# 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)

     */
    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.
     *

 *   <li>SO_TIMEOUT_PROPERTY: Socket timeout setting.</li>
 *   <li>PROXY_HOST_PROPERTY: Proxy host setting.</li>
 *   <li>PROXY_PORT_PROPERTY: Proxy port setting.</li>
 *   <li>PROXY_AUTH_SCHEME_PROPERTY: Proxy authentication scheme.</li>
 *   <li>PROXY_CREDENTIALS_PROPERTY: Proxy credentials.</li>
 *   <li>USER_AGENT_PROPERTY: User agent string.</li>

        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

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

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

   * can't coalesce connections that use a proxy, since proxies don't tell us the origin server's IP
   * address.
   */
  private fun routeMatchesAny(candidates: List<Route>): Boolean =
    candidates.any {
      it.proxy.type() == Proxy.Type.DIRECT &&
        route.proxy.type() == Proxy.Type.DIRECT &&
        route.socketAddress == it.socketAddress
    }

    assertThat(connect1.headers["Proxy-Authorization"]).isNull()
    val connect2 = server.takeRequest()
    assertThat(connect2.requestLine).isEqualTo("CONNECT android.com:443 HTTP/1.1")
    assertThat(connect2.headers["Proxy-Authorization"]).isEqualTo("password")
    val get = server.takeRequest()
    assertThat(get.requestLine).isEqualTo("GET /foo HTTP/2")
    assertThat(get.headers["Proxy-Authorization"]).isNull()
  }