Basics
GraphQL Errors
Handling GraphQL Errors
GraphQL errors use error fields in response payloads.
Introduction to GraphQL Errors
GraphQL errors are an essential part of the GraphQL specification, providing crucial information about issues that occur during the execution of a query. Unlike traditional REST APIs, where HTTP status codes are often used to indicate errors, GraphQL uses a more structured approach by embedding error details within the response payload.
Structure of a GraphQL Error Response
When a GraphQL query encounters an error, the response payload will contain an errors field. This field is an array of error objects, each containing detailed information about the error. A typical error object may include:
- message: A human-readable description of the error.
- locations: An array specifying where in the query the error occurred, usually with line and column numbers.
- path: An array indicating the path to the field in the response where the error occurred.
- extensions: An optional field for additional application-specific error data.
Common GraphQL Error Types
GraphQL errors can be broadly categorized into two types:
- Syntax Errors: These occur when there are issues with the query syntax, such as missing brackets or invalid fields.
- Execution Errors: These occur during the execution of a query, often due to logical errors or issues with data fetching (e.g., accessing non-existent fields).
Handling GraphQL Errors in Clients
When building a client application, it's crucial to handle GraphQL errors effectively to provide a seamless user experience. Here are some strategies:
- Error Messaging: Display user-friendly error messages that explain what went wrong and how to resolve it.
- Logging: Implement logging mechanisms to capture error details for debugging purposes.
- Retries: For transient errors, consider implementing retry logic.
