BoxLang Gotchas

Two BoxLang behaviors worth knowing before they cost you an afternoon.

Reserved scope names

server, application, session, request, url, form, cookie, and static are reserved BoxLang scope names. Assigning a variable one of those names silently shadows the built-in scope instead of erroring at parse time, which produces confusing runtime errors.

BoxExpress's own code avoids all of them — undertowServer instead of server, formData instead of form, and the static-file middleware class is named StaticFiles rather than Static. Do the same in your app.

res.json() only serializes plain structs

JSONSerialize() (and therefore res.json()) only serializes literal structs — not BoxLang class instances, even though isStruct() returns true for one and its properties are freely readable via dot access.

req is a Request instance, so res.json( req ) silently returns {} rather than an error, no matter how many of req.method/req.path/req.query actually have values. property declarations and a getMemento() method don't change this. Build a plain struct out of the fields you want instead:

bxsres.json( { method: req.method, path: req.path, query: req.query, params: req.params, body: req.body } )

The same applies to res, or any other class instance — pass res.json() a struct, never an object.