testower/graphql-transformer

Java tool to transform GraphQL requests

graphql-transformer

Java tool to transform GraphQL requests.

Useful in services acting as facades / proxies in front of a graphQL service.

• Add requested fields to query / mutation response (and remove corresponding fields from response)
• Add arguments
• Manipulate arguments

Usage

Add selection field to request

    // Parse GraphQLRequest from String payload
    GraphQLRequest graphQLRequest = new GraphQLRequest(payload, objectMapper);

    // Add selection field to request if not already exists, keep path for added field
    List<String> addedPath = graphQLRequest.addSelectionField("operationName", "parentField1", "parentField2", "newField");
    
    // Convert request to string and send to GraphQL service
    String responsePayload = client.sendRequest(graphQLRequest.writeValueAsString());
    
    // Parse response to JsonNode
    ObjectNode jsonResponse=objectMapper.readValue(responsePayload, ObjectNode.class);
    
    // Remove selectionField if added
    JsonNodeUtil.removeField(jsonResponse, addedPath);

Manipulate argument values

    GraphQLRequest graphQLRequest = new GraphQLRequest(payload, objectMapper);

    // Read argument value
    ArgumentValue argumentValue = graphQLRequest.getArgumentValue("fieldName", "parentField1", "parentField2", "newField");

    // Create or update argument
    graphQLRequest.setArgumentValue("fieldName", "argumentName", new StringValue("argumentValue"));

    // Return to string representation
    String transformedPayload = graphQLRequest.writeValueAsString();