Similar questions (eg. this) have already been asked and answered in negative. I'd like to if any alternatives exist.
I am developing an application where users can collaboratively edit a document. I don't want to force every user to login. I would like to allow users with a link to be able to edit a document (similar to what Google Docs allows). I was planning to share a token in the link which when presented would grant write access. I would have stored the tokens in a separate collection and matched them. But as per previous answers this is not possible and a security issue.
I don't consider it a security concern (for my purposes). The token is like a pre-shared key. Whoever presents the key is allowed access. If the owner thinks that the key is compromised, he can revoke the same. Kindly help me with a way to achieve this. I'm also curious to know how other apps like Google docs achieve this.
As Mentioned by #Dharmaraj,
In Firebase security rules, you have 3 pieces of information, namely the path, the data and the token. Except from those three you can't pass additional information in a security rule.
Cloud Functions would be a better fit here, given the flexibility. Additionally, with Cloud Functions you'd not be forced to authenticate users, and still be able to connect to Firestore if needed.
I am still new to solo-writing a back-end to my app so I have some concerns,
the concern I am asking about here is a security concern about sharing my database structur in the client app,
As it is known all code that is written on client side is "not safe from interested clients",
I read this medium post by Doug Stevenson from the firebase team,
What I am looking for exactly is an answer to the title of my question (which is the same title as the post on medium):
Should I query my Firebase database directly, or use Cloud Functions?
but I didn't really get an answer as he said that it depends on the situation and requirements of my app,
So can anyone tell me if it is ok,from a security perspective, to do direct queries on the client side that expose the structure of data in my database (firestore), or should I use instead only cloud functions for this?
notes:
I am aware that real-time data can only be achieved using client-sdks and thus I should give up that feature if I don't want to share my database structure in the client app
Allowing direct client access is as safe as you choose to make it.
There's nothing about the structure of data that's not secure. Your implementation lacks security only if users are able to do things that you didn't intend for them to do. That's entirely up to you to implement with security rules. If your rules accurately express what users should and should not be able to do, you will have no problem. If you are unable to use security rules to meet your needs, then you should force access through a backend.
I have been introduced to Firebase a few days ago. Since then I have been trying to discover more features and usage of Firebase, in particular, the usage of the Firestore/Realtime Database.
However, as I am reading into more details, I start to think of some questions. I hope someone that is familiar with Firebase can help me answer them
As for User authentication, I understand that I can use Firebase Authentication where I won't see their real password. However, technically, everything that user stores in my Firestore would be visible to me since I am the owner of the Firebase.
For example, if I were to develop a note/chat app, in which the user can access their notes/chat on the iOS app and also Android. That means all their notes data would be saved in my database. If it happens to contain some private data, then I would be able to read it?
Even if I set security rules, that would be only facing client-side, whereas, for me, the owner of the entire firebase data, I could see the whole thing. Surely, as a customer, you won't want to use an app knowing that I can see everything you write
I am not sure if what I said is true or not. If true, is there a possible solution?
Both of your statements are correct. This happens in most of the apps-websites, the admin or some core developers have full access to the data. That's why privacy policy and GDPR exist. You must specify what data you collect and for what reason. If you intend to use your user data for any other reason you must inform them. Be aware that if you disclose any user information without his permission you can be held liable.
Let's say I'm developing app like Instagram: for iOS, Android and Web. I decided to use Google Firebase as it really seems to simplify the work.
The features user needs in the app are:
Authorization/Registration
Uploading photos
Searching for other people, following them and see their photos
I come from traditional "own-backend" development where I do need to setup a server, create database and finally write the API to let the frontend retrieve the data from the server. That's the reason why it's unclear to me how it all works in Firebase.
So the question is how can I create such app:
Should I create my own API with cloud functions? Or it's ok to work with the database directly from the client-side?
If I work with the database directly why do I need cloud functions? Should I use them?
Sorry for such silly questions, but it is really hard to get from scratch.
The main difference between Firebase and the traditional setup you describe is that with Firebase, as far as the app developer is concerned, the client has direct access to the database, without the need for an intermediate custom API layer. Firebase provides SDKs in various languages that you would typically use to fetch the data you need / commit data updates.
