---
  Getting to Plexus-configured Mojos
  ---
  John Casey
  ---
  2005-04-29

Abstract

  We're moving toward integrating mojos as first-class plexus components, while
  at the same time avoiding introducing required plexus dependencies into the
  mojo development model.

  In order to really achieve this, we need mojo configurations (which are
  provided both in terms of static expressions that are just looked up, and

We are going to include this `APIRouter` in the main `FastAPI` app, but first, let's check the dependencies and another `APIRouter`.

## Dependencies

We see that we are going to need some dependencies used in several places of the application.

So we put them in their own `dependencies` module (`app/dependencies.py`).

    // cheats and does not attempt every possible permutation. Instead, it only considers wildcards
    // in the leftmost position. We assert this fact when we generate the public suffix file. If
    // this assertion ever fails we'll need to refactor this implementation.
    var wildcardMatch: String? = null
    if (domainLabelsUtf8Bytes.size > 1) {
      val labelsWithWildcard = domainLabelsUtf8Bytes.clone()

        // If we are at a super-type constructor call, adjust the resolution expression so that we
        // get the constructor instead of the class.
        //
        // For the example:
        //
        // class A {
        //   constructor()
        // }
        // class B: <caret>A()
        //

 that currently we have information about a project scattered across the project.xml and the
 various properties files. What needs to be done is to encapsulate all of this in the POM.

 Typically users parameterize the use of plugins, or have custom values like ${user.name}
 for use in elements like the <developerConnection/>. It would be idea if we

    //     we find them, regardless of what the address policies need.
    //
    //  2. EVICTABLE: Connections not required by any address policy. This matches connections that
    //     don't participate in any policy, plus connections whose policies won't be violated if the
    //     connection is closed. We only close these if the idle connection limit is exceeded.
    //

```

## Create Pydantic models

As **Couchbase** "documents" are actually just "JSON objects", we can model them with Pydantic.

### `User` model

First, let's create a `User` model:

```Python hl_lines="24-28"
{!../../../docs_src/nosql_databases/tutorial001.py!}
```

We will use this model in our *path operation function*, so, we don't include in it the `hashed_password`.

### `UserInDB` model

        }

        if (errorExceptionToDeliver != null) {
          // We defer throwing the exception until now so that we can refill the connection
          // flow-control window. This is necessary because we don't transmit window updates until
          // the application reads the data. If we throw this prior to updating the connection
          // flow-control window, we risk having it go to 0 preventing the server from sending data.

We can use **OAuth2** to build that with **FastAPI**.

But let's save you the time of reading the full long specification just to find those little pieces of information you need.

Let's use the tools provided by **FastAPI** to handle security.

## How it looks

Let's first just use the code and see how it works, and then we'll come back to understand what's happening.

We can also use this same approach to access the request body in an exception handler.

All we need to do is handle the request inside a `try`/`except` block:

```Python hl_lines="13  15"
{!../../../docs_src/custom_request_and_route/tutorial002.py!}
```

If an exception occurs, the`Request` instance will still be in scope, so we can read and make use of the request body when handling the error: