28 nov. Realtime Database Rules Firebase
We`ll cover more firebase.json options later. First, look at the firebase.json example below and note the database.rules node. It points to a file I called database.rules.bolt where I wrote my bolt rules. If this file was named database.rules.json, Firebase would know that I have my rules in JSON format, but since I named it .bolt, it is automatically routed through the firebase-bolt compiler before sending them to my Firebase in the cloud. Edit the rules again to add read permissions to the profile node, this time restricting access to authenticated users: Firebase database rules control how data stored in a Firebase Realtime Database is backed up, validated, and indexed. These rules are defined using a JSON-like rule expression language that can be configured on a project-by-project basis using the Firebase console or the Firebase CLI. The current database rules for a Firebase project can be viewed in the Firebase console by selecting the project and clicking the Database option in the left navigation pane, and then clicking the Rules tab in the main pane, as shown in Figure 22-1 below: I register the user with Google login and, If it is successfully connected, I save the user`s email address and username in the database. This rule works well: a $ variable can be given any name as long as it is preceded by a $ sign, although a name that uniquely describes the value is recommended. In the case of example $uid, when an application attempts to read a profile entry from the database, the sequence of events goes like this: What if I want to make an if statement in the rules, how? For example, in “MyRequests” the user can write child if his authUid = (Uid saved in “MyFollowers” child) Now suppose that the following database rules have been declared for the project in the Firebase console: Rules can be changed in this screen simply by editing the declarations. After you make the changes, the console displays buttons that allow you to discard or publish the changes so that they become active. It also provides a simulator that can be used to test rules before they are published.
If the rules contain syntax errors, they are reported when you click the Publish button. If the rule has been modified (there is no need to publish rules to test them), click the Run button in the simulator window and notice that the status bar changes to indicate that the read operation has been allowed. Can you help me? I`m newer, so I don`t know deeply about this problem. When I used this: { “rules”: { “.read”: “auth != null”, “.write”: “auth != null” } } It didn`t work. A message appears 401 (Not allowed) It only worked for: { “rules”: { “.read”: true, “.write”: true } } Can I find out if there are rules to allow only one group of children, no more than that, in a child? Consider the following example data structure for a database to store the range and prices of electric and hybrid vehicles: Keep your safety rules simple. Security rules can become too complex and quickly spiral out of control if your data structure isn`t well thought out. This module demonstrates some “best” practices. You`ll probably need to tweak them a bit for your production applications – think carefully about the impact if you deviate from these models. And make sure you`ve read the entire document and all the safety and rule documents before you feel like it. The above example defines a rule that checks the UID in the profiles section of the database. If the auth variable is null (that is, the user has not been authenticated) or if the uid read from the database node to which access is requested does not match the UID of the current user, access is denied. To properly explain how the rule works, we must first understand the concept of the variable $.
2. Firebase receives the request and points to the database rules of the Firebase project associated with the application. When defining the rule described in the previous section, a variable named $uid is used. Variables of this type, called $ variables or collection variables, are used to represent the value assigned to a node location in a requested database path. For example, the path requested in this case might be: These are the default rules that prevent users from reading and writing to your database. These rules allow you to access the database only from the Firebase console. This is any data structure – we could have called these three nodes apples, pears and pineapples. But we`re not crazy, so we called them something descriptive. We then used placeholder paths (see path /userReadable/objectType/uid) to apply rules to groups of object types. Small question, new in the database. All rule attributes must be under one rule or can there be several { “rules”: { with different parameters? In the Firebase database, child nodes can be specified as indexes.
This can be useful for speeding up ordering and querying databases containing large amounts of data. The .indexOn rule type provides a mechanism for you, as the application developer, to inform Firebase of database nodes to index. First of all, the nature of Firebase requires this kind of behavior. When you query a node in Firebase, you get all the child nodes. Firebase is so performance-focused that it could never take the time to evaluate the rules on all child nodes and possibly remove them from the parent node. That would be a huge impact on performance. This chapter explains the basics of implementing database rules using the Firebase console. When a user is authenticated, the authentication authentication variable referenced in the above rules contains the user`s authentication identity. A null value, on the other hand, indicates that the current user is not signed in with one of the Firebase authentication providers. As mentioned earlier, these rules state that only authenticated application users have read and write access to the real-time database data in the project.