when document deleting
onWrite - Triggered when onCreate, onUpdate or onDelete is triggered.
From these triggers you can use onWrite Trigger to to implement the function.
exports.updateAllJobsTrigger = functions.firestore.document('createdJob/{userId}')
onWrite(async (change, context) => {
// Check if document is deleted
if (!change.after.exists) {
logger.log('Document not existing. Function exited.');
return;
}
const allJobsRef = admin.firestore().collection('alljobs').doc('alljobs');
// Check if document created
if (!change.before.exists) {
try {
// This is a newly created document. Therefore newjob should be in first element
const newJob = change.after.data().jobs[0];
const data = (await allJobsRef.get()).data();
if (data) {
const jobs = data.jobs;
await allJobsRef.update({
jobs: [...jobs, newJob]
});
logger.info('Job added to All jobs queue.');
}
} catch (exception) {
logger.error(exception)
}
return;
}
try {
// This is a updating document.newly added job is in the last element of the array
const newJob = change.after.data().jobs[change.after.data().jobs.length - 1];
const data = (await allJobsRef.get()).data();
if (data) {
const jobs = data.jobs;
await allJobsRef.update({
jobs: [...jobs, newJob]
});
logger.info('Job added to All jobs queue.');
}
} catch (exception) {
logger.error(exception)
}
});
As #Nimna Perera said, you can use Cloud Functions to solve this issue. Your CF should be triggered when a document is updated, created or deleted (so the onWrite option). Another way to do this is through transactions, when you need to read and write the documents or batched writes when you only need to write in one or various documents. In both cases you are not limited to a single collection, so it should work for your issue.
Related
I am using express to create my firebase functions, and I understand how to create regular callable functions. I am lost however on the exact way to implement trigger functions for the background (i.e. onCreate, onDelete, onUpdate, onWrite), as well as how Reactjs in the frontend is supposed to receive the data.
The scenario I have is a generic chat system that uses react, firebase functions with express and realtime database. I am generally confused on the process of using triggers for when someone sends a message, to update another user's frontend data.
I have had a hard time finding a tutorial or documentation on the combination of these questions. Any links or a basic programmatic examples of the life cycle would be wonderful.
The parts I do understand is the way to write a trigger function:
exports.makeUppercase = functions.database.ref('/messages/{pushId}/original')
.onWrite((change, context) => {
// Only edit data when it is first created.
if (change.before.exists()) {
return null;
}
// Exit when the data is deleted.
if (!change.after.exists()) {
return null;
}
// Grab the current value of what was written to the Realtime Database.
const original = change.after.val();
console.log('Uppercasing', context.params.pushId, original);
const uppercase = original.toUpperCase();
// You must return a Promise when performing asynchronous tasks inside a Functions such as
// writing to the Firebase Realtime Database.
// Setting an "uppercase" sibling in the Realtime Database returns a Promise.
return change.after.ref.parent.child('uppercase').set(uppercase);
});
But I don't understand how this is being called or how the data from this reaches frontend code.
Background functions cannot return anything to client. They run after a certain event i.e. onWrite() in this case. If you want to update data at /messages/{pushId}/original to other users then you'll have to use Firebase Client SDK to listen to that path:
import { getDatabase, ref, onValue} from "firebase/database";
const db = getDatabase();
const msgRef = ref(db, `/messages/${pushId}/original`);
onValue(msgRef, (snapshot) => {
const data = snapshot.val();
console.log(data)
});
You can also listen to /messages/${pushId} with onChildAdded() to get notified about any new node under that path.
I have a collection called list which I'm trying to order by 3 different fields: important, unimportant and date, so the unimportant come first (they'll be at the bottom of the list, important the last, and all that sorted by timestamp.
If i query to order my docs by any of the above on its own, then it works, trouble starts when I try to put them together as per firestore documentation. So I have the following code:
const q = query(listRef, orderBy("important", "desc"), orderBy("unimportant"), orderBy("date"));
Which gets me Uncaught Error in snapshot listener. This is how i get my data from firestore:
const getData = () => { // get data from firestore to app
onSnapshot(q, (snapshot) => {
firestoreList = [];
firestoreIds = [];
snapshot.docs.forEach((doc) => {
firestoreList.push({ ...doc.data(), id: doc.id });
!firestoreIds.includes(doc.id) && firestoreIds.push(doc.id);
});
if (firestoreList.length === 0) {
setItems(items.concat(newItem));
} else {
setItemIds(firestoreIds);
setItems(firestoreList);
}
});
}
useEffect(() => {
getData();
}, []);
I'm using onSnapshot, because i need the user to be able to add, remove and do other stuff with data and see the outcome reflected immediately for them and for other users who'll be using the app simultaneously.
Ordering/filtering on multiple fields requires that your database contains a so-called composite index on those fields. And unlike single-field indexes, which are created automatically, composite indexes are only created when you explicitly tell the database to do so.
If you log the warning/error message you get, it contains a long direct link to the Firestore console to create the exact index the query needs. The link has all details already filled in, so all you have to do is click the link and then click the button to start creating the index.
Also see:
Firestore order by two fields
How to query one field then order by another one in Firebase cloud Firestore?
the Firestore documentation on ordering a Firestore query on multiple fields.
