Headers

Arbitrary headers can be set on the request using the .header method:

import sttp.client4._

basicRequest.header("User-Agent", "myapp")

As with any other request definition modifier, this method will yield a new request, which has the given header set. The headers can be set at any point when defining the request, arbitrarily interleaved with other modifiers.

While most headers should be set only once on a request, HTTP allows setting a header multiple times, or with multiple values. That’s why the header method has an additional parameter, onDuplicate, which by default is set to DuplicateHeaderBehavior.Replace. This way, if the same header is specified twice, only the last value will be included in the request. Alternatively:

• if previous values should be preserved, set this parameter to DuplicateHeaderBehavior.Add

• if the values of the headers should be combined using ,, or in case of cookies with ;, use DuplicateHeaderBehavior.Combine

There are also variants of this method accepting a number of headers:

import sttp.client4._
import sttp.model._

basicRequest.header(Header("k1", "v1"), onDuplicate = DuplicateHeaderBehavior.Add)
basicRequest.header("k2", "v2")
basicRequest.header("k3", "v3", DuplicateHeaderBehavior.Combine)
basicRequest.headers(Map("k4" -> "v4", "k5" -> "v5"))
basicRequest.headers(Header("k9", "v9"), Header("k10", "v10"), Header("k11", "v11"))

Common headers

For some common headers, dedicated methods are provided:

import sttp.client4._

basicRequest.contentType("application/json")
basicRequest.contentType("application/json", "iso-8859-1")
basicRequest.contentLength(128)
basicRequest.acceptEncoding("gzip, deflate")

See also documentation on setting cookies and authentication.