Initially I had this code:
const newUserObject = { name: "username", uid: "FirebaseUID", posts: [] }
await Promise.all([
admin.firestore().collection("users").doc("FirebaseUID").set(newUserObject),
mongoDb.collection("users").insertOne(newUserObject)
])
For some reason, this doesn't work and returns the error "cannot encode value". Here is the complete stack trace:
Cannot encode value: 60bb87e2cb98774f01d8bb0b
at Serializer.encodeValue (~/node_modules/#google-cloud/firestore/build/src/serializer.js:168:15)
at Serializer.encodeFields (~/node_modules/#google-cloud/firestore/build/src/serializer.js:57:30)
at Function.fromObject (~/node_modules/#google-cloud/firestore/build/src/document.js:99:53)
at Object.op (~/node_modules/#google-cloud/firestore/build/src/write-batch.js:267:58)
at ~/node_modules/#google-cloud/firestore/build/src/write-batch.js:457:44
at Array.map (<anonymous>)
at WriteBatch._commit (~/node_modules/#google-cloud/firestore/build/src/write-batch.js:457:31)
at processTicksAndRejections (internal/process/task_queues.js:95:5)
at async Promise.all (index 0)
Caused by: Error
at WriteBatch.commit (~/node_modules/#google-cloud/firestore/build/src/write-batch.js:426:23)
at DocumentReference.set (~/node_modules/#google-cloud/firestore/build/src/reference.js:343:14)
at ~/dist/handlers/users.js:75:68
at Generator.next (<anonymous>)
at fulfilled (~/dist/handlers/users.js:5:58)
at processTicksAndRejections (internal/process/task_queues.js:95:5)
The value looks similar to MongoDB ObjectID but I am sure I am not passing that in Firestore object in any way. I checked an answer to a similar question which said you cannot set empty arrays in a new document but that doesn't seem right to me.
If I rewrite my code as follows, it works like charm.
await admin.firestore().collection("users").doc("FirebaseUID").set(newUserObject)
await mongoDb.collection("users").insertOne(newUserObject)
To confirm, nothing is undefined in the object I am trying to set. The issue occurs only when I use it with MongoDB's insertOne in a Promise.all().
Steps to clone the issue:
npm init -y
npm i firebase-admin mongodb
Then copy this code:
const admin = require("firebase-admin")
const mongo = require("mongodb")
const client = mongo.MongoClient("mongodb://localhost:27017/dbname", {
useNewUrlParser: true,
useUnifiedTopology: true,
auth: {
user: "mongodbusername",
password: "mongodbpassword"
}
})
client.connect().then(async () => {
console.log("MongoClient Connected");
admin.initializeApp({
credential: admin.credential.cert("serviceAccountKey.json"),
databaseURL: "https://<project-id>.firebaseio.com"
})
const newUserObject = {name: "NewUser", uid: "userUID", posts: ["PostID1"]}
// UPDATING INDIVIDUALLY
// await admin.firestore().collection("users").doc(newUserObject.uid).set(newUserObject)
// await client.db("lasergg").collection("users").insertOne(newUserObject)
// Works perfectly
// UPDATING IN A PROMISE.ALL()
await Promise.all([
admin.firestore().collection("users").doc(newUserObject.uid).set(newUserObject),
client.db("local").collection("users").insertOne(newUserObject)
])
// Throws error Error: Cannot encode value: 60bdee0a77659f27d493dec8
console.log("All Documents Added!");
})
I modified the source code of Firestore Node SDK here and logged the 'val' parameter [console.log(val, typeof val)] that encodeValue function takes and the output was:
60be04dd53e7965bf4a23173 object
Edit: I logged values being passed in encodeValue() when running promises individually and the output is:
I ran the same when running in Promise.all():
This is what I edited in 'serialier.js':
Fix
You should be able to fix this problem by passing a copy of newUserObject into MongoDB, like this:
await Promise.all([
admin.firestore().collection("users").doc("FirebaseUID").set(newUserObject),
mongoDb.collection("users").insertOne({ ...newUserObject })
])
Note this: insertOne({ ...newUserObject }).
Explanation
When you try to insert a document into MongoDB without an _id field, MongoDB creates one automatically by generating an ObjectId. The operation basically looks like this: newUserObject._id = new ObjectId().
It seems that when you run firestore.set() and mongo.insertOne() in parallel, this happens before the serializer step in Firestore.
So whenever the serializer starts encoding, it sees this new _id field and tries to encode it, and that's where it fails. Note that it sees the _id field because you are passing the same object reference (newUserObject) to both firestore.set() and mongo.insertOne().
