I found a neat little example for permission based chat rooms using firebase security api here
Notice the "chat": {
// the list of chats may not be listed (no .read permissions here)
I actually need to list the chats a user belongs to when I load their inbox, however I can't seem to get the .read rule correctly.
Ive tried using the following rule which makes total sense but doesn't work:
"convos": {
".read" : "auth != null && data.child('users').hasChild(auth.id)",
I suspect the problem is that there is still a level between convo and users.. aka would make more sense to do:
"convos": {
".read" : "auth != null && data.child($key + '/users').hasChild(auth.id)",
$key : { ... }
But that's not allowed is complains about $key not existing yet.
How can I allow a user to pull all the convos they belongs to using this setup?
You can't use security rules to filter data. Generally, your data structure will be fairly dependent on your specific use case--most directly on how the data will be read back.
A general solution is to list the chats your user belongs to separate from the bulk chat data, i.e. to heavily denormalize, and access the chats individually.
/messages/$chat_id/... (messages chronologically ordered using push() ids)
/chats/$chat_id/... (meta data)
/my_chats/$user_id/$chat_id/true (the value here is probably not important)
Now to access all of my chats, I could do something like the following:
var fb = new Firebase(URL);
fb.child('my_chats/'+myUserId).on('child_added', function(snap) {
var chatID = snap.name());
loadChat(chatID);
});
function loadChat(chatID) {
fb.child('messages/'+chatID).on('child_added', function(snap) {
console.log('new message', chatID, snap.val());
});
}
You would still want security rules to validate the structure of chat messages, and access to a users' chat list, et al. But the functionality of filtering would be done with an index like this, or by another creative data structure.
I'm not completely sure how you're structuring your Firebase, but this might work:
"convos": {
$key : {
".read" : "auth != null && data.child('users').hasChild(auth.id)",
...
}
Related
I'm trying to implement a Firebase rules read restriction in a data model that has a few nested dynamic child nodes.
I have the following data model:
/groupMessages/<groupId>/<messageId>/
{
"senderId": "<senderId>",
"recipientId": "<recipientId>",
"body": "..."
}
groupId, messageId, senderId and recipientId are dynamic ids. I would like to attach a listener to the /groudId node to listen to new messages. At the same time I only want users to read the message where the senderId or recipientId matches a corresponding auth.token value.
Due to Firebase cascading rules, if I allow the read at the groupId level without restrictions, I can't deny them on the message level.
{
"rules": {
"groupMessages"
"$groupId": {
".read": "auth != null"
}
}
}
}
I also haven't found a way to restrict the read rule on the groupId level to check for sender/recipientId of a message.
Any suggestions greatly appreciated.
As you've found, security rules cannot be used to filter data. But they can be used to restrict what queries can be performed on the data.
For example, you can query for all messages where the current user is the sender with:
var query = ref.child("groupMessages").child(groupId).orderByChild("senderId").equalTo(uid);
And you can secure access to the group's messages to only allow this query with:
{
"rules": {
"groupMessages": {
"$groupId": {
".read": "auth.uid != null &&
query.orderByChild == 'senderId' &&
query.equalTo == auth.uid"
}
}
}
}
The query and rules now exactly match, so the security rules will allow the query, while they'd reject a broader read operation. For more on this, see query based rules in the Firebase documentation
You'll note that this only works for a single field. Firebase Database queries can only filter on a single field. While there are workarounds by combining multiple values into a single property, I don't think those apply to your scenario, since they only work for AND queries, where you seem to want an OR.
You also seem to want to query on /groupMessages instead of on messages for a specific group. That also isn't possible: Firebase Database orders/filters on a property that is at a fixed path under each child of the node where you run the query. You cannot query across two dynamic levels, as you seem to be trying. For more on this see: Firebase Query Double Nested and Firebase query if child of child contains a value.
The common solution for your problem is to create a list of IDs for each user, which contains just the IDs of all messages (and/or the groups) they have access to.
userGroups: {
uid1: {
groupId1: true,
groupId2: true
},
uid2: {
groupId2: true,
groupId3: true
}
}
With this additional data structure (which you can much more easily secure), each user can simply read the groups they have access to, and your code then reads/queries the messages in each group. If necessary you can add a similar structure for the messages themselves too.
Finally: this type of recursive loading is not nearly as inefficient as many developers initially think, since Firebase pipelines the requests over an existing connection.
I am stuck trying to allow an an array of admins access to their data.
I have a database structure like this:
{
"Respondents": {
"Acme Corp": {
"admins": ["mMK7eTrRL4UgVDh284HntNRETmx1", ""mx1TERNmMK7eTrRL4UgVDh284Hnt"],
"data": {data goes here...}
},
"Another Inc": {
"admins": ["Dh284HmMK7eTrRL4UgVDh284HntN", ""x1TERNmx1TERNmMK7eTrRL4UgVDh"],
"data": {their data goes here...}
}
}
}
And then I tried to set my rules like this
{
"rules": {
"Respondents": {
"$organisation" : {
".read": "root.child('Respondents').child($organisation).child('admins').val().includes(auth.id)",
".read": "root.child('Respondents').child($organisation).child('admins').val().includes(auth.id)"
}
}
}
}
..but that won't parse in the Firebase Database Rules editor
I get "Error saving rules - Line 7: No such method/property 'includes'", but I need something to match the user id with the array of admins.
