# 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 }

```mermaid
sequenceDiagram
    participant Client
    participant Proxy as Proxy/Loadbalancer
    participant Server as FastAPI Server

    Client->>Proxy: HTTPS-Request<br/>Host: mysuperapp.com<br/>Pfad: /items

    Note over Proxy: Proxy fügt Forwarded-Header hinzu

```mermaid
sequenceDiagram
    participant Client
    participant Proxy as Proxy/Load Balancer
    participant Server as FastAPI Server

    Client->>Proxy: HTTPS Request<br/>Host: mysuperapp.com<br/>Path: /items

    Note over Proxy: Proxy adds forwarded headers

```mermaid
sequenceDiagram
    participant Client as Cliente
    participant Proxy as Proxy/Load Balancer
    participant Server as Servidor de FastAPI

    Client->>Proxy: HTTPS Request<br/>Host: mysuperapp.com<br/>Path: /items

    Note over Proxy: El proxy añade headers reenviados

```mermaid
sequenceDiagram
    participant Client as Клиент
    participant Proxy as Прокси/Балансировщик нагрузки
    participant Server as FastAPI-сервер

    Client->>Proxy: HTTPS-запрос<br/>Host: mysuperapp.com<br/>Path: /items

    Note over Proxy: Прокси-сервер добавляет пересылаемые заголовки

Todo este proceso de renovación, mientras aún se sirve la aplicación, es una de las principales razones por las que querrías tener un **sistema separado para gestionar el HTTPS** con un TLS Termination Proxy en lugar de simplemente usar los certificados TLS con el servidor de aplicaciones directamente (por ejemplo, Uvicorn).

## Headers reenviados por el proxy { #proxy-forwarded-headers }

## Cabeçalhos encaminhados por Proxy { #proxy-forwarded-headers }

Ao usar um proxy para lidar com HTTPS, seu servidor de aplicação (por exemplo, Uvicorn via FastAPI CLI) não sabe nada sobre o processo de HTTPS; ele se comunica com HTTP simples com o Proxy de Terminação TLS.

 *   <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>

     */
    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.
     *

        Proxy proxy = repository.getProxy();
        if (proxy != null) {
            if (proxy.getUserName() != null) {
                int hash = (proxy.getUserName() + proxy.getPassword()).hashCode();
                buffer.append(hash).append('@');
            }
            buffer.append(proxy.getHost()).append(':').append(proxy.getPort()).append('>');
        }