firebase-rules-describe

Generate complex database.rules.json files with ease. With this package you can describe your Firebase rules in your native language and split the definitions in multiple files.

Basic usage

Install globally with npm install firebase-rules-describe -g

Create a file containing the definitions of your rules: database.definitions.json

{
  "rules": {
    "example": {
      ".read": "{Authenticated User}",
      ".write": "{User is Admin}",
      ".validate": "{Hello World}"
    }
  }
}

Create a file containing the specs for the definitions: database.specs.json

{
  "Authenticated User": "auth !== null",
  "User is Admin": "root.child('admins/' + auth.uid).val() === true",
  "Hello World": "newData.val() === 'Hello World'"
}

Run the following command to process these files into an output file:

firebase-rules-describe process database.definitions.json database.specs.json database.rules.json

These filenames are the defaults, so you can ommit them:

firebase-rules-describe process

Output will be a file: database.rules.json

{
  "rules": {
    "example": {
      ".read": "auth !== null",
      ".write": "root.child('admins/' + auth.uid).val() === true",
      ".validate": "newData.val() === 'Hello World'"
    }
  }
}

Features

Comments

Both in the definitions and spec files, you can include comments. These will not be included in the rules output file.

Definitions within Specs

You can create more complex Specs by including definitions in the Specs. For example consider the following Spec file:

{
  // Authentication
  "Admin": "root.child('admins/' + auth.uid).val() === true",
  
  // Posts
  "Post creator": "root.child('posts/' + $post_id + '/creator').val() === auth.uid",
  "Global editor": "auth.uid === 'global-editor'",
  "Post editor": "{Admin} || {Post creator} || {Global editor}"
}

This allows you to specify in your rules definitions, that any {Post editor} can write to a post. This includes the post creator, the admin and a global editor. Note that the $post_id wildcard variable is used in the spec in order to determine the post creator.

{
  "rules": {
    "posts": {
      // Rules for every Post
      "$post_id": {
        ".write": "{Post editor}"
      }
    }
  }
}

Split files

Your rules definitions file can be split in different files. Use [filename.json] to include a file at that location. Use the key at that location as the root key in the new file.

database.definitions.json

{
  "rules": {
    "posts": "[posts.json]",
    "users": "[users.json]"
  }
}

posts.json

{
  "posts": {
    "$post_id": {
      // Post rules
    }
  }
}

users.json

{
  "users": {
    "$user_id": {
      // User rules
    }
  }
}