It seems im using async wrong, can anybody spot what I am doing wrong?
This is the function I am waiting on:
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
export async function firebaseAcceptTradeOffer(tradeOfferID, userData) {
var tradeInstanceID;
var senderID;
var receiverID;
var senderItemsTemp;
var receiverItemsTemp;
var response;
var tradeOffer = db.collection("tradeOffers").doc(tradeOfferID);
return tradeOffer
.get()
.then((doc) => {
senderItemsTemp = doc.data().sendersItems;
receiverItemsTemp = doc.data().receiversItems;
senderID = doc.data().senderID;
receiverID = doc.data().receiverID;
})
.then(() => {
var itemInTrade = false;
senderItemsTemp.forEach((item) => {
db.collection("listings")
.doc(item.itemID)
.get()
.then((doc) => {
if (doc.data().status !== "listed") {
itemInTrade = true;
}
})
.then(() => {
receiverItemsTemp.forEach((item) => {
db.collection("listings")
.doc(item.itemID)
.get()
.then((doc) => {
if (doc.data().status !== "listed") {
itemInTrade = true;
}
})
.then(() => {
if (itemInTrade) {
tradeOffer.update({
status: "declined",
});
return false;
} else {
db.collection("trades")
.add({
tradeOfferID: tradeOfferID,
senderTradeStatus: {
created: true,
sentToSeekio: "current",
inspection: false,
sentToPartner: false,
},
receiverTradeStatus: {
created: true,
sentToSeekio: "current",
inspection: false,
sentToPartner: false,
},
postagePhotos: [],
inspectionPhotos: [],
senderPaid: false,
receiverPaid: false,
senderUploadedProof: false,
receiverUploadedProof: false,
senderID: senderID,
receiverID: receiverID,
messages: [
{
message: `Trade created. A representative, will message this chat shortly with instructions and postage address. If you would like more information about the trading process, head to seekio.io/help. Thank you for using Seekio!`,
sender: "System",
timestamp: firebase.firestore.Timestamp.fromDate(
new Date()
),
},
],
})
.then((docRef) => {
tradeInstanceID = docRef.id;
tradeOffer
.set(
{
status: "accepted",
tradeInstanceID: docRef.id,
},
{ merge: true }
)
.then(() => {
var receiver = db.collection("users").doc(senderID);
var notification = {
from: auth.currentUser.uid,
fromUsername: userData.username,
type: "tradeOfferAccepted",
time: firebase.firestore.Timestamp.fromDate(
new Date()
),
seen: false,
};
receiver
.update({
notifications: firebase.firestore.FieldValue.arrayUnion(
notification
),
})
.then(() => {
response = {
sendersItems: senderItemsTemp,
receiversItems: receiverItemsTemp,
};
return response;
});
});
})
.catch((err) => console.log(err));
}
});
});
});
});
});
}
And here is where I am calling it:
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
async function acceptTradeOffer() {
var tradeOfferID = currentTradeFocus;
var senderID = "";
setLoading("loading");
if (userData !== null && tradeOfferID !== "") {
const response = await firebaseAcceptTradeOffer(
currentTradeFocus,
userData
);
console.log(
"RESPONSE FROM FIREBASE SERVICE>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>: ",
response
);
if (!response) {
setErrorMsg("One of the selected items is no longer available.");
} else if (
response.sendersItems !== null &&
response.receiversItems !== null
) {
setSenderItems(response.sendersItems);
setReceiverItems(response.receiversItems);
toggleConfirmScreen("cancel");
setLoading("idle");
setItemsSet(true);
}
fetch(
"https://europe-west2-seekio-86408.cloudfunctions.net/sendMail?type=tradeUpdate&userID=" +
senderID
).catch((err) => {
console.log(err);
setLoading("idle");
});
}
}
So basically I want to go and check if any of the items in this 'trade' are not equal to 'listed' (which means they are not available, I want to return false, if not, then I return the array of items so the trade can continue.
EDIT: I've tried to rejig it all and it's half working. A top level look at what I am trying to do:
User wants to accept a trade offer for some items >
Check through all items to make sure they are available and not sold >
If so, accept the trade >
Then once its accepted, go and cancel all remaining trade offers that include items from this accepted trade, cause they are not available anymore.