This explains why executing the operations sequentially works. Here you first insert the document into Firestore and only then into MongoDB, so the _id field is no longer a problem:
await admin.firestore().collection("users").doc("FirebaseUID").set(newUserObject)
await mongoDb.collection("users").insertOne(newUserObject)
However, if you were to reverse the order here and inserted into MongoDB first, you'd encounter the same problem.
I just graduated from a Full Stack Bootcamp and this is my first post. I am still trying to learn and apply all of this stuff. Working on a portfolio project for a server using NodeJs/MongoDB/Mongoose and am trying to figure out how to intercept the .catch error and generate my own error message. I'm making a PUT request using an object ID for a specific record and everything is working when a valid ID is passed. However, if I test using an invalid ID it goes straight to catch error and bypasses my handling of this type of scenario. Here is the code I'm trying to manipulate:
.put((req, res, next) => {
Guitar.findByIdAndUpdate(req.params.guitarId, {$set: req.body}, { new: true })
.then(guitar => {
if (guitar) {
console.log(guitar);
res.statusCode = 200;
res.setHeader('Content-Type', 'application/json');
res.json(guitar);
} else {
res.statusCode = 403;
res.setHeader('Content-Type', 'text/plain');
res.end(`${req.params.guitarId} does not match any guitars in database`);
}
})
.catch(err => next(err));
})
I assumed that if I tried to pass an invalid ID then if(guitar) would return false, then return my error code. But instead it appears that if an invalid ID is sent then it never gets to that point, instead giving the "Cast to Object Id" failure outside of my if/else code. Am I approaching this incorrectly? Thanks in advance for any insight!!!
The Cast to ObjectId failed is occurring before the find operation is sent to the server, so there is never a chance for the promise to resolve and move on to the .then.
You might try explicitly casting the value to ObjectId inside a try-catch block to handle that specific issue, or add some to the .catch for that error.
Could some one help me out on below question please :-)
I'm making a post call through redux action, which is below.
export const addEmployee = ({ firstName, surname, contactNumber, email }) => async dispatch => {
const payloadBody = JSON.stringify({ firstName, surname, contactNumber, email });
fetch('/api/users', {
method: 'POST',
body: payloadBody,
headers: {
'Content-Type': 'application/json'
}
})
.then(response => {
if (!response.ok) {
return response.text()
.then(text => {
throw Error(text)
});
} else {
dispatch(setAlert("New Employee added ", 'danger'));
}
})
.catch(error => {
console.log('>>> in CATCH block, error is =>', error);
console.log('>>> in CATCH block, error name is =>', error.name);
console.log('>>> in CATCH block, error message is =>', error.message);
let allKeys = Object.getOwnPropertyNames(error);
console.log(allKeys);
// const errors = [];
// Object.keys(error.message).forEach(key => {
// console.log('>>> key are ', key)
// })
// const keys = Object.keys(error.message);
// console.log(keys);
// const errors = error.message['errors'];
// const errors = error.response.data.errors;
// if (errors) {
// errors.forEach(error => dispatch(setAlert(error.msg, 'danger')));
// }
dispatch({
type: REGISTER_FAIL
});
})
}
Above post call on failure, returns body with error message, an example is below
{
"errors": [
{
"msg": "User already exist with email"
}
]
}
Question
What I'm trying to achieve is, to grab the errors[] and pass the error message through to a component, the trouble I have is accessing the error[] array within the returned array message. I'll describe below what I've attempted, it also can be seen in the redux action method I posted above.
Try-1
console.log('>>> in CATCH block, error is =>', error); yields just Error
Try-2
console.log('>>> in CATCH block, error name is =>', error.name); yields {"errors":[{"msg":"User already exist with email"}]} and the typeof this is string since I'm returning text() return response.text().then(text => { throw Error(text) })
Try-3
When I return as json() return response.json().then(text => { throw Error(text) })and console.log('>>> in CATCH block, error message is =>', error.message); yields object.
The questions again What I'm trying to achieve is, to grab the errors[] and pass the error message through to a component such as below
const errors = error.message; // this is where I'd like to extract the error.
if (errors) {
errors.forEach(error => dispatch(setAlert(error.msg, 'danger')));
}
Hope the above description is clear, please let me know if you require more info,
I know I'm missing some crucial knowledge of working with error objects, could someone please shed some light on this please :-)
Pattern for throwing errors recovered from standard-format HTTP payload
Your redux action does work over HTTP. Sometimes the server responds with bad news, and it seems like there's a standardized format the server uses to report that news. Also, sometimes your own code throws. You want to handle both kinds of problem with control structures related to Errors.