You also have admin SDKs that you can use server-side, but these are meant for you to run some custom business logic - such as analytics, caching in an external service, for exemple - not for you to implement a data fetching API layer.
This has 2 important consequences:
You must define security rules to control who is allowed to read/write at what paths in your database. These security rules are defined at the project level, and rely on the authenticated user (using Firebase Authentication). Typically, if you store the user profile at the path users/$userId, you would define a rule saying that this node can be written to only if the authenticated user has an id of $userId.
You must structure your data in a way that makes it easily readable - without the need for complex database operations such as JOINs that are not supported by Firebase (you do have some limited querying options tough).
These 2 points allow you to skip the 2 main roles of traditional APIs: validating access and fetching/formatting the data.
Cloud functions allow you to react to data changes. Let's say everytime a new user is created, you want to send him a Welcome email: you could define a cloud function sending this email everytime a new node is appended to the users path. They allow you to run the code you would typically run server-side when writes happen, so they can have a very broad range of use-cases: side-effects (such as sending an email), caching data in an external service, caching data within Firebase for easier reads, analytics, etc..
You don't really need a server, you can access the database directly from the client, as long as your users are authenticated and you have defined reasonable security rules on Firebase.
In your use case you could, for example, use cloud functions to create a thumbnail when someone uploads a photo (Firebase Cloud Functions has ImageMagick included for that), or to denormalize your data so your application is faster, or to generate logs. So, basically you can use them whenever you need to do some server side processing when something changes on your database or storage. But I find cloud functions hard to develop and debug, and there are alternatives such as creating a Node application that subscribes to real time changes in your data and processes it. The downside is that you need to host it outside Firebase.
My answer is definitely NOT complete or professional, but here are the reasons why I choose Cloud Functions
Performance
You mentioned that you're writing an instagram-like mobile device app, then I assume that people can comment on others' pictures, as well as view those comments. How would you like to download comments from database and display them on users' devices? I mean, there could be hundreds, maybe thousands of comments on 1 post, you'll need to paginate your results. Why not let the server do all the hard work, free up users' devices and wait for the results? This doesn't seem like a lot better, but let's face it, if your app is incredibly successful, you'll have millions of users, millions of comments that you need to deal with, server will do those hard jobs way better than a mobile phone.
Security
If your project is small, then it's true that you won't worry about performance, but what about security? If you do everything on client side, you're basically allowing every device to connect to your database, meaning that every device can read from/write into your database. Once a malicious user have found out your database url, all he has to do is to
firebase.database().ref(...).remove();
With 1 line of code, you'll lose all your data. Okay, if you say, then I'll just come up with some good security rules like the one below:
This means that for each post, only the owner of that post can make any changes to it or read from it, other people are forbidden to do anything. It's good, but not realistic. People are supposed to be able to comment on the post, that's modifying the post, this rule will not apply to the situation. But again, if you let everybody read/write, it's not safe again. Then, why not just make .read and .write false, like this:
It's 100% safe, because nobody can do anything about anything in your database. Then, you write an API to do all the operations to your database. API limits the operations that can be done to your database. And you have experience in writing APIs, I'm sure you can do something to make your API strong in terms of security, for example, if a user wants to delete a post that he created, in your deletePost API, you're supposed to authenticate the user first. This way, 'nobody' can cause any damage to your database.
It is unclear whether or not to set security rules for database.
Is it enough to just let in just authenticated users? Do I need more complicated things? I have android app, and do all validations and updates inside app.
The video from IO says that there is possibility that someone can get all your data if he knew your app ID. So if user is authenticated and have app ID and somehow build web app he can get data too? I mean if using simple rules.
I`m asking for risks when building just android app and using simple rules (auth is on).
Is it ok for you if any user could edit/create/delete any data in your Firebase database? If this is not ok, you need security rules (you probably need them)
Firebase's security rules are really powerful and easy to use, I suggest you take a look at the documentation.
You need user id or role specific rules, otherwise somebody for example can easily wipe out your all data, or easily manipulate anything.