GraphQL Support

Unlike REST APIs, GraphQL APIs provide a flexible approach to querying and mutating data through a single endpoint. They allow clients to specify exactly what data is needed, reducing over-fetching and under-fetching issues common with REST APIs. GraphQL APIs can be modified to customize requests and responses for testing and debugging. This guide provides detailed steps to achieve this using Requestly.

Modifying GraphQL Responses

In GraphQL, client interactions are typically managed through a single HTTP endpoint. The specific operation to execute is often indicated by the operationName field in the request payload.

Example Request

CopyPOST <https://www.example.com/graphqlapi>
{
  "operationName": "getUsers",
  "query": `
    query getUsers {
      users {
        id
        email
      }
    }
  `
}

To modify the response of a GraphQL API:

Steps to Modify API Response

For additional details, visit the Modify API Response Rule Page.

Notes

• The Key represents the JSON key in the request payload and supports nested paths. For example:

  • If operationName is located at data.operationName, specify data.operationName.

  • For array payloads, such as [{"operationName": "value"}], use 0.operationName as the key.

• If the request does not include operationName, select Resource Type as "REST API" and use Dynamic (JavaScript) Mode to filter and modify the response.

Example Without operationName

In cases where the operation is specified within the query field:

CopyPOST /graphql
{
  "query": `
    query getUsers {
      users {
        id
        email
      }
    }
  `
}

You can modify the response using a JavaScript snippet:

Copyfunction modifyResponse(args) {
  const { url, response, requestData, responseJSON } = args;

  if (requestData.query?.includes("query getUsers")) {
    console.log("Requestly: Modifying response", { query: requestData.query });
    return { ...responseJSON, custom: true };
  }

  return response;
}

Modifying GraphQL Requests

If you need to alter the GraphQL query or its variables, use the Modify Request Body rule to change the request payload dynamically.

Steps to Modify Request Body

Copyfunction modifyRequestBody(args) {
  const { method, url, bodyAsJson } = args;
  let newBody = bodyAsJson;

  if (method === "POST") {
    newBody.query = `query modifyUsers { users { name } }`;
  }

  return newBody;
}

For additional details, visit the Modify Request Rule Page.