Why error handling differs from REST in GraphQL - Challenge Your Understanding

Challenge - 5 Problems

🧠 Conceptual

intermediate

How does GraphQL error handling differ from REST?

In REST APIs, errors are usually indicated by HTTP status codes. How does GraphQL handle errors differently?

A GraphQL returns errors only in HTTP headers, not in the response body.

B GraphQL uses HTTP status codes like 404 or 500 to indicate errors, similar to REST.

C GraphQL always returns HTTP 200 status and includes errors inside the response body under an 'errors' field.

D GraphQL does not provide any error information in the response.

💡 Hint

Think about how GraphQL separates transport status from query execution results.

GraphQL typically returns HTTP 200 status even if there are errors in the query. The errors are included inside the response body under an 'errors' field. This differs from REST where HTTP status codes indicate success or failure.

❓ query_result

intermediate

Identify the GraphQL error response structure

Given a GraphQL query that requests a user by ID but the user does not exist, which response shows the correct error handling?

GraphQL

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

A { "data": { "user": null }, "errors": [{ "message": "User not found", "path": ["user"] }] }

B { "error": "User not found", "status": 404 }

C { "data": null, "status": 404 }

D { "data": { "user": { "name": "", "email": "" } } }

💡 Hint

Look for the 'errors' field inside the response body.

GraphQL responses include an 'errors' array alongside 'data'. Even if the user is not found, the HTTP status is 200, and the error details are inside the 'errors' field.

📝 Syntax

advanced

Which GraphQL error response is syntactically valid?

Select the syntactically valid GraphQL error response JSON for a failed query.

A { "data": null, "errors": [{ "message": "Invalid query" }] }

B { data: null, errors: [{ message: "Invalid query" }] }

C { "data": null, "errors": { "message": "Invalid query" } }

D { "data": null, "errors": [{ message: "Invalid query" }] }

💡 Hint

Remember JSON requires double quotes around keys and string values.

Option A is valid JSON with double quotes around keys and string values. Options A and D lack quotes around keys, and C uses an object instead of an array for 'errors'.

❓ optimization

advanced

Optimizing error handling in GraphQL responses

Which approach best optimizes error handling in GraphQL to avoid sending unnecessary data when a critical error occurs?

A Always return full data even if errors occur to keep response size consistent.

B Return null for 'data' and include detailed error messages in the 'errors' array.

C Return partial data with errors and let the client handle missing fields.

D Use HTTP status codes to indicate errors and omit the 'errors' field.

💡 Hint

Consider how to clearly communicate critical failures without confusing partial data.

Returning null for 'data' with detailed errors clearly signals a critical failure. Partial data with errors can confuse clients, and HTTP status codes are not reliable for GraphQL errors.

🔧 Debug

expert

Why does this GraphQL client fail to detect errors?

A client sends a GraphQL query and checks HTTP status code to detect errors. It ignores the response body. Why might this approach fail?

A Because the client must parse XML responses to find errors.

B Because the client should check HTTP headers for error details instead.

C Because GraphQL never returns errors in the response body, only status codes.

D Because GraphQL returns HTTP 200 status even when there are errors inside the response body.

💡 Hint

Think about how GraphQL separates transport success from query success.

GraphQL uses HTTP 200 status for all responses, including those with errors. Errors are inside the response body, so checking only HTTP status misses them.