# Behind a Proxy { #behind-a-proxy }

In many situations, you would use a **proxy** like Traefik or Nginx in front of your FastAPI app.

These proxies could handle HTTPS certificates and other things.

## Proxy Forwarded Headers { #proxy-forwarded-headers }

    * Otherwise, you might have to stop the TLS Termination Proxy momentarily, start the renewal program to acquire the certificates, then configure them with the TLS Termination Proxy, and then restart the TLS Termination Proxy. This is not ideal, as your app(s) will not be available during the time that the TLS Termination Proxy is off.

      // If we used the ProxySelector, and got a IOException during connect, report the failure.
      if (route.address.proxy == null && route.proxy.type() != Proxy.Type.DIRECT) {
        route.address.proxySelector.connectFailed(
          route.address.url.toUri(),
          route.proxy.address(),
          e,
        )
      }
      user.connectFailed(route, null, e)

  }

  @AfterEach
  fun tearDown() {
    socksProxy.shutdown()
  }

  @Test
  fun proxy() {
    server.enqueue(MockResponse.Builder().body("abc").build())
    server.enqueue(MockResponse.Builder().body("def").build())
    val client =
      clientTestRule
        .newClientBuilder()
        .proxy(socksProxy.proxy())
        .build()
    val request1 = Request.Builder().url(server.url("/")).build()

    var client = OkHttpClient.Builder().build()
    assertThat(client.proxy).isNull()
    assertThat(client.proxySelector)
      .isNotInstanceOf(NullProxySelector::class.java)
    client =
      OkHttpClient
        .Builder()
        .proxy(Proxy.NO_PROXY)
        .build()
    assertThat(client.proxy).isSameAs(Proxy.NO_PROXY)
    assertThat(client.proxySelector)

import java.io.Serializable;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.Set;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Generates a dummy interface proxy that simply returns a dummy value for each method.
 *
 * @author Ben Yu
 */
@GwtIncompatible

        assertNull(request.proxy());
        assertNull(request.body());
    }

    @Test
    public void testProxyMethod() {
        CurlRequest request = new CurlRequest(Method.GET, "https://example.com");
        Proxy proxy = Proxy.NO_PROXY;

        CurlRequest result = request.proxy(proxy);

        assertSame(request, result); // Fluent API
        assertSame(proxy, request.proxy());
    }

    @Test

     */
    public String body() {
        return body;
    }

    /**
     * Sets the proxy for the request.
     *
     * @param proxy the proxy
     * @return this CurlRequest instance
     */
    public CurlRequest proxy(final Proxy proxy) {
        this.proxy = proxy;
        return this;
    }

    /**
     * Sets the character encoding for the request.
     *

  fun proxyMoveTest(cleanClose: Boolean) {
    // Define a single Proxy at myproxy:8008 that will artificially move during the test
    val proxySelector = RecordingProxySelector()
    val socketAddress = InetSocketAddress.createUnresolved("myproxy", 8008)
    proxySelector.proxies.add(Proxy(Proxy.Type.HTTP, socketAddress))

    // Define two host names for the DNS routing of fake proxy servers

import java.io.Serializable;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.Set;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Generates a dummy interface proxy that simply returns a dummy value for each method.
 *
 * @author Ben Yu
 */
@GwtIncompatible