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
export async function firebaseAcceptTradeOffer(tradeOfferID, userData) {
console.log(
"----- starting firebaseAcceptTradeOffer--------- ",
unavailableItem
);
//==============
var tradeInstanceID;
var senderID;
var receiverID;
var senderItemsTemp;
var receiverItemsTemp;
var unavailableItem = false;
var response;
var itemsArray;
var notListed = false;
//==============
var tradeOffer = db.collection("tradeOffers").doc(tradeOfferID);
unavailableItem = tradeOffer
.get()
.then((doc) => {
senderID = doc.data().senderID;
receiverID = doc.data().receiverID;
itemsArray = doc.data().sendersItems.concat(doc.data().receiversItems);
})
.then(() => {
itemsArray.forEach((item) => {
db.collection("listings")
.doc(item.itemID)
.get()
.then((doc) => {
if (doc.data().status !== "listed") {
notListed = true;
}
});
});
})
.then(() => {
return notListed;
});
console.log(
"-----unavailableItem at the end of method --------- ",
unavailableItem
);
//^^^^^^^^^^ here i am getting a promise result of false (which is correct) but HOW CAN I ACCESS IT
if (unavailableItem) {
tradeOffer.update({
status: "declined",
});
return false;
} else {
response = await createTrade(
tradeOffer,
tradeOfferID,
senderID,
receiverID,
userData.username
);
console.log("response from createTrade", response);
return response;
}
}
I am getting a promise object back with the value false above. False is correct value I am expecting, but how can I access it? its in the form of a promise object?
I have some time on my hands, so let's break this down.
Notes on Variables
If you aren't using TypeScript (and even if you are), I highly recommend inserting the type into the name of your variables.
db # ✔ by convention, either firebase.database() or firebase.firestore()
tradeOffer # ❓ type unclear, could be a number, an object, a string, etc
tradeOfferDocRef # ✔ a DocumentReference
trades # ❓ type unclear, plural implies a collection of some sort
tradesColRef # ✔ a CollectionReference
You may also encounter these:
doc # ❓ by convention, a DocumentSnapshot, but with unknown data
tradeDoc # ✔ implies a DocumentSnapshot<TradeData> (DocumentSnapshot containing trade data)
When using just doc, you need to look around where its used for context on what this DocumentSnapshot contains.
db.collection('trades').doc(tradeOfferID).get()
.then((doc) => { // contents implied to be TradeData
const data = doc.data();
});
// or
tradeDocRef.get()
.then((doc) => { // contents implied to be TradeData
const data = doc.data();
});
You should rename doc as appropriate, especially when using async/await syntax, so you don't end up in situations like:
const doc = await db.collection('trades').doc(tradeOfferID).get();
/* ... many lines ... */
const senderID = doc.get("senderID"); // what was doc again?
As you've tagged reactjs in your question, this implies you are using modern JavaScript.
Ditch any use of var and replace it with the block-scoped versions: const (prevents reassigning the variable) or let (similar to var, but not quite). These are safer and prevents the chances of accidentally overwriting something you shouldn't.
You can also make use of Object destructuring to assign your variables.
const senderID = doc.data().senderID;
const receiverID = doc.data().receiverID;
const itemsArray = doc.data().sendersItems.concat(doc.data().receiversItems);
can become:
const { senderID, receiverID, sendersItems, receiversItems } = doc.data();
const itemsArray = sendersItems.concat(receiversItems);
If you ever need only a single property out of a document, you should use DocumentSnapshot#get() instead of DocumentSnapshot#data() so it will parse only the field you want instead of the whole document's data.
function getUserAddress(uid) {
return firebase.firestore()
.collection('users')
.doc(uid)
.get()
.then(userDoc => userDoc.get("address")); // skips username, email, phone, etc
}
Notes on Promises
var senderID;
var receiverID;
var itemsArray;
tradeOfferDocRef
.get()
.then((doc) => {
senderID = doc.data().senderID;
receiverID = doc.data().receiverID;
itemsArray = doc.data().sendersItems.concat(doc.data().receiversItems);
})
.then(() => {
/* use results from above */
});
While the above code block functions as intended, when you have many of these variables like this as you do, it becomes unclear when and where they are set.
