veb route with parameter int not checked in type

[jorgeluismireles]

Is there a way to prevent in veb invalid route parametes by type, pass along with its default value instead raising an error?

import veb

pub struct Context {
	veb.Context
}

pub struct App {
}

pub fn (app &App) index(mut ctx Context) veb.Result {
	return ctx.text('Try: localhost:8080/check/byte/one')
}
fn main() {
	mut app := &App{}
	veb.run[App, Context](mut app, 8080)
}

@['/check/byte/:number']
pub fn (app &App) set_number(mut ctx Context, number int) veb.Result {
	match number {
		0...255 {
			return ctx.text('valid byte: ${number}\n') // 200
		}
		else {
			return ctx.request_error('invalid byte: ${number}\n') // 400
		}
	}
}

The last of these four cases says "one" is 0 and valid:

Query	Result
$ curl http://localhost:8080/check/byte/1	valid byte: 1
$ curl http://localhost:8080/check/byte/-1	invalid byte: -1
$ curl http://localhost:8080/check/byte/300	invalid byte: 300
$ curl http://localhost:8080/check/byte/one	valid byte: 0	<<-- ERROR

Changing number to be a result is not accepted:

error: Result type argument is not supported currently
   18 | 
   19 | @['/check/byte/:number']
   20 | pub fn (app &App) set_number(mut ctx Context, number !int) veb.Result {

Changing number to be an option (trying to catch the type problem) yields a panic:

@['/check/byte/:number']
pub fn (app &App) set_number(mut ctx Context, number ?int) veb.Result {
	num := number or {
		return ctx.request_error('number invalid')
	}
	match num {
		0...255 {
			return ctx.text('valid byte: ${number}\n')
		}
		else {
			return ctx.request_error('invalid byte: ${number}\n')
		}
	}
}

V panic: array.get: index out of range (i == 16777224, a.len == 521)
v hash: f24d239
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:22270: at _v_panic: Backtrace
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:21613: by array_get
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:45761: by v__gen__c__Gen_comptime_call
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:40451: by v__gen__c__Gen_expr
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:39249: by v__gen__c__Gen_stmt
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:39045: by v__gen__c__Gen_stmts_with_tmp_var
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:38951: by v__gen__c__Gen_stmts
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:51664: by v__gen__c__Gen_if_expr
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:40491: by v__gen__c__Gen_expr
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:39249: by v__gen__c__Gen_stmt
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:39045: by v__gen__c__Gen_stmts_with_tmp_var
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:38951: by v__gen__c__Gen_stmts
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:51664: by v__gen__c__Gen_if_expr
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:40491: by v__gen__c__Gen_expr
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:39249: by v__gen__c__Gen_stmt
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:39045: by v__gen__c__Gen_stmts_with_tmp_var
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:38951: by v__gen__c__Gen_stmts
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:51664: by v__gen__c__Gen_if_expr
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:40491: by v__gen__c__Gen_expr
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:39249: by v__gen__c__Gen_stmt
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:39045: by v__gen__c__Gen_stmts_with_tmp_var
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:38951: by v__gen__c__Gen_stmts
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:51664: by v__gen__c__Gen_if_expr
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:40491: by v__gen__c__Gen_expr
/tmp/v_1000/v2.01J99FFSCHRYMKXY44ABFK1KDQ.tmp.c:39249: by v__gen__c__Gen_stmt

[medvednikov]

Interesting idea, thanks.

I'll implement it.