Basic pattern for an async Redux action
Before we start: your action is marked async, but you're still chaining .then and .catch. Let's switch to async/await, converting this:
export const addEmployee = (/*...*/) = async ( dispatch, getState ) => {
fetch(/* ... */)
.then(response => {
return response.text()
.then(text => {
// happy-path logic
throw Error(text)
})
})
.catch(error => {
// sad-path logic
dispatch(/* ... */)
})
}
...into this:
export const addEmployee = (/*...*/) = async ( dispatch, getState ) => {
try {
let response = await fetch(/* ... */)
let responseText = await response.text()
// happy-path logic
dispatch(/* ... */)
return // a redux action should return something meaningful
} catch ( error ) {
// sad-path logic
dispatch(/* ... */)
return // a failed redux action should also return something meaningful
}
}
Now let's talk about errors.
Error basics
Meet throw:
try { throw 'mud' } catch( exception ) { /* exception === 'mud' */ }
try { throw 5 } catch( exception ) { /* exception === 5 */ }
try { throw new Date() } catch( exception ) { /* exception is a Date */ }
You can throw just about anything. When you do, execution halts and immediately jumps to the closest catch, searching all the way through the stack until it finds one or runs out of stack. Wherever it lands, the value you provided to throw becomes the argument received by catch (known as an "exception"). If nothing catches it, your JS console logs it as an "uncaught exception."
You can throw anything, but what should you throw? I think you should only throw instances of Error, or one of its subclasses. The two main reasons are that the Error class does some helpful things (like capturing a stacktrace), and because one of your two sources of failure is already going to be throwing Error instances, so you must do something similar if you wish to handle both with a single codepath.
Meet Error:
try {
throw new Error('bad news')
} catch ( error ) {
console.log(error.message)
//> 'bad news'
}
We already know that an Error will be thrown if code within your action blows up, e.g. JSON.parse fails on the response body, So we don't have to do anything special to direct execution onto the catch path in those scenarios.
The only thing we have to be responsible for is to check whether the HTTP response contains something that looks like your server's "standard error payload" (more on that later), which your sample suggests is this:
{
"errors": [
{
"msg": "ERROR CONTENT HERE"
}
]
}
Here's the core issue
This handling has to be special because no javascript engine considers it an error simply to receive an HTTP payload that can be parsed as JSON and which contains a key named "errors". (Nor should they.) This payload pattern is merely a custom convention used by some or all of the HTTP endpoints that you talk to.
That's not to say it's a bad idea. (I think it's great!) But that explains why it must be done custom: because this pattern is just your private little thing, and not actually special in a way that would make browsers treat it the special way you want.
So here's our plan:
make the request, relying on try/catch to capture things thrown by our tools
if we get a response that seems bad:
examine the payload for an error encoded in the "standard format"; I call anything like this an "API error"
if we find an API error, we will create and throw our own Error, using the API error content as its message
if we don't find an API error, we'll treat the raw body text of the response as the error message
if we get a response that seems good:
dispatch the good news (and useful data) to the store
Here's what that looks like in code:
export const addEmployee = ({
firstName,
surname,
contactNumber,
email
}) => async ( dispatch, getState ) => {
const payloadBody = {
firstName,
surname,
contactNumber,
email
}
try {
// step 1
let response = await fetch('/api/users', {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify(payloadBody)
})
let responseText = await response.text()
if (!response.ok) {
// step 2
let errorString = getErrorMessageFromResponseBody(responseText)
throw new Error(errorString) // API errors get thrown here
}
// step 3
let responseJson = JSON.parse(responseText)
dispatch(setAlert('New Employee added', responseJson.user.name))
/*
A redux action should always returns something useful.
addEmployee might return the `user` object that was created.
*/
return responseJson.user
} catch ( error ) {
// all errors land here
dispatch({
type: REGISTER_FAIL,
message: error.message
})
/*
A failed redux action should always return something useful (unless you prefer to throw).
For now, we'll return the reason for the failure.