Any experience or suggestions?
As you've found, there is no includes() operation in Firebase's security rules. This is because Firebase doesn't actually store the data as an array. If you look in the Firebase Database console or read this blog post you will see that Firebase stores it as a regular object:
"admins": {
"0": "mMK7eTrRL4UgVDh284HntNRETmx1",
"1": "mx1TERNmMK7eTrRL4UgVDh284Hnt"
}
And since that is a regular JavaScript object, there is no contains() method on it.
In general creating arrays are an anti-pattern in the Firebase Database. They're often the wrong data structure and when used are regularly the main cause of scalability problems.
In this case: you're not really looking to store a sequence of UIDs. In fact: the order of the UIDs doesn't matter, and each UID can be meaningfully present in the collection at most once. So instead of an array, you're looking to store set of uids.
To implement a set in Firebase, you use this structure:
"admins": {
"mMK7eTrRL4UgVDh284HntNRETmx1": true,
"mx1TERNmMK7eTrRL4UgVDh284Hnt": true
}
The value doesn't matter much. But since you must have a value to store a key, it is idiomatic to use true.
Now you can test whether a key with the relevant UID exists under admins (instead of checking whether it contains a value):
"root.child('Respondents').child($organisation).child('admins').child(auth.uid).exists()",
In my Firebase database I have a node eventdata contains a list of data elements related to a certain event.
Each event item has an event_log node where all the logging of that certain event is done.
The goal is to allow users only access to part of the event_log items. (e.g. the items they created themselves)
When the respective part in the Security Rules looks like this, everything works fine, but no access control on individual items is possible.
"eventdata":{
"$event":{
"event_log":{
".read": " auth != null",
".write":" auth != null"
}
}
}
Changing the code such that it uses another $ variable (but still should allow access from all authenticated users) results in not being able to access the event_log.
"eventdata":{
"$event":{
"event_log":{
"$logitem":{
".read": " auth != null",
".write":" auth != null"
}
}
}
}
Isn't it possible to 'nest' $ variables in the Security API? I couldn't find an answer to this in the Firebase Docs. Is there any other solution other than having to restructure my code?
Thanks in advance
I have these requirements:
User will log in via email and multiple Oauth providers. I use function like User.findByEmail('1#1.com'). So I need to have permision to see the list of users before being authenticated.
User's email address, geolocation and age should be kept secretly from other users.
My first plan was:
users:{
$user-id:{
// public
".read" : true,
name,
created_at,
private: {
".read" : "auth.email === data.child('email').val()",
age,
email,
geolocation,
}
$piority = email
}
}
Then I realized no, it just doesn't work that way. So would anyone please tell me how to do it correctly? Thanks in advance.
P.S. Firebase really needs a filter/serialize method.
There are really several questions in this post. The first is how to store private data. One simple change you can make is to invert the public/private and user keys--they don't have to be nested in the same user record.
/users/$user_id/...public data...
/private/$user_id/...private data...
This makes securing the data quite a bit simpler.
Another question is regarding duplicate email detection. If we assume you are using simple login here, this is all pretty moot. You can check to see if an email address exists by simply trying to create the account. An error will be returned if the email is already registered.
If that doesn't solve it, you can still check this manually, without providing a list of users' emails. This is typically done with an index. When a new account is created, write something like this:
/email_index/$escaped_email/$userid ($userid is the value)
Now when you want to check if the email is available, you do a read like this:
var ref = new Firebase(URL);
function checkEmail(emailAddress, callback) {
ref.child('email_index/'+escapeEmail(emailAddress)).once('value', function(snap) {
callback(snap.val() !== null);
});
}
function escapeEmail(emailAddress) {
return (email || '').replace('.', ',');
}
checkEmail(EMAIL_ADDRESS, function(exists) {
console.log(EMAIL_ADDRESS + (exists? 'does' : 'does not') + ' exist!');
});
To prevent someone from listing the emails, you do something like this in your (amazingly flexible and really quite sophisticated, even for enterprise apps) security rules:
"email_index": {
// no .read rule here means that the data cannot be listed; I have to know the email address to check it
"$email_address": {
".read": true,
// it can only be claimed once and the value must be my user id
".write": "auth.uid === newData.val() && !data.exists()"
}
}
I'm trying to make new post objects readable only by users that exist in the 'members' dictionary stored in each post. I keep getting "7:17: Invalid == expression: left operand is not a number, boolean, string, or null." on the .read rule:
{
"rules": {
"posts" : {
".write":true,
"$post" : {
".read": "data.child('members').child(auth.uid) == true"
}
}
}
}
I pass the 'uid' parameter in the token I generate per: https://www.firebase.com/docs/security/custom-login.html
The purpose is to only allow posts to be read by users that exist in its member array. I can't find any examples about accessing nested data in the firebase documentation, google groups, or google searches :-(
Is this allowed/possible?
You need to add .val() after .child() in order to get the value out. :-) Try:
".read": "data.child('members').child(auth.uid).val() == true"