Function processHeader

lib/core/request.js:446–544

(request, key, val)

}

function processHeader (request, key, val) {
  if (val && (typeof val === 'object' && !Array.isArray(val))) {
    throw new InvalidArgumentError(`invalid ${key} header`)
  } else if (val === undefined) {
    return
  }

  let headerName = headerNameLowerCasedRecord[key]

  if (headerName === undefined) {
    headerName = key.toLowerCase()
    if (headerNameLowerCasedRecord[headerName] === undefined && !isValidHTTPToken(headerName)) {
      throw new InvalidArgumentError('invalid header key')
    }
  }

  if (Array.isArray(val)) {
    const arr = []
    for (let i = 0; i < val.length; i++) {
      if (typeof val[i] === 'string') {
        if (!isValidHeaderValue(val[i])) {
          throw new InvalidArgumentError(`invalid ${key} header`)
        }
        arr.push(val[i])
      } else if (val[i] === null) {
        arr.push('')
      } else if (typeof val[i] === 'object') {
        throw new InvalidArgumentError(`invalid ${key} header`)
      } else {
        // Coerce primitives (and reject unsafe coercions such as functions
        // with a crafted toString/Symbol.toPrimitive).
        const str = `${val[i]}`
        if (!isValidHeaderValue(str)) {
          throw new InvalidArgumentError(`invalid ${key} header`)
        }
        arr.push(str)
      }
    }
    val = arr
  } else if (typeof val === 'string') {
    if (!isValidHeaderValue(val)) {
      throw new InvalidArgumentError(`invalid ${key} header`)
    }
  } else if (val === null) {
    val = ''
  } else {
    // Coerce primitives (and reject unsafe coercions such as functions
    // with a crafted toString/Symbol.toPrimitive).
    val = `${val}`
    if (!isValidHeaderValue(val)) {
      throw new InvalidArgumentError(`invalid ${key} header`)
    }
  }

  if (headerName === 'host') {
    if (request.host !== null) {
      throw new InvalidArgumentError('duplicate host header')
    }