Skip to main content

Writing Effective Policies

Defining Paths with Dynamic Segments​

Use dynamic segments (prefixed with $) to create flexible and reusable policies that apply to multiple documents or collections.

Example:​

{
  "users/$userId": { ... },
  "posts/$postId/comments/$commentId": { ... }
}

In this example, $userId, $postId, and $commentId are placeholders that match any value at that position in the path.

Rules: Controlling Access​

Rules determine whether a read or write operation is permitted based on specified conditions.

  • Read Rule ("read"): Must evaluate to true for a read operation to succeed
  • Create Rule ("create"): Specific rule for document creation
  • Update Rule ("update"): Specific rule for document updates
  • Delete Rule ("delete"): Specific rule for document deletion

Special Variables Available in rules and hooks:​

  • @user.address: The wallet address of the user making the request
  • @data: The current state of the document before the write operation
  • @newData: The proposed state of the document after the write operation
  • get(path): Get data at a specific path
  • getAfter(path): Get data at a specific path after all pending changes in the batch are applied
  • @time.now: The current server time, if off-chain, this use's Tarobase's server time, and if on-chain it uses the timestamp of the last confirmed block.

Operators:​

Logical Operators:

  • && (and)
  • || (or)
  • ! (not)

Comparison Operators:

  • ==, !=
  • <, >
  • <=, >=

Null Checks:

  • variable != null
  • variable == null

Example Rule:​

"create": "@newData.admin == @user.address"

This rule allows a create operation only if the admin field in the new state matches the user's wallet address.

Fields: Enforcing Data Structure​

When storing data on-chain, you must define the fields and their data types explicitly.

Supported Data Types:​

  • String
  • Address
  • Int
  • UInt
  • Bool

Add ? after the type to make it optional, e.g., "UInt?".

Example Fields Definition:​

"fields": {
  "createdBy": "Address",
  "text": "String",
  "amount": "UInt",
  "maxMembers": "UInt?"
}