It also leads to problems like this where you think the variable has a value:
var senderID;
var receiverID;
var itemsArray;
tradeOfferDocRef
.get()
.then((doc) => {
// this line runs after the line below
senderID = doc.data().senderID;
receiverID = doc.data().receiverID;
itemsArray = doc.data().sendersItems.concat(doc.data().receiversItems);
});
// this line before the line above
console.log(senderID); // will always log "undefined"
This can be avoided in one of three ways:
Returning data to pass through to the next handler (you wouldn't use this for this example, only if the next then() handler is elsewhere):
tradeOfferDocRef
.get()
.then((doc) => {
const { senderID, receiverID, sendersItems, receiversItems } = doc.data();
const itemsArray = sendersItems.concat(receiversItems);
return { senderID, receiverID, itemsArray }; // pass to next step
})
.then((neededData) =>
/* use neededData.senderID, neededData.receiverID, etc */
});
Using the data within the same handler:
tradeOfferDocRef
.get()
.then((doc) => {
const { senderID, receiverID, sendersItems, receiversItems } = doc.data();
const itemsArray = sendersItems.concat(receiversItems);
/* use results from above */
});
Using async-await syntax:
const tradeDoc = await tradeOfferDocRef.get();
const { senderID, receiverID, sendersItems, receiversItems } = tradeDoc.data();
const itemsArray = sendersItems.concat(receiversItems);
/* use results from above */
Writing to Firestore
Your current code consists of the following steps:
1. Get the trade offer document</li>
2. If successful, pull out the sender and receiver's IDs, along with any items in the trade
3. If successful, do the following for each item in the sender items array:
a) Check if any of the sender's items are unavailable</li>
b) If successful, do the following for each item in the receiver items array:
- If **any item** was unavailable prior to this, decline the trade & return `false`.
- If all items **so far** are available, do the following:
a) Create a document containing information about the trade with the needed data
b) If successful, edit the trade offer document to accept it
c) If successful, create a notification for the receiver
d) If successful, return the traded items
e) If any of a) to d) fail, log the error and return `undefined` instead
4. Return `undefined`
In the above steps, you can see some problems with your promise chaining. But aside from that, you can also see that you create and edit documents one-by-one instead of all-at-once ("atomically"). If any of these writes were to fail, your database ends up in an unknown state. As an example, you could have created and accepted a trade, but failed to create the notification.
To atomically write to your database, you need to use a batched write where you bundle a bunch of changes together and then send them off to Firestore. If any of them were to fail, no data is changed in the database.
Next, you store a user's notifications inside of their user document. For a small number of notifications this is fine, but do you need to download all of those notifications if you wanted to pull just an address or phone number like in the example in the above section? I recommend splitting them out into their own document (such as /users/{someUserId}/metadata/notifications), but ideally their own collection (such as /users/{someUserId}/notifications/{someNotificationID}). By placing them in their own collection, you can query them and use QuerySnapshot#docChanges to synchronize changes and use Cloud Firestore triggers to send push notifications.
Refactored Function
1. Get the trade offer document</li>
2. Once the retrieved, do the following depending on the result:
- If failed or empty, return an error
- If successful, do the following:
a) Pull out the sender and receiver's IDs, along with any items in the trade.
b) For each item in the trade, check if any are unavailable and once the check has completed, do the following depending on the result:
- If any item is unavailable, do the following:
a) Decline the trade
b) Return the list of unavailable items
- If all items are available, do the following:
a) Create a new write batch containing:
- Create a document about the trade
- Edit the trade offer document to accept it
- Create a notification for the receiver
b) Commit the write batch to Firestore
c) Once the commit has completed, do the following depending on the result:
- If failed, return an error
- If successful, return the traded items and the trade's ID
Because the steps here depend on each other, this is a good candidate to use async/await syntax.
