bknd-assign-permissions

Assign Permissions

Configure detailed permissions for roles using simple strings, extended format with effects, and conditional policies.

Prerequisites

• Bknd project with code-first configuration
• Auth enabled (auth: { enabled: true })
• Guard enabled (guard: { enabled: true })
• At least one role defined (see bknd-create-role)

When to Use UI Mode

• Viewing current role permissions
• Quick permission checks

UI steps: Admin Panel > Auth > Roles > Select role

Note: Permission assignment requires code mode. UI is read-only.

When to Use Code Mode

• Assigning permissions to roles
• Adding permission effects (allow/deny)
• Creating conditional policies
• Entity-specific permission rules

Code Approach

Step 1: Simple Permission Strings

Assign basic permissions as string array:

import { serve } from "bknd/adapter/bun";
import { em, entity, text } from "bknd";

const schema = em({
  posts: entity("posts", { title: text().required() }),
});

serve({
  connection: { url: "file:data.db" },
  config: {
    data: schema.toJSON(),
    auth: {
      enabled: true,
      guard: { enabled: true },
      roles: {
        editor: {
          implicit_allow: false,
          permissions: [
            "data.entity.read",    // Read any entity
            "data.entity.create",  // Create in any entity
            "data.entity.update",  // Update any entity
            // No delete permission
          ],
        },
      },
    },
  },
});

Available Permissions

Permission	Filterable	Description
data.entity.read	Yes	Read entity records
data.entity.create	Yes	Create new records
data.entity.update	Yes	Update existing records
data.entity.delete	Yes	Delete records
data.database.sync	No	Sync database schema
data.raw.query	No	Execute raw SELECT
data.raw.mutate	No	Execute raw INSERT/UPDATE/DELETE

Filterable means you can add conditions/filters via policies.

Step 2: Extended Permission Format

Use objects for explicit allow/deny effects:

{
  roles: {
    moderator: {
      implicit_allow: false,
      permissions: [
        { permission: "data.entity.read", effect: "allow" },
        { permission: "data.entity.update", effect: "allow" },
        { permission: "data.entity.delete", effect: "deny" },  // Explicit deny
      ],
    },
  },
}

Permission Effects

Effect	Description
allow	Grant the permission (default)
deny	Explicitly block the permission

Deny overrides allow - useful when implicit_allow: true but you want to block specific actions.

Step 3: Conditional Policies

Add policies for fine-grained control:

{
  roles: {
    content_editor: {
      implicit_allow: false,
      permissions: [
        {
          permission: "data.entity.read",
          effect: "allow",
          policies: [
            {
              description: "Only read posts and comments",
              condition: { entity: { $in: ["posts", "comments"] } },
              effect: "allow",
            },
          ],
        },
        {
          permission: "data.entity.create",
          effect: "allow",
          policies: [
            {
              condition: { entity: { $in: ["posts", "comments"] } },
              effect: "allow",
            },
          ],
        },
      ],
    },
  },
}

Policy Structure

{
  description?: string,      // Human-readable (optional)
  condition?: ObjectQuery,   // When policy applies
  effect: "allow" | "deny" | "filter",
  filter?: ObjectQuery,      // Row filter (for effect: "filter")
}

Policy Effects

Effect	Purpose
allow	Grant when condition met
deny	Block when condition met
filter	Apply row-level filter to results

Condition Operators

Operator	Description	Example
$eq	Equal	{ entity: { $eq: "posts" } }
$ne	Not equal	{ entity: { $ne: "users" } }
$in	In array	{ entity: { $in: ["posts", "comments"] } }
$nin	Not in array	{ entity: { $nin: ["users", "secrets"] } }
$gt	Greater than	{ age: { $gt: 18 } }
$gte	Greater or equal	{ level: { $gte: 5 } }
$lt	Less than	{ count: { $lt: 100 } }
$lte	Less or equal	{ priority: { $lte: 3 } }

Step 4: Variable Placeholders

Reference runtime context with @variable:

Placeholder	Description
@user.id	Current user's ID
@user.email	Current user's email
@user.role	Current user's role
@entity	Current entity name
@id	Current record ID

Example - user can only update their own profile:

{
  permissions: [
    {
      permission: "data.entity.update",
      effect: "allow",
      policies: [
        {
          condition: { entity: "users", "@id": "@user.id" },
          effect: "allow",
        },
      ],
    },
  ],
}

Step 5: Entity-Specific Permissions

Grant different permissions per entity:

{
  roles: {
    blog_author: {
      implicit_allow: false,
      permissions: [
        // Full CRUD on posts
        {
          permission: "data.entity.read",
          effect: "allow",
          policies: [{ condition: { entity: "posts" }, effect: "allow" }],
        },
        {
          permission: "data.entity.create",
          effect: "allow",
          policies: [{ condition: { entity: "posts" }, effect: "allow" }],
        },
        {
          permission: "data.entity.update",
          effect: "allow",
          policies: [{ condition: { entity: "posts" }, effect: "allow" }],
        },
        {
          permission: "data.entity.delete",
          effect: "allow",
          policies: [{ condition: { entity: "posts" }, effect: "allow" }],
        },

        // Read-only on categories
        {
          permission: "data.entity.read",
          effect: "allow",
          policies: [{ condition: { entity: "categories" }, effect: "allow" }],
        },
      ],
    },
  },
}

Common Patterns

Read-Only Role

{
  roles: {
    viewer: {
      implicit_allow: false,
      permissions: ["data.entity.read"],
    },
  },
}

