Role-based access control in GraphQL - Step-by-Step Execution

Concept Flow - Role-based access control

User sends GraphQL request

↓

Check user role in context

↓

Check permissions

↓

Allow or deny access

↓

Return data or error

The system checks the user's role before running the query and allows or denies access based on permissions.

Execution Sample

GraphQL

query GetUserData {
  user(id: "123") {
    name
    email
  }
}

A user requests data; the system checks their role to decide if they can see the email.

Execution Table

Step	Action	User Role	Permission Check	Access Result	Returned Data
1	Receive request	editor	Check role 'editor'	Role found	N/A
2	Check permission for 'email' field	editor	Editors allowed email access?	Yes	Proceed
3	Fetch user data	editor	Access granted	Allowed	{name: 'Alice', email: '[e-mail]'}
4	Return response	editor	N/A	Success	{name: 'Alice', email: '[e-mail]'}
5	End	editor	N/A	Request complete	N/A

💡 Request ends after data is returned or access is denied.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
userRole	undefined	editor	editor	editor	editor
permission	undefined	undefined	allowed	allowed	allowed
accessGranted	false	false	true	true	true
responseData	null	null	null	{name, email}	{name, email}

Key Moments - 3 Insights

Why does the system check the user role before fetching data?

The system checks the role first (see Step 1 in execution_table) to decide if the user has permission to access requested fields, preventing unauthorized data access.

What happens if the user role is not found?

If no role is found, the system rejects the request immediately (see concept_flow branch 'No role' leading to 'Reject request'), so no data is fetched or returned.

Why is permission checked for each field?

Permissions can differ per field; checking each field (Step 2) ensures users only see data they are allowed to, protecting sensitive information.

Visual Quiz - 3 Questions

Look at the execution_table, what is the userRole after Step 2?

A undefined

B admin

C editor

D guest

💡 Hint

Check the 'userRole' row in variable_tracker after Step 2.

At which step does the system decide if access is allowed?

A Step 2

B Step 3

C Step 1

D Step 4

💡 Hint

Look at the 'Permission Check' and 'Access Result' columns in execution_table.

If the userRole was 'guest' without email permission, what would change in the execution_table?

A UserRole would change to 'editor'

B Access Result at Step 2 would be 'No', and no data returned

C Permission Check would be skipped

D ResponseData would include email anyway

💡 Hint

Refer to how 'permission' and 'accessGranted' variables affect returned data in variable_tracker.

Concept Snapshot

Role-based access control in GraphQL:
- User role checked before query execution
- Permissions verified per requested field
- Access denied if role missing or insufficient
- Protects sensitive data by limiting field visibility
- Returns data only if access granted

Full Transcript

Role-based access control means the system checks the user's role before running a GraphQL query. It looks at the user's role in the request context and then checks if that role has permission to access each requested field. If the role is missing or does not have permission, the system denies access and does not return the data. This protects sensitive information by only showing data to users allowed to see it. The execution steps show receiving the request, checking role, verifying permissions, fetching data if allowed, and returning the response.