To see this in action, closely study this:
import * as firebase from "firebase-admin";
// insert here: https://gist.github.com/samthecodingman/aea3bc9481bbab0a7fbc72069940e527
async function firebaseAcceptTradeOffer(tradeOfferID, userData) {
const tradeOfferDocRef = db.collection("tradeOffers").doc(tradeOfferID);
const tradeDoc = await tradeOfferDocRef.get();
const { senderID, receiverID, sendersItems, receiversItems } =
tradeDoc.data();
const itemsArray = sendersItems.concat(receiversItems);
// TODO: Check if this is an accurate assumption
if (sendersItems.length == 0 || receiversItems.length == 0) {
success: false,
message: "One-sided trades are not permitted",
detail: {
sendersItemsIDs: sendersItems.map(({ itemID }) => itemID),
receiversItemsIDs: receiversItems.map(({ itemID }) => itemID),
},
};
const listingsColQuery = db
.collection("listings")
.where("status", "==", "listed");
const uniqueItemIds = Array.from(
itemsArray.reduce(
(set, { itemID }) => set.add(itemID),
new Set()
)
);
const foundIds = {};
await fetchDocumentsWithId(
listingsColQuery,
uniqueItemIds,
(listingDoc) => {
// if here, listingDoc must exist because we used .where("status") above
foundIds[listingDoc.id] = true;
}
);
const unavailableItemIDs = uniqueItemIds
.filter(id => !foundIds[id]);
if (unavailableItems.length > 0) {
// one or more items are unavailable!
await tradeOfferDocRef.update({
status: "declined",
});
return {
success: false,
message: "Some items were unavailable",
detail: {
unavailableItemIDs,
},
};
}
const tradeDocRef = db.collection("trades").doc();
const tradeInstanceID = tradeDocRef.id;
const batch = db.batch();
batch.set(tradeDocRef, {
tradeOfferID,
senderTradeStatus: {
created: true,
sentToSeekio: "current",
inspection: false,
sentToPartner: false,
},
receiverTradeStatus: {
created: true,
sentToSeekio: "current",
inspection: false,
sentToPartner: false,
},
postagePhotos: [],
inspectionPhotos: [],
senderPaid: false,
receiverPaid: false,
senderUploadedProof: false,
receiverUploadedProof: false,
senderID,
receiverID,
messages: [
{
message: `Trade created. A representative, will message this chat shortly with instructions and postage address. If you would like more information about the trading process, head to seekio.io/help. Thank you for using Seekio!`,
sender: "System",
timestamp: firebase.firestore.Timestamp.fromDate(new Date()),
},
],
});
batch.set(
tradeOfferDocRef,
{
status: "accepted",
tradeInstanceID,
},
{ merge: true }
);
const receiverNotificationRef = db
.collection("users")
.doc(senderID)
.collection("notifications")
.doc();
batch.set(receiverNotificationRef, {
from: auth.currentUser.uid,
fromUsername: userData.username,
type: "tradeOfferAccepted",
time: firebase.firestore.Timestamp.fromDate(new Date()),
seen: false,
});
await batch.commit();
return {
success: true,
message: "Trade accepted",
detail: {
tradeID: tradeInstanceID,
senderItems,
receiversItems,
},
};
}
Usage:
try {
const tradeResult = await firebaseAcceptTradeOffer(someTradeId);
} catch (err) {
// if here, one of the following things happened:
// - syntax error
// - database read/write error
// - database rejected batch write
}
In general, when you are returning a promise where it can't be resolved you must await its result. Additionally, you must be returning a value from within a promise then chain, at minimal the last .then() needs to be returning a value, this can also be done within a .finally() method.
Using Get from any firebase resource, realtime, firestore, and storage are all Async processes and must be awaited. in your case, you are missing an await for the return:
var tradeOffer = db.collection("tradeOffers").doc(tradeOfferID);
return tradeOffer
and you don't appear to be returning anything inside your .then() statements, I would suggest a complete rewrite of what you are trying to so you are returning values as they are needed.