CRUD Without Delete

{
  roles: {
    contributor: {
      implicit_allow: false,
      permissions: [
        "data.entity.read",
        "data.entity.create",
        "data.entity.update",
        { permission: "data.entity.delete", effect: "deny" },
      ],
    },
  },
}

Admin with Restricted Raw Access

{
  roles: {
    admin: {
      implicit_allow: true,  // Allow all by default
      permissions: [
        // But deny raw database access
        { permission: "data.raw.query", effect: "deny" },
        { permission: "data.raw.mutate", effect: "deny" },
      ],
    },
  },
}

Multi-Entity Role

{
  roles: {
    content_manager: {
      implicit_allow: false,
      permissions: [
        // Content entities: full CRUD
        {
          permission: "data.entity.read",
          effect: "allow",
          policies: [{
            condition: { entity: { $in: ["posts", "pages", "comments", "media"] } },
            effect: "allow",
          }],
        },
        {
          permission: "data.entity.create",
          effect: "allow",
          policies: [{
            condition: { entity: { $in: ["posts", "pages", "comments", "media"] } },
            effect: "allow",
          }],
        },
        {
          permission: "data.entity.update",
          effect: "allow",
          policies: [{
            condition: { entity: { $in: ["posts", "pages", "comments", "media"] } },
            effect: "allow",
          }],
        },
        {
          permission: "data.entity.delete",
          effect: "allow",
          policies: [{
            condition: { entity: { $in: ["posts", "pages", "comments"] } },  // No media delete
            effect: "allow",
          }],
        },
      ],
    },
  },
}

Deny Specific Entity

{
  roles: {
    user: {
      implicit_allow: false,
      permissions: [
        // Can read most entities
        "data.entity.read",
        // But never access secrets entity
        {
          permission: "data.entity.read",
          effect: "deny",
          policies: [{
            condition: { entity: "secrets" },
            effect: "deny",
          }],
        },
      ],
    },
  },
}

Create Helper Function

For complex role definitions:

// helpers/permissions.ts
type EntityPermission = "read" | "create" | "update" | "delete";

function entityPermissions(
  entities: string[],
  actions: EntityPermission[]
) {
  const permMap: Record<EntityPermission, string> = {
    read: "data.entity.read",
    create: "data.entity.create",
    update: "data.entity.update",
    delete: "data.entity.delete",
  };

  return actions.map((action) => ({
    permission: permMap[action],
    effect: "allow" as const,
    policies: [{
      condition: { entity: { $in: entities } },
      effect: "allow" as const,
    }],
  }));
}

// Usage
{
  roles: {
    blog_author: {
      implicit_allow: false,
      permissions: [
        ...entityPermissions(["posts", "comments"], ["read", "create", "update"]),
        ...entityPermissions(["categories", "tags"], ["read"]),
      ],
    },
  },
}

Verification

Test permission assignments:

1. Login as user with role:

curl -X POST http://localhost:7654/api/auth/password/login \
  -H "Content-Type: application/json" \
  -d '{"email": "[email protected]", "password": "password123"}'

2. Test allowed permission:

curl http://localhost:7654/api/data/posts \
  -H "Authorization: Bearer <token>"
# Should return 200 with data

3. Test denied permission:

curl -X DELETE http://localhost:7654/api/data/posts/1 \
  -H "Authorization: Bearer <token>"
# Should return 403 Forbidden

4. Test entity-specific permission:

# If only posts/comments allowed:
curl http://localhost:7654/api/data/users \
  -H "Authorization: Bearer <token>"
# Should return 403 if users entity not in allowed list

Common Pitfalls

Permission Not Taking Effect

Problem: Changed permissions but old behavior persists

Fix: Restart server - role config is loaded at startup:

# Stop and restart
bknd run

Deny Not Overriding

Problem: Deny effect not blocking access

Fix: Check policy condition - deny only applies when condition matches:

// WRONG - no condition, may not match
{ permission: "data.entity.delete", effect: "deny" }

// CORRECT - simple deny at permission level
{
  permissions: [
    "data.entity.read",
    "data.entity.create",
    // Don't include delete at all
  ],
}

Entity Condition Not Matching

Problem: Entity-specific permission not working

Fix: Verify entity name matches exactly:

// WRONG - entity name case matters
{ condition: { entity: "Posts" } }

// CORRECT - use exact entity name
{ condition: { entity: "posts" } }

Multiple Policies Conflict

Problem: Confusing behavior with multiple policies

Fix: Understand evaluation order - first matching policy wins:

{
  policies: [
    // More specific first
    { condition: { entity: "secrets" }, effect: "deny" },
    // General fallback last
    { effect: "allow" },
  ],
}

Variable Placeholder Not Resolving

Problem: @user.id appearing literally in filter

Fix: Variables only work in filter and condition fields:

// CORRECT usage
{
  condition: { "@id": "@user.id" },  // Works
  filter: { user_id: "@user.id" },   // Works
}

DOs and DON'Ts

DO:

• Start with minimal permissions, add as needed
• Use $in operator for multiple entities
• Test each permission after adding
• Use descriptive policy descriptions
• Prefer explicit permissions over implicit_allow

DON'T:

• Grant data.raw.* to non-admin roles (SQL injection risk)
• Use implicit_allow: true with deny policies (confusing)
• Forget to restart server after config changes
• Mix simple strings and extended format unnecessarily
• Over-complicate with too many nested policies

Related Skills

• bknd-create-role - Define new roles
• bknd-row-level-security - Filter data by user ownership
• bknd-protect-endpoint - Secure specific endpoints
• bknd-public-vs-auth - Configure public vs authenticated access
• bknd-setup-auth - Initialize authentication system