BodyParser

Content-type-driven body reading for requests and responses alike.

BodyParser is the implementation behind ParsersRegistry.bodyParser, which App uses to fill Context.body. It classifies the Content-Type header, then delegates structured payloads to SearchParamsParser and FormDataParser through the registry, so nesting and coercion rules stay identical across query strings, form posts and JSON.

BodyParserInterface

interface

interface BodyParserInterface

The public shape of a body parser, implemented by BodyParser.

Assign an alternative implementation to ParsersRegistry.bodyParser through setParsersRegistry to replace body handling framework-wide.

BodyParserInterface.parse()

parse(received: Request | Response | Res): Promise<ParsedBody>

Reads and decodes a body according to its Content-Type.

Parameters

• received — The request, response or Res to read from.

Returns — The decoded body.

BodyParser

class

class BodyParser implements BodyParserInterface

Default BodyParserInterface implementation.

Reads are non-destructive for caller-supplied inputs: the body is cloned before being drained, so a Middleware can inspect a body and still leave it readable downstream. Empty bodies resolve to a null-prototype object from createSafeObject rather than a plain {}, which is what keeps a __proto__ key in a payload from reaching Object.prototype.

BodyParser.parse()

async parse(received: Request | Response | Res): Promise<ParsedBody>

Reads a body and decodes it according to its Content-Type. This can be used for both request and response bodies.

A Res is converted with Res.toNativeResponse first. The content type is read from that source rather than from the clone, because Bun derives it lazily for FormData-backed requests and a clone taken before the derivation does not carry it. The clone itself is skipped for a Res-derived response, which is freshly constructed and unshared.

Parameters

• received — The request, response or Res whose body to read.

Returns — The decoded ParsedBody. A body-less input yields an empty safe object.

Throws — Exception with Status.BAD_REQUEST when the payload is malformed for its declared type — a SyntaxError from decoding is attributed to the client, and the offending content type is attached to the exception. Any other error propagates unchanged.