I tried to getting result using mssql database using mssql npm and push it to an array. It seems that response will return an empty array outside of the map function, your help will be much appreciated, thank you.
module.exports = {
someRouteHandler: async function(req, res, next) {
const fileStream = await readFileFromS3(req.body.filename); //a function to read file from AWS S3
if (req.body.productName === "Nike" && type === "Male") {
const result = await getBrandInformation(req.body, fileStream); //this function will parse data from the file and return object result
const { brandInformation, brandItems } = result;
const noneDuplicateArrayContainer = [];
const duplicateArrayContainer = [];
for ( const { itemNumber } of brandItems ) {
let items = await getMatchingList(itemNumber); // will query to database if itemNumber has duplicate or none
if (items.length > 1) {
items.map(async({ identifier }) => {
//if identifier not null query cost
if (identifier) {
let cost = await queryCostToDb(identifier); //will query cost from database
duplicateArrayContainer.push({
brandItems, identifier, cost
})
//if identifier is null no cost to save
} else {
duplicateArrayContainer.push({
brandItems, identifier
})
}
});
//if items length is not greater than 1 meaning no duplicate
} else {
items.map(({ identifier }) => {
let cost = await queryCostToDb(identifier); //will query cost from database
noneDuplicateArrayContainer.push({
brandItems, identifier, cost
});
})
}
}
// when sending response noneDuplicateArrayContainer and duplicateArrayContainer is [ ]
// in the console, it has data, but response is delay
return res.status(200).json({ brandInformation, noneDuplicateArrayContainer, duplicateArrayContainer })
}
}
}
I already fixed the issue, implemented await Promise.all in my code, thanks all for the help
Hello, I have made Firebase function which is watching if users matched.
All parts work, but i added one more method getUserDataById where i want to get extra data from users, it returns undefined.
So this is what i tried:
exports.UserPressesLike = functions.database
.ref('/users/{userId}/matches/{otherUserId}')
.onCreate(async (snapshot, context) => {
// Grab the current value of what was written to the Realtime Database.
const original = snapshot.val();
const userId = context.params.userId;
const matchedUserId = context.params.otherUserId;
const a = await checkUserMatch(userId, matchedUserId);
if (a === true) {
console.log('Its a match');
addNewChat(userId, matchedUserId);
//create chat for both users
} else {
console.log('There is no match');
//do nothing
console.log(a);
}
return null;
});
checkUserMatch = async (userId, matchedUserId) => {
const isLiked = await admin
.database()
.ref('/users/' + matchedUserId + '/matches/' + userId)
.once('value')
.then(snapshot => {
// let tempuserId = snapshot.val();
// if()
let isLiked = snapshot.exists();
console.log(isLiked);
return isLiked;
})
.catch(error => {
console.log(error);
return snapshot;
});
return isLiked;
};
addNewChat = async (userId, matchedUserId) => {
const user1 = await getUserDataById(userId);
const user2 = await getUserDataById(matchedUserId);
console.log(JSON.stringify('User data: ' + user1));
const snapshot = await admin
.database()
.ref('/chats')
.push({
members: { [userId]: true, [matchedUserId]: true },
[userId]: { username: [user1.username] },
[matchedUserId]: { username: [user2.username] },
});
};
getUserDataById = async userId => {
const snapshot = await admin
.database()
.ref('/users/' + userId)
.once('value')
.then(childsnapshot => {
let data = childsnapshot.val();
return data;
});
};
But I get error:
TypeError: Cannot read property 'username' of undefined
at addNewChat (/srv/index.js:93:36)
at <anonymous>
at process._tickDomainCallback (internal/process/next_tick.js:229:7)
The problem is in getUserDataById method. Because it returns undefined.
Where I made mistake?
Why I get username: { 0 : emilis} it should be username: emilis??
Part 1: getUserDataById returns undefined
You forgot return snapshot in your async function. (However, as it as a plain object, not a snapshot, I would rename the variable)
getUserDataById = async userId => {
const userData = await admin
.database()
.ref('/users/' + userId)
.once('value')
.then(childsnapshot => {
let data = childsnapshot.val();
return data;
});
return userData;
};
However, I would flatten it to the following (which is identical to the above, yet concise):
getUserDataById = userId => {
return admin
.database()
.ref('/users/' + userId)
.once('value')
.then(childsnapshot => childsnapshot.val());
};
Part 2: Why is my data returned as {username: {0: "Emilis"}}?
{0: "Emilis"} being returned as an object, not an array, is caused by how Firebase stores arrays in the Realtime Database. There is quite a comprehensive article on arrays on the Firebase Blog covering these quirks which I recommend reading. I'll summarise the key ones here.
When any array is stored in the Realtime Database it is stored in it's object form where {username: [user1.username] } will be stored as {username: {0: "someusername"} }. Because JSON is typeless, the Realtime Database no longer understands this entry to be an array. An array with multiple entries will also be stored stored as a plain object ([value1, value2] will become {0: value1, 1: value2}).
