Validation functionality (discussion, input wanted)

I’m considering including some functionality for validating user input. Typical things that need to be validated are:

ctx.pathParam("user-id")
ctx.queryParam("isbn")
ctx.formParam("username")

You could potentially include the validate function on the Context:

val isbn = ctx.validate(Param.QUERY, "isbn").matches(isbnRegex).get() ?: throw BadRequestResponse()
val username = ctx.validate(Param.FORM, "username").minLength(5).get() ?: throw BadRequestResponse()

But since there are a lot of possible entry points, a general validation function (util) would probably be better?

val isbn = validate(ctx.queryParam("isbn")).matches(isbnRegex).get() ?: throw BadRequestResponse()
val username = validate(ctx.formParam("username")).minLength(5).get() ?: throw BadRequestResponse()

This issue is intended for discussion. Should the functionality be included? If yes, how should it work?

[tipsy]

Out now as part of 2.2.0 !

[tipsy]

Let me know if you have any comments on it or if you want me to implement a viable version of it.

I like @bchristenson’s suggestion for putting the validator on the Context, with prefix/suffix for param type. Mainly because I’m really excited about the idea of auto-generating nice error messages.

In my last suggestion I removed getOrThrow in favor of just get, because I needed the cast to be part of the get, like getAs<Int>() (getAsOrThrow<Int>(Exception.class) doesn’t work). If we used your approach with asDouble() (etc), we could go back to having getOrThrow():

val age = ctx.validatedQueryParam("age").asInt().getOrThrow()
val username = ctx.validatedFormParam("username").check({ it.length > 10 }).getOrThrow()
val userId = ctx.validatePathParam("user-id").matches("[0-9]").asLong().getOrThrow(MyException.class)