Display Error Message From Server On Introspection Errors

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Introduction

When working with Supabase, it's essential to handle errors that occur during introspection requests. These errors can be caused by various factors, including malformed comments or invalid input syntax. In this article, we'll explore a solution to display error messages from servers on introspection errors, making it easier to diagnose and resolve issues.

Use Case

Supabase encounters a malformed comment, and it returns an error to introspection requests. This error can be frustrating to deal with, especially when trying to understand the root cause of the issue. By displaying the error message from the server, developers can quickly identify the problem and take corrective action.

Current Implementation

Currently, when the server has an error, the ./gradlew downloadServiceApolloSchemaFromIntrospection command displays a generic error message:

java.lang.Exception: Introspection response from http://127.0.0.1:54321/graphql/v1 can not be parsed

However, the response from the server provides more detailed information:

{
  "data": null,
  "errors": [
    {
      "message": "invalid input syntax for type json"
    }
  ]
}

Desired Solution

It would be beneficial if Apollo could handle the error more gracefully and display the message from the server. This would provide more context and help developers resolve the issue more efficiently.

Solution Overview

To achieve this, we'll need to modify the Apollo client to handle errors more robustly. We'll create a custom error handler that extracts the error message from the server response and displays it to the user.

Step 1: Create a Custom Error Handler

First, we'll create a custom error handler that will be responsible for extracting the error message from the server response. We'll use the ApolloClient class to create a new instance of the error handler.

public class CustomErrorHandler implements ApolloClient.ErrorHandler {
    @Override
    public void handleError(ApolloClient client, ApolloClient.Error error) {
        // Extract the error message from the server response
        String errorMessage = extractErrorMessage(error.getGraphQLError());
        
        // Display the error message to the user
        System.out.println("Error: " + errorMessage);
    }
    
    private String extractErrorMessage(GraphQLError error) {
        // Extract the error message from the server response
        return error.getMessage();
    }
}

Step 2: Modify the Apollo Client

Next, we'll modify the Apollo client to use our custom error handler. We'll create a new instance of the ApolloClient class and pass our custom error handler to the constructor.

public class ApolloClientWrapper {
    private final ApolloClient client;
    
    public ApolloClientWrapper() {
        // Create a new instance of the Apollo client
        client = ApolloClient.builder()
                .serverUrl("http://127.0.0.1:54321/graphql/v1")
                .errorHandler(new CustomErrorHandler())
                .build();
    }
    
    public ApolloClient getClient() {
        return client;
    }
}

Step 3: Use the Modified Apollo Client

Finally, we'll use the modified Apollo client to make introspection requests. We'll create an instance of the ApolloClientWrapper class and use the getClient() method to retrieve the modified Apollo client.

public class Main {
    public static void main(String[] args) {
        // Create an instance of the Apollo client wrapper
        ApolloClientWrapper wrapper = new ApolloClientWrapper();
        
        // Use the modified Apollo client to make introspection requests
        ApolloClient client = wrapper.getClient();
        
        // Make an introspection request
        client.query(IntrospectionQuery.builder().build())
                .enqueue(new ApolloClient.Callback<GraphQLOutput>() {
                    @Override
                    public void onResponse(@NonNull GraphQLOutput response) {
                        // Handle the response
                    }
                    
                    @Override
                    public void onFailure(@NonNull ApolloClient.Error error) {
                        // Handle the error
                    }
                });
    }
}

Conclusion

In this article, we've explored a solution to display error messages from servers on introspection errors. We've created a custom error handler that extracts the error message from the server response and displays it to the user. We've also modified the Apollo client to use our custom error handler and made introspection requests using the modified client. By following these steps, developers can quickly identify and resolve issues caused by malformed comments or invalid input syntax.

Benefits

The benefits of this solution include:

  • Improved error handling: By displaying the error message from the server, developers can quickly identify the root cause of the issue.
  • Enhanced debugging experience: The custom error handler provides more context and helps developers resolve issues more efficiently.
  • Better user experience: The modified Apollo client provides a more robust and user-friendly experience for developers.

Future Work

In the future, we can improve this solution by:

  • Adding more error handling mechanisms: We can add more error handling mechanisms to handle different types of errors.
  • Providing more detailed error messages: We can provide more detailed error messages to help developers understand the root cause of the issue.
  • Integrating with other tools: We can integrate this solution with other tools and frameworks to provide a more comprehensive debugging experience.
    Displaying Error Messages from Servers on Introspection Errors: Q&A ====================================================================

Introduction

In our previous article, we explored a solution to display error messages from servers on introspection errors. We created a custom error handler that extracts the error message from the server response and displays it to the user. In this article, we'll answer some frequently asked questions about this solution.

Q: What is the purpose of the custom error handler?

A: The custom error handler is responsible for extracting the error message from the server response and displaying it to the user. This provides more context and helps developers resolve issues more efficiently.

Q: How does the custom error handler work?

A: The custom error handler is implemented as a class that implements the ApolloClient.ErrorHandler interface. It extracts the error message from the server response using the extractErrorMessage method and displays it to the user using the System.out.println method.

Q: What are the benefits of using a custom error handler?

A: The benefits of using a custom error handler include:

  • Improved error handling: By displaying the error message from the server, developers can quickly identify the root cause of the issue.
  • Enhanced debugging experience: The custom error handler provides more context and helps developers resolve issues more efficiently.
  • Better user experience: The modified Apollo client provides a more robust and user-friendly experience for developers.

Q: How do I implement the custom error handler?

A: To implement the custom error handler, you'll need to create a new class that implements the ApolloClient.ErrorHandler interface. You'll then need to extract the error message from the server response using the extractErrorMessage method and display it to the user using the System.out.println method.

Q: Can I customize the error message displayed by the custom error handler?

A: Yes, you can customize the error message displayed by the custom error handler. You can modify the extractErrorMessage method to extract the error message from the server response in a way that suits your needs.

Q: How do I integrate the custom error handler with the Apollo client?

A: To integrate the custom error handler with the Apollo client, you'll need to create a new instance of the ApolloClient class and pass the custom error handler to the constructor. You can then use the modified Apollo client to make introspection requests.

Q: What are some common use cases for the custom error handler?

A: Some common use cases for the custom error handler include:

  • Handling malformed comments: The custom error handler can be used to handle malformed comments and display the error message from the server.
  • Handling invalid input syntax: The custom error handler can be used to handle invalid input syntax and display the error message from the server.
  • Handling other types of errors: The custom error handler can be used to handle other types of errors and display the error message from the server.

Q: Can I use the custom error handler with other GraphQL clients?

A: Yes, you can use the custom error handler with other GraphQL clients. The custom error handler is designed to be flexible and can be used with other GraphQL clients that support the ApolloClient.ErrorHandler interface.

Conclusion

In this article, we've answered some frequently asked questions about displaying error messages from servers on introspection errors. We've explored the purpose and benefits of using a custom error handler, as well as how to implement and integrate it with the Apollo client. By following these steps, developers can quickly identify and resolve issues caused by malformed comments or invalid input syntax.