Customize validation error response structure

[joekrill]

Currently the validation error response isn't structured in a way that's easily usable by the client without additional parsing.

By default I get something like this (assuming a "email", "name", and "message" field):

{
  "status": "INVALID_ARGUMENT",
  "error": "invalid argument: validation failed",
  "context": {
    "body": [
      "#: validation failed",
      "#/message: length must be >= 10, but got 0",
      "#/name: length must be >= 3, but got 0",
      "#/email: \"\" is not valid \"email\""
    ]
  }
}

So if i want to use that in my UI to show errors on specific fields, I have to manually parse out each. Which actually wouldn't be so bad if the messages were consistent. But, for example, missing required fields get returned like this (and if there are multiple they are returned in the same message):

"#: missing properties: \"requiredField1\", \"requiredFIeld2\"",

I'd like to return something more structured, perhaps like this:

{

  "status": "INVALID_ARGUMENT",
  "error": "invalid argument: validation failed",
  "context": {
     "errors": [
        { 
            "field": "message", 
            "error": "minLength",
            "message": "length must be >= 10, but got 0",
         },
        { 
            "field": "name", 
            "error": "minLength",
            "message": "length must be >= 3, but got 0",
         },
        { 
            "field": "email", 
            "error": "format",
            "message": "\"\" is not valid \"email\"",
         },
        { 
            "field": "requiredField1", 
            "error": "required",
            "message": "requiredField1 is required",
         },
        { 
            "field": "requiredField2", 
            "error": "required",
            "message": "requiredField2 is required",
         }       
     ]
   }
}

Is this possible? It looks like customizing the Validator may work to some extent? Is that possible? But even doing that it seems like this wouldn't help with the required field issue, because according to this that seems to be generated by the underlying jsonschema library? Though I guess if you're customizing the Validator you could use a different library?

Has anyone been able to do anything like this? Is this possible?