*/
return error.message
}
}
function getErrorMessageFromResponseBody( string ) {
let errorString = string
try {
let json = JSON.parse(string)
if(json.errors) {
errorString = json.errors[0].msg
}
} catch ( parseOrAccessError ) {}
return errorString
}
Here's what can be thrown to that catch block:
anything thrown by JSON.parse when applied to the arguments
anything thrown by fetch
if !response.ok, the whole response payload (or just an error message if the payload contains an API error)
Exception handling
How can you tell those different kinds of failure apart? Two ways:
Some failures throw specific subclasses of Error, which you can test for with error instanceof SomeErrorClass:
JSON.stringify throws a TypeError if it can't serialize its argument (if you have custom .toJSON anywhere, it can also throw anything that throws)
fetch throws a TypeError if it can't reach the internet
JSON.parse throws a SyntaxError if the string can't be parsed (if you use a custom reviver, those errors get thrown too)
Any instance of Error or its subclasses will have a .message; you can test that string for specific cases
How should you handle them?
If JSON.stringify blows up, it's because you wired your data wrong. In that case, you probably want to do something that will alert the developer that something is broken and help diagnose the issue:
console.error(error)
dispatch some failure action that includes the error.message
show a generic error message on-screen
If fetch throws, you could dispatch a failure that presents a "fix your wifi" warning to the user.
If JSON.parse throws, the server is melting down, and you should show a generic error message.
A little sophistication
Those are the basic mechanics, but now you confront a messy situation. Let's list some challenges:
You may have already noticed one problem: "no internet" will present the same way as "circular data": a thrown TypeError.
It turns out that the precise text of JSON.stringify errors depends on the actual value supplied to that function, so you can't do something like error.message === CONSTANT_STRINGIFY_ERROR_MESSAGE.
You may not have an exhaustive list of every msg value the server can send in an API error.
So how are you supposed to tell the difference between a problem reported by a sane server vs a client-side bug vs a broken server vs unusable user data?
First, I recommend creating a special class for API errors. This lets us detect server-reported problems in a reliable way. And it provides a decent place for the logic inside getErrorMessageFromResponseBody.
class APIError extends Error {}
APIError.fromResponseText = function ( responseText ) {
// TODO: paste entire impl of getErrorMessageFromResponseBody
let message = getErrorMessageFromResponseBody(responseText)
return new APIError(message)
}
Then, we can do:
// throwing
if (!response.ok) {
// step 2
throw APIError.fromResponseText(responseText)
}
// detecting
catch ( exception ) {
if(exception instanceof APIError) {
switch(APIError.message) {
case 'User already exist with email':
// special logic
break
case 'etc':
// ...
}
}
}
Second, when throwing your own errors, never provide a dynamic string as the message.
Error messages for sane people
Consider:
function add( x, y ) {
if(typeof x !== 'number')
throw new Error(x + ' is not a number')
if(typeof y !== 'number')
throw new Error(y + ' is not a number')
return x + y
}
Every time add is called with a different non-numeric x, the error.message will be different:
add('a', 1)
//> 'a is not a number'
add({ species: 'dog', name: 'Fido' }, 1)
//> '[object Object] is not a number'
The problem in both cases is that I've provided an unacceptable value for x, but the messages are different. That makes it unnecessarily hard to group those cases together at runtime. My example even makes it impossible to tell whether it's x or y that offends!
These troubles apply pretty generally to the errors you'll receive from native and library code. My advice is to not repeat them in your own code if you can avoid it.
The simplest remedy I've found is just to always use static strings for error messages, and put some thought into establishing conventions for yourself. Here's what I do.
There are generally two kinds of errors:
some value I wish to use is objectionable
some operation I attempted has failed
In the first case, the relevant info is:
which datapoint is bad; I call this the "topic"
why it is bad, in one word; I call this the "objection"
All error messages related to objectionable values ought to include both datapoints, and in a manner that is consistent enough to facilitate flow-control while remaining understandable by a human. And ideally you should be able to grep the codebase for the literal message to find every place that can throw the error (this helps enormously with maintenance).
Here is how I construct the messages:
[objection] [topic]
There is usually a discrete set of objections:
missing: value was not supplied
unknown: could not find value in DB & other "bad key" issues
unavailable: value is already taken (e.g. username)
forbidden: sometimes specific values are off-limits despite being otherwise fine (e.g. no user may have username "root")
invalid: heavily overused by dev community; treat as option of last resort; reserved exclusively for values that are of the wrong datatype or syntactically unacceptable (e.g. zipCode = '__!!#')
I supplement individual apps with more specialized objections as needed, but this set comes up in just about everything.
The topic is almost always the literal variable name as it appears within the code block that threw. To assist with debugging, I think it is very important not to transform the variable name in any way.
