Customizable Error Filtering for js-rpc through User-Defined toError/fromError Functions

[addievo]

Description

Enable user-defined error serialization and deserialization through toError and fromError functions in js-rpc. Add optional replacer and reviver parameters to further customize the (de)serialization process, thereby enhancing security by allowing application-specific rules for sensitive data filtering.

Requirements

1. User-Driven: User should be able to define toError and fromError functions.
2. Optional Parameters: Introduce replacer and reviver for added customization.
3. Application-Specific: Allow injectable rules for data filtering.
4. PK Conformance: Compatibility with existing Polykey workflows.

Tasks

• Parameterize toError and fromError: Accept user-defined implementations.
• Constructor Implementation: Include toError, fromError, replacer, and reviver in the constructor.
• Unit Testing: Create tests for the new features.
• Documentation: Update js-rpc documentation.

Acceptance Criteria

• User-defined toError and fromError functions can be successfully implemented.
• Optional replacer and reviver parameters function as expected.
• The system supports application-specific data filtering rules.
• Documentation is updated.

[CMCDragonkai]

This could be have been in #3.

[addievo]

[addievo]

Updated diagram, removing sensitiveReplacer, no longer required.

[CMCDragonkai]

A single replacer should be sufficient.

What does the API look like?

[addievo]

A single replacer should be sufficient.

What does the API look like?

RIght, sensitive replacer was related stack value of PK. So I will refactor that out.

API of?

[CMCDragonkai]

Give me an example of how it would be used here.

[addievo]

JSON RPC reponse :

{
"jsonrpc": "2.0", 
"error": {
    "code": -32700,
     "message": "Parse error",
     "data?": "Some data",
     "type": ErrorRPCParse,
     }, 
"id": null
}

fromError should return JSONValue object.

replacer is now a parameter too, which works on JSONValue passed by fromError.

replacer should be augemented to be able to extract error from JSON,
the application replacer should work on the library replacer,
since replacer acts on data within an error, i.e. on

"error": {
    "code": -32700,
     "message": "Parse error",
     "data?": "Some data",
     "type": ErrorRPCParse,
     }, 

toError does not necessarily need a reviver as a parameter.

[addievo]

fromError

1. It should now return a JSONValue object instead of a serialized JSON string. This makes it more flexible and allows for further manipulation if needed.

Updated fromError Function - draft

type JSONValue = string | number | boolean | null | { [key: string]: JSONValue } | JSONValue[];
function fromError(error: ErrorRPC<any>, sensitive: boolean = false): JSONValue {
  return {
    type: error.name,
    data: {
      message: error.message,
      code: error.code,
      description: error.description,
    },
  };
}

replacer

1. It should work on the JSONValue object returned by fromError.
2. It should be able to extract data from the error JSON object.

Updated replacer Function - draft

function replacer(key: string, value: any): any {
  if (value instanceof ErrorRPC) {
    return {
      code: value.code,
      message: value.description, 
      "data?": value.someData, 
      type: value.constructor.name, 
    };
  }
  return value;
}

toError

1. Should not necessarily need a reviver as a parameter.

Updated toError Function

function toError(errorData: any, metadata?: JSONValue): Error {
  const error = new Error(); // or any custom error class
  error.message = errorData.message || '';
  // Other custom operations can be performed here
  return error;
}

[CMCDragonkai]

The replacer function might need to be a bit more sophisticated. The replacer actually runs within the error property of the top level JSON object. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify#the_replacer_parameter

You'll need to maintain a sort of context to know if you are under the tree of error property. It's basically a fragment cursor iterating over the tree (graph). So you just don't want to run it on anything other than the error property.

Given that code and message are mandatory properties... you can apply it to any property under error except code and message I reckon.