When the Firebase JavaScript SDK downloads data from the Realtime Database, it checks the keys of any objects for a mostly sequential numeric sequence (0,1,2,3,... or 0,1,3,4,...) and if detected, converts it to an array using null for any missing entries.
As {0: value1, 1: value2} contains the sequential keys 0 and 1, it will be parsed as [value1, value2].
As {0: "someusername"} does not contain a sequence of keys, it is returned as-is.
To bypass this, remove the single entry array and use it's value directly (as below) or explicitly convert it to an array in your client code.
addNewChat = async (userId, matchedUserId) => {
const user1 = await getUserDataById(userId);
const user2 = await getUserDataById(matchedUserId);
console.log(JSON.stringify('User data: ' + user1));
return admin // don't forget to return the Promise!
.database()
.ref('/chats')
.push({
members: { [userId]: true, [matchedUserId]: true }, // FYI: these are "use value as the key" instructions not arrays.
[userId]: { username: user1.username },
[matchedUserId]: { username: user2.username },
});
};
I want to send a notification to all users who are confirmed guests when the object confirmedGuests is created in the Firebase Realtime Database.
So, I first create an array of all the users from confirmedGuests object. Then, I iterate through all these users and push their deviceTokens to an array of deviceTokens. The array allDeviceTokens is expected to be the array of device tokens of all users in confirmedGuests.
However, when confirmedGuests object is created, the function returns an error.
Below is my cloud function
exports.sendNotification = functions.database
.ref('/feed/{pushId}/confirmedGuests')
.onCreate((snapshot, context) => {
const pushId = context.params.pushId;
if (!pushId) {
return console.log('missing mandatory params for sending push.')
}
let allDeviceTokens = []
let guestIds = []
const payload = {
notification: {
title: 'Your request has been confirmed!',
body: `Tap to open`
},
data: {
taskId: pushId,
notifType: 'OPEN_DETAILS', // To tell the app what kind of notification this is.
}
};
let confGuestsData = snapshot.val();
let confGuestItems = Object.keys(confGuestsData).map(function(key) {
return confGuestsData[key];
});
confGuestItems.map(guest => {
guestIds.push(guest.id)
})
for(let i=0; i<guestIds.length; i++){
let userId = guestIds[i]
admin.database().ref(`/users/${userId}/deviceTokens`).once('value', (tokenSnapshot) => {
let userData = tokenSnapshot.val();
let userItem = Object.keys(userData).map(function(key) {
return userData[key];
});
userItem.map(item => allDeviceTokens.push(item))
})
}
return admin.messaging().sendToDevice(allDeviceTokens, payload);
});
You're loading each user's device tokens from the realtime database with:
admin.database().ref(`/users/${userId}/deviceTokens`).once('value', (tokenSnapshot) => {
This load operation happens asynchronously. This means that by the time the admin.messaging().sendToDevice(allDeviceTokens, payload) calls runs, the tokens haven't been loaded yet.
To fix this you'll need to wait until all tokens have loaded, before calling sendToDevice(). The common approach for this is to use Promise.all()
let promises = [];
for(let i=0; i<guestIds.length; i++){
let userId = guestIds[i]
let promise = admin.database().ref(`/users/${userId}/deviceTokens`).once('value', (tokenSnapshot) => {
let userData = tokenSnapshot.val();
let userItem = Object.keys(userData).map(function(key) {
return userData[key];
});
userItem.map(item => allDeviceTokens.push(item))
return true;
})
promises.push(promise);
}
return Promise.all(promises).then(() => {
return admin.messaging().sendToDevice(allDeviceTokens, payload);
})
I'm using an HTTP-triggered Firebase cloud function to make an HTTP request. I get back an array of results (events from Meetup.com), and I push each result to the Firebase realtime database. But for each result, I also need to make another HTTP request for one additional piece of information (the category of the group hosting the event) to fold into the data I'm pushing to the database for that event. Those nested requests cause the cloud function to crash with an error that I can't make sense of.
