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How do I get validation to throw an exception which I can handle?

See original GitHub issue

Hi,

I’m using Javalin (java) version.

I’m using the BodyValidator to coerce a JSON into a class (in this case Customer.class).

I do a few chained check()s.

I want it so that if a check fails that an exception is thrown (potentially with the corresponding error message), so that I can handle it with an exception mapper, and I can return our standard “enveloped response.”

First I’ll show what I mean using curl examples:

Successful POST:

$ curl -i -XPOST -d '{"first_name": "john", "last_name": "doe", "email": "johndoe@example.com"}' http://127.0.0.1:7000/v1/customers; echo
HTTP/1.1 200 OK
Date: Tue, 11 Jun 2019 06:49:15 GMT
Server: Javalin
Content-Type: application/json
Content-Length: 140

{
  "success": true,
  "response": {},
  "timing": [],
  "messages": [
    "customer created"
  ],
  "time": "2019-06-11T06:49:15.479452Z"
}

Invalid POST:

HTTP/1.1 400 Bad Request
Date: Tue, 11 Jun 2019 06:49:24 GMT
Server: Javalin
Content-Type: text/plain
Content-Length: 73

Request body as Customer invalid - 'email' needs to be a non-empty string

For the invalid post I want:

{
  "success": true,
  "response": {},
  "timing": [],
  "messages": [
    "Request body as Customer invalid - 'email' needs to be a non-empty string"
  ],
  "time": <some time>
}

This is the code snippet for how the /v1/customer route is handled:

app.routes(() -> {
    path("/", () -> {
        get("/", ctx -> ctx.result("Hello World"));
        get("/health-check", ctx -> {
            var r = new Envelope(true, new HealthCheckResult(port), null, null);
            ctx.json(r);
        });
    });
    path("/v1", () -> {
        get("/health-check", ctx -> {
            var r = new Envelope(true, new HealthCheckResult(port), null, null);
            ctx.json(r);
        });
        post("/customers", ctx -> {
            var c = ctx.bodyValidator(Customer.class)
                .check(v -> v.getFirstName() != null && !v.getFirstName().isEmpty(), "'first_name' needs to be a non-empty string")
                .check(v -> v.getLastName() != null && !v.getLastName().isEmpty(), "'last_name' needs to be a non-empty string")
                .check(v -> v.getEmailAddress() != null && !v.getEmailAddress().isEmpty(), "'email' needs to be a non-empty string")
                .get();
            // Envelope(success=true, response=null, timing=null, messages=["customer created"])
            var r = new Envelope(true, null, null, List.of("customer created"));
            ctx.json(r);
        });
    });
});