I'm developing an app using React Native that allows you to create your own checklists and add items to them.
For example you'd have "Create Checklist", and inside that you'll have the option to "Add Item", "Delete Item" "Edit Item", basic CRUD methods etc.
It's going to be completely offline but I'm wondering what the best approach to storing this data locally would be.
Should I be using a DB such as firebase? I have read that it is overkill and to use something like Redux but I'm not sure if the latter will accomplish everything I need. As long as it's storing data which can be edited, and will save on the user's device (with minimal effort) it sounds good to me.
Would appreciate some input on this, thanks!
You could use AsyncStorage for persisting data locally on the user's phone. It is a simple persistent key-value-storage.
Each checklist is most likely an array of JS objects. The documentation provides an example on how to store objects.
const storeData = async (value) => {
try {
const jsonValue = JSON.stringify(value)
await AsyncStorage.setItem('#storage_Key', jsonValue)
} catch (e) {
// saving error
}
}
The value parameter is any JS object. We use JSON.stringify to create a JSON string. We use AsyncStorage.setItem in order to persist the data. The string #storage_Key is the key for the object. This could be any string.
We retrieve a persisted object as follows.
const getData = async () => {
try {
const jsonValue = await AsyncStorage.getItem('#storage_Key')
return jsonValue != null ? JSON.parse(jsonValue) : null;
} catch(e) {
// error reading value
}
}
Both examples are taken from the official documentation.
Keep in mind that this functionality should be used for persistence only. If the application is running, you should load the complete list, or parts of the list if it is very large, in some sort of application cache. The implementation for this functionality now heavily depends on how your current code looks like. If you have a plain view, then you could access the local storage in an effect and just store it in a local state.
function MySuperList() {
const [list, setList] = useState([]);
React.useEffect(() => {
// retrieve data using the above functionality and set the state
}, [])
// render list
return (...)
}
I would implement some sort of save button for this list. If it is pressed, then we persist the data in the local storage of the phone.
I am making a mobile app using flutter with firebase as my backend.
I have a collection of user document that stores user information. one of the fields is an array of references (reference documents in another collection) which I want to use in an operation like batch that in that would then allow be to read all the documents.
I know batch only allows writes to the database, My second option would be Transaction, which requires writes after reads which I am trying to avoid.
Is there a way to read multiple documents in one operation without having to use Transaction?
Firestore doesn't offer a formal batch read API. As Frank mentions in his comment, there is a way to use IN to fetch multiple documents from a single collection using their IDs. However, all of the documents must be in the same collection, and you can't exceed 10 documents per query. You might as well just get() for each document individually, as the IN query has limitations, and isn't guaranteed to execute any faster than the individual gets. Neither solution is guaranteed to be "consistent", so any one of the documents fetched could be "more fresh" than the others at any given moment in time.
If you know the document IDs and the collection paths of the documents needed to be fetched, you could always use the getAll() method which is exposed in the firebase Admin SDK (at least for Node.js environments).
Then, for example, you could write an HTTPS Callable Function that would accept a list of absolute document paths and perform a "batch get" operation on them using the getAll() method.
e.g.
// Import firebase functionality
const functions = require('firebase-functions');
const admin = require('firebase-admin');
// Configure firebase app
admin.initializeApp(functions.config().firebase);
// HTTPS callable function
exports.getDocs = functions.https.onCall((data, context) => {
const docPathList = data.list; // e.g. ["users/Jkd94kdmdks", "users/8nkdjsld", etc...]
const firestore = admin.firestore();
var docList = [];
for (var i = 0; i <= docPathList.length - 1; i++) {
const docPath = docPathList[i];
const doc = firestore.doc(docPath);
docList.push(doc);
}
// Get all
return firestore.getAll(...docList)
.then(results => {
return { data : results.map(doc => doc.data()) };
})
.catch(err => {
return { error : err };
})
});
Not sure what the limit (if any) is for the number of documents you can fetch using getAll(), but I do know my application is able to fetch at least 50 documents per call successfully using this method.
Firestore has a REST API that allows you to do batch GETs with document paths that may be what you need.
See https://firebase.google.com/docs/firestore/reference/rest/v1beta1/projects.databases.documents/batchGet
I have a relay mutation that posts some data to my server. My app shouldn't wait for the response before continuing.
I know I can execute arbitrary queries with the following:
const query = Relay.createQuery(Relay.QL`
query {
viewer {
searchInterests(prefix: $prefix, first: 10) {
edges {
node {
id
name
}
}
}
},
}
`, {prefix: input});
Relay.Store.primeCache({query}, readyState => {
if (readyState.done) {
// When all data is ready, read the data from the cache:
const data = Relay.Store.readQuery(query)[0];
...
}
How can I fire off mutations asynchronously without my app waiting for the response?
When designing a fat query, consider all of the data that might change as a result of the mutation – not just the data currently in use by your application. We don't need to worry about overfetching; this query is never executed without first intersecting it with a ‘tracked query’ of the data our application actually needs. If we omit fields in the fat query, we might observe data inconsistencies in the future when we add views with new data dependencies, or add new data dependencies to existing views.