# 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 }

            Any,
            Doc(
                """
                The type to use for the response.

                It could be any valid Pydantic *field* type. So, it doesn't have to
                be a Pydantic model, it could be other things, like a `list`, `dict`,
                etc.

                It will be used for:

Here's an example of how an HTTPS API could look like, step by step, paying attention mainly to the ideas important for developers.

### Domain Name { #domain-name }

It would probably all start by you **acquiring** some **domain name**. Then, you would configure it in a DNS server (possibly your same cloud provider).

```
.
├── app
│   ├── __init__.py
│   ├── main.py
│   └── test_main.py
```

The file `main.py` would have:

{* ../../docs_src/async_tests/app_a_py39/main.py *}

The file `test_main.py` would have the tests for `main.py`, it could look like this now:

{* ../../docs_src/async_tests/app_a_py39/test_main.py *}

## Run it { #run-it }

You can run your tests as usual via:

     * @return The result of the project building, never {@code null}.
     * @throws ProjectBuildingException If the project descriptor could not be successfully built.
     */
    ProjectBuildingResult build(File projectFile, ProjectBuildingRequest request) throws ProjectBuildingException;

    /**
     * Builds a project descriptor for the specified artifact.

     * @return The version result, never {@code null}.
     * @throws VersionResolverException If the metaversion could not be resolved.
     */
    @Nonnull
    default VersionResolverResult resolve(@Nonnull Session session, @Nonnull ArtifactCoordinates artifactCoordinates)
            throws VersionResolverException {

    private final ModelBuildingResult result;

    /**
     * Creates a new exception with the specified problems.
     *
     * @param model The model that could not be built, may be {@code null}.
     * @param modelId The identifier of the model that could not be built, may be {@code null}.
     * @param problems The problems that causes this exception, may be {@code null}.

package com.google.common.eventbus;

import static com.google.common.base.Preconditions.checkNotNull;

import com.google.common.base.MoreObjects;

/**
 * Wraps an event that was posted, but which had no subscribers and thus could not be delivered.
 *
 * <p>Registering a DeadEvent subscriber is useful for debugging or logging, as it can detect
 * misconfigurations in a system's event distribution.
 *
 * @author Cliff Biffle
 * @since 10.0
 */

### Use cases: external service { #use-cases-external-service }

An example could be that you have an external authentication provider that you need to call.

You send it a token and it returns an authenticated user.

     * @param request The model building request that holds the parameters, must not be {@code null}.
     * @return The result of the model building, never {@code null}.
     * @throws ModelBuildingException If the effective model could not be built.
     */
    ModelBuildingResult build(ModelBuildingRequest request) throws ModelBuildingException;

    /**