input method
Gets form field value from request body for x-www-form-urlencoded, JSON, or multipart form data. Also checks URL query parameters. Returns null if key not found. Only returns non-file fields. Priority: Body parameters > Query parameters (body overrides query for same key)
Implementation
Future<dynamic> input(String key) async {
await _ensureParsed();
final fields = _fieldBag[this];
// Check query parameters first, then body fields
// Body fields take precedence over query parameters for same key
final queryValue = uri.queryParameters[key];
final bodyValue = fields != null && fields.containsKey(key)
? fields[key]
: null;
// Return body value if exists, otherwise query value
return bodyValue ?? queryValue;
}