How can I specify which network interface OkHttp will use when establishing new connections

Question

I am using OkHttp within an application I run on a server, and the server has multiple network interfaces configured at the OS level.

How I can control which network interface OkHttp will to use to send new requests?

By default, I see it simply selects one of the interfaces available, where as I would like to provide users of my application built on top of OkHttp the ability to configure the interface which should be used.

Answer 1

I believe you can use

https://square.github.io/okhttp/3.x/okhttp/okhttp3/OkHttpClient.Builder.html#socketFactory-javax.net.SocketFactory-

public OkHttpClient.Builder socketFactory(SocketFactory socketFactory)

Sets the socket factory used to create connections. OkHttp only uses the parameterless createSocket() method to create unconnected sockets. Overriding this method, e. g., allows the socket to be bound to a specific local address. If unset, the system-wide default socket factory will be used.

For example https://github.com/yschimke/okurl/blob/e307022667e2beb474309af5b350cd241f2a9045/src/main/kotlin/com/baulsupp/okurl/network/InterfaceSocketFactory.kt

class InterfaceSocketFactory(private val localAddress: InetAddress) : SocketFactory() {
  private val systemFactory = getDefault()

  override fun createSocket(): Socket {
    val s = systemFactory.createSocket()
    s.bind(InetSocketAddress(localAddress, 0))
    return s
  }