This system yields error messages like these:
'missing lastName'
'unknown userId'
'unavailable player_color'
'forbidden emailAddress'
'invalid x'
In the second case, for failed operations, there's usually just one datapoint: the name of the operation (plus the fact that it failed). I use this format:
[operation] failed
As a rule, operation is the routine exactly as invoked:
try {
await API.updateUserProfile(newData)
} catch( error ) {
// can fail if service is down
if(error instanceof TypeError)
throw new Error('API.updateUserProfile failed')
}
This isn't the only way to keep your errors straight, but this set of conventions does make it easy to write new error code without having to think very hard, react intelligently to exceptions, and locate the sources of most errors that can be thrown.
Handling server inconsistencies
A final topic: it's pretty common for a server to be inconsistent about how it structures its payloads, particularly with errors but also with successes.
Very often, two endpoints will encode their errors using slightly different envelopes. Sometimes a single endpoint will use different envelopes for different failure cases. This is not usually deliberate, but it is often a reality.
You should coerce all the different flavors of server complaint into a single interface before any of this madness can leak into the rest of your application, and the shore of the client/server boundary is the best place to immediatley jettison server weirdness. If you let that stuff escape into the rest of your app, not only will it drive you insane, but it will make you brittle by allowing the server to surface errors deep inside your app, far away from the real source: a violated API contract.
A way to support a variety of envelopes is by adding extra code to getErrorMessageFromResponseBody for each of the different envelopes:
function getErrorMessageFromResponseBody( string ) {
let errorString = string
/*
"Format A"
{ errors: [{ msg: 'MESSAGE' }] }
used by most endpoints
*/
try { /*... */ } catch ( parseOrAccessError ) {}
/*
"Format B"
{ error: { message: 'MESSAGE' } }
used by legacy TPS endpoint
*/
try { /*... */ } catch ( parseOrAccessError ) {}
/*
"Format C"
{ e: CODE }
used by bandwidth-limited vendor X
use lookup table to convert CODE to a readable string
*/
try { /*... */ } catch ( parseOrAccessError ) {}
return errorString
}
One of the values of having a dedicated APIError class to wrap these things is that the class constructor provides a natural way to gather all this up.
I'm having an issue with a Firestore observer and it's associated rules. I'm trying to have rules that only allow the user to see invites that contain the user's email address. However, if I delete a document from the collection, the snapshot observer throws an error Uncaught Error in onSnapshot: FirebaseError: Null value error. for 'get' # L92.
Here's my rules:
match /invites/{inviteID} {
function isSignedIn() {
return request.auth != null;
}
function isUserInvite() {
return request.auth.token.email != null &&
request.auth.token.email == resource.data.user_email;
}
allow read: if isSignedIn() && isUserInvite();
allow write: if true;
}
And here's my listener.
firebase.firestore()
.collection("invites")
.where(`user_email`, '==', myUserEmail) // this would be the users email
.onSnapshot((snapshot) => {
snapshot.forEach( doc => {
console.log(doc.id, doc.data())
})
})
It works for observing new documents, but fails when deleting a document. The following code makes the observer throw an error.
// creates a new invite and the snapshot listener informs me
await firebase.firestore()
.collection('invites')
.doc("invite_1")
.set({
user_email: someUserEmail, // use the users email here
date_added: firebase.firestore.FieldValue.serverTimestamp()
})
// deletes the invite, but the snapshot throws an error
await firebase.firestore()
.doc(`invites/invite_1`)
.delete()
UPDATE
I've found that this is only happening in the firestore emulator and not in production. Both the emulator and production have the same rules.
After submitting a bug report to Google - they confirmed it was a bug that only applied to the emulator. This was fixed in a new release. Here’s a link to the GitHub issue for any needed reference.
https://github.com/firebase/firebase-tools/issues/2197
The following message is returned to me: E11000 duplicate key error collection ..., when one of the attributes that is specified as unique: true, it would be possible to modify this error message with a custom one for example:
{error: '11000', field: 'name of the field giving the problem'}
Uniqueness in mongoose is not a validation parameter, so you can't create custom error message for these fields, it is only to create uniqueness index in DB.
What you can do is, create a Error Handling middleware in Mongoose, and intercept 11000 errors, and send a custom error message in response.
From Mongoose documentation
// Handler **must** take 3 parameters: the error that occurred, the document
// in question, and the `next()` function
schema.post('save', function(error, doc, next) {
if (error.name === 'MongoError' && error.code === 11000) {
next(new Error('There was a duplicate key error'));
} else {
next();
}
});
Note: This allows you to catch 11000 duplication key error, but it doesn't tell you which field caused thee problem.