const functions = require("firebase-functions");
const admin = require("firebase-admin");
admin.initializeApp();
const request = require('request');
exports.foo = functions.https.onRequest(
(req, res) => {
var ref = admin.database().ref("/foo");
var options = {
url: "https://api.meetup.com/2/open_events?sign=true&photo-host=public&lat=39.747988&lon=-104.994945&page=20&key=****",
json: true
};
return request(
options,
(error, response, body) => {
if (error) {
console.log(JSON.stringify(error));
return res.status(500).end();
}
if ("results" in body) {
for (var i = 0; i < body.results.length; i++) {
var result = body.results[i];
if ("name" in result &&
"description" in result &&
"group" in result &&
"urlname" in result.group
) {
var groupOptions = {
url: "https://api.meetup.com/" + result.group.urlname + "?sign=true&photo-host=public&key=****",
json: true
};
var categoryResult = request(
groupOptions,
(groupError, groupResponse, groupBody) => {
if (groupError) {
console.log(JSON.stringify(error));
return null;
}
if ("category" in groupBody &&
"name" in groupBody.category
) {
return groupBody.category.name;
}
return null;
}
);
if (categoryResult) {
var event = {
name: result.name,
description: result.description,
category: categoryResult
};
ref.push(event);
}
}
}
return res.status(200).send("processed events");
} else {
return res.status(500).end();
}
}
);
}
);
The function crashes, log says:
Error: Reference.push failed: first argument contains a function in property 'foo.category.domain._events.error' with contents = function (err) {
if (functionExecutionFinished) {
logDebug('Ignoring exception from a finished function');
} else {
functionExecutionFinished = true;
logAndSendError(err, res);
}
}
at validateFirebaseData (/user_code/node_modules/firebase-admin/node_modules/#firebase/database/dist/index.node.cjs.js:1436:15)
at /user_code/node_modules/firebase-admin/node_modules/#firebase/database/dist/index.node.cjs.js:1479:13
at Object.forEach (/user_code/node_modules/firebase-admin/node_modules/#firebase/util/dist/index.node.cjs.js:837:13)
at validateFirebaseData (/user_code/node_modules/firebase-admin/node_modules/#firebase/database/dist/index.node.cjs.js:1462:14)
at /user_code/node_modules/firebase-admin/node_modules/#firebase/database/dist/index.node.cjs.js:1479:13
at Object.forEach (/user_code/node_modules/firebase-admin/node_modules/#firebase/util/dist/index.node.cjs.js:837:13)
at validateFirebaseData (/user_code/node_modules/firebase-admin/node_modules/#firebase/database/dist/index.node.cjs.js:1462:14)
at /user_code/node_modules/firebase-admin/node_modules/#firebase/database/dist/index.node.cjs.js:1479:13
at Object.forEach (/user_code/node_modules/firebase-admin/node_modules/#firebase/util/dist/index.node.cjs.js:837:13)
at validateFirebaseData (/user_code/node_modules/firebase-admin/node_modules/#firebase/database/dist/index.node.cjs.js:1462:14)
If I leave out the bit for getting the group category, the rest of the code works fine (just writing the name and description for each event to the database, no nested requests). So what's the right way to do this?
I suspect this issue is due to the callbacks. When you use firebase functions, the exported function should wait on everything to execute or return a promise that resolves once everything completes executing. In this case, the exported function will return before the rest of the execution completes.
