mod.ts

/**
 * Request interface extension with additional `parsedBody` property (where parsed body gets stored)
 */
export interface ReqWithBody<T = Record<string, unknown>> extends Request {
  parsedBody?: T
}

/**
 * Universal body parser function
 * @param fn request body formatter
 */
export const bodyParser =
  <T>(fn: (body: string) => T) => async (req: ReqWithBody<T>) => {
    const body = await req.text()

    req.parsedBody = fn(body)

    return req.parsedBody
  }

type NextFunction = (err?: Error) => void

/**
 * Parse a request with JSON body and `Content-Type`: `application/json` header.
 * @param req Server request
 * @param _
 * @param next
 */
export const json = async <T = Record<string, unknown>>(
  req: ReqWithBody<T>,
  _?: unknown,
  next?: NextFunction,
) => {
  if (req.headers.get('content-type') === 'application/json') {
    try {
      await bodyParser((x) => JSON.parse(x.toString()))(req)
    } catch (e) {
      next?.(e)
    } finally {
      next?.()
    }
  } else next?.()
}

/**
 * Parse a form with the body and `Content-Type`: `application/x-www-urlencoded` header.
 * @param req Server request
 * @param _
 * @param next
 */
export const urlencoded = async (
  req: ReqWithBody<Record<string, string>>,
  _?: unknown,
  next?: NextFunction,
) => {
  if (req.headers.get('content-type') === 'application/x-www-form-urlencoded') {
    try {
      await bodyParser((x) => {
        const u = new URLSearchParams(x.toString())
        return Object.fromEntries(u.entries())
      })(req)
    } catch (e) {
      next?.(e)
    } finally {
      next?.()
    }
  } else next?.()
}