Struct Binder 

pub struct Binder { /* private fields */ }

Accumulates field-level binding failures into one 400 response.

Binding is best-effort: a bad field records an error and yields None, the remaining fields still bind, and the request is rejected once at the end with every failure listed — matching ASP.NET Core’s ModelState.

Implementations

impl Binder

pub fn new() -> Self

A binder with no recorded errors.

pub fn has_errors(&self) -> bool

Whether any field failed.

pub fn errors(&self) -> &[FieldError]

The recorded failures, in binding order.

pub fn into_error(self) -> Error

Consume the binder, yielding the 400 ProblemDetails error.

The response body carries errors as { "field": ["message"] }.

pub fn missing(&mut self, field: &str)

Record the canonical “required” failure for field.

pub fn invalid(&mut self, field: &str, kind: &str, value: &str)

Record an unparsable value for field.

pub fn unknown_field(&mut self, name: &str)

Record a JSON key that no field claimed (deny_unknown_fields).

pub fn required<T: FromStr>( &mut self, raw: Option<&str>, field: &str, kind: &str, ) -> Option<T>

Parse a required scalar.

Returns None (and records an error) when the value is absent or unparsable; the caller checks Binder::has_errors before building the request.

pub fn optional<T: FromStr>( &mut self, raw: Option<&str>, field: &str, kind: &str, ) -> Option<T>

Parse an optional scalar: absent is None, present-but-invalid is an error (never silently None).

pub fn list<T: FromStr>( &mut self, raw: &[&str], field: &str, kind: &str, ) -> Vec<T>

Parse every occurrence of a repeated value into a list.

An empty list is valid (ASP.NET Core binds missing collections as empty); unparsable elements are errors.

pub fn take<T>(&mut self, value: Option<T>, field: &str) -> Option<T>

Record a “required” failure for an already-extracted optional value.

Used for body fields: serde has already validated the body, so a missing value here means the field was skipped by the shadow struct.

pub fn required_file( &mut self, file: Option<&FormFile>, field: &str, ) -> Option<FormFile>

The first uploaded file, required.

pub fn optional_file(&mut self, file: Option<&FormFile>) -> Option<FormFile>

The first uploaded file, optional.

pub fn files(&mut self, files: Vec<&FormFile>) -> Vec<FormFile>

Every uploaded file under name.

Trait Implementations

impl Default for Binder

fn default() -> Self

Returns the “default value” for a type.