Here's a start of something more promise based -
const functions = require("firebase-functions");
const admin = require("firebase-admin");
admin.initializeApp();
const request = require("request-promise-native");
exports.foo = functions.https.onRequest(async (req, res) => {
const ref = admin.database().ref("/foo");
try {
const reqEventOptions = {
url:
"https://api.meetup.com/2/open_events?sign=true&photo-host=public&lat=39.747988&lon=-104.994945&page=20&key=xxxxxx",
json: true
};
const bodyEventRequest = await request(reqEventOptions);
if (!bodyEventRequest.results) {
return res.status(200).end();
}
await Promise.all(
bodyEventRequest.results.map(async result => {
if (
result.name &&
result.description &&
result.group &&
result.group.urlname
) {
const event = {
name: result.name,
description: result.description
};
// get group information
const groupOptions = {
url:
"https://api.meetup.com/" +
result.group.urlname +
"?sign=true&photo-host=public&key=xxxxxx",
json: true
};
const categoryResultResponse = await request(groupOptions);
if (
categoryResultResponse.category &&
categoryResultResponse.category.name
) {
event.category = categoryResultResponse.category.name;
}
// save to the databse
return ref.push(event);
}
})
);
return res.status(200).send("processed events");
} catch (error) {
console.error(error.message);
}
});
A quick overview of the changes -
Use await and async calls to wait for things to complete vs. being triggered in a callback (async and await are generally much easier to read than promises with .then functions as the execution order is the order of the code)
Used request-promise-native which supports promises / await (i.e. the await means wait until the promise returns so we need something that returns a promise)
Used const and let vs. var for variables; this improves the scope of variables
Instead of doing checks like if(is good) { do good things } use a if(isbad) { return some error} do good thin. This makes the code easier to read and prevents lots of nested ifs where you don't know where they end
Use a Promise.all() so retrieving the categories for each event is done in parallel
There are two main changes you should implement in your code:
Since request does not return a promise you need to use an interface wrapper for request, like request-promise in order to correctly chain the different asynchronous events (See Doug's comment to your question)
Since you will then call several times (in parallel) the different endpoints with request-promise you need to use Promise.all() in order to wait all the promises resolve before sending back the response. This is also the case for the different calls to the Firebase push() method.
Therefore, modifying your code along the following lines should work.
I let you modifying it in such a way you get the values of name and description used to construct the event object. The order of the items in the results array is exactly the same than the one of the promises one. So you should be able, knowing that, to get the values of name and description within results.forEach(groupBody => {}) e.g. by saving these values in a global array.
const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();
var rp = require('request-promise');
exports.foo = functions.https.onRequest((req, res) => {
var ref = admin.database().ref('/foo');
var options = {
url:
'https://api.meetup.com/2/open_events?sign=true&photo-host=public&lat=39.747988&lon=-104.994945&page=20&key=****',
json: true
};
rp(options)
.then(body => {
if ('results' in body) {
const promises = [];
for (var i = 0; i < body.results.length; i++) {
var result = body.results[i];
if (
'name' in result &&
'description' in result &&
'group' in result &&
'urlname' in result.group
) {
var groupOptions = {
url:
'https://api.meetup.com/' +
result.group.urlname +
'?sign=true&photo-host=public&key=****',
json: true
};
promises.push(rp(groupOptions));
}
}
return Promise.all(promises);
} else {
throw new Error('err xxxx');
}
})
.then(results => {
const promises = [];
results.forEach(groupBody => {
if ('category' in groupBody && 'name' in groupBody.category) {
var event = {
name: '....',
description: '...',
category: groupBody.category.name
};
promises.push(ref.push(event));
} else {
throw new Error('err xxxx');
}
});
return Promise.all(promises);
})
.then(() => {
res.send('processed events');
})
.catch(error => {
res.status(500).send(error);
});
});
I made some changes and got it working with Node 8. I added this to my package.json:
"engines": {
"node": "8"
}
And this is what the code looks like now, based on R. Wright's answer and some Firebase cloud function sample code.
const functions = require("firebase-functions");
const admin = require("firebase-admin");
admin.initializeApp();
const request = require("request-promise-native");
exports.foo = functions.https.onRequest(
async (req, res) => {
var ref = admin.database().ref("/foo");
var options = {
url: "https://api.meetup.com/2/open_events?sign=true&photo-host=public&lat=39.747988&lon=-104.994945&page=20&key=****",
json: true
};
await request(
options,
async (error, response, body) => {
if (error) {
console.error(JSON.stringify(error));
res.status(500).end();
} else if ("results" in body) {
for (var i = 0; i < body.results.length; i++) {
var result = body.results[i];
if ("name" in result &&
"description" in result &&
"group" in result &&
"urlname" in result.group
) {
var groupOptions = {
url: "https://api.meetup.com/" + result.group.urlname + "?sign=true&photo-host=public&key=****",
json: true
};
var groupBody = await request(groupOptions);
if ("category" in groupBody && "name" in groupBody.category) {
var event = {
name: result.name,
description: result.description,
category: groupBody.category.name
};
await ref.push(event);
}
}
}
res.status(200).send("processed events");
}
}
);
}
);