# Simple OAuth2 with Password and Bearer

Now let's build from the previous chapter and add the missing parts to have a complete security flow.

## Get the `username` and `password`

We are going to use **FastAPI** security utilities to get the `username` and `password`.

OAuth2 specifies that when using the "password flow" (that we are using) the client/user must send a `username` and `password` fields as form data.

Nils Lindemann <******@****.***> 1711822124 +0100

DoHyun Kim <******@****.***> 1712097443 +0900

    val multipart =
      """
      |--simple boundary
      |
      |abcd
      |--simple boundary--
      """.trimMargin()
        .replace(Regex("(?m)simple boundary$"), "simple boundary \t \t")
        .replace("\n", "\r\n")

    val parts =
      MultipartReader(
        boundary = "simple boundary",
        source = Buffer().writeUtf8(multipart),
      )

* Share database connections.
* Enforce security, authentication, role requirements, etc.
* And many other things...

All these, while minimizing code repetition.

## First Steps

Let's see a very simple example. It will be so simple that it is not very useful, for now.

But this way we can focus on how the **Dependency Injection** system works.

### Create a dependency, or "dependable"

Let's first focus on the dependency.

state of the world. It is regenerated (usually partially) on each configuration push (more on this below). Due to being a snapshot, most lookups are lock-free.

`PushContext` is built up by querying the above layers. For some simple use cases, this is as simple as storing something like `configstore.List(SomeType)`; in this case, the only difference from directly exposing the configstore is to snapshot the current state. In other cases, some pre-computations and indexes are computed to make...

Requests a un design très simple et intuitif, il est très facile à utiliser, avec des valeurs par défaut raisonnables, tout en étant très puissant et personnalisable.

C'est pourquoi, comme le dit le site officiel :

> Requests est l'un des packages Python les plus téléchargés de tous les temps

La façon dont vous l'utilisez est très simple. Par exemple, pour faire une requête `GET`, vous devez écrire :

Here are some examples of when that could make sense:

#### A Simple App

You could want a process manager in the container if your application is **simple enough** that you don't need (at least not yet) to fine-tune the number of processes too much, and you can just use an automated default (with the official Docker image), and you are running it on a **single server**, not a cluster.

#### Docker Compose

    val jetty = "org.eclipse.jetty:jetty-http"
    val jettySecurity = "org.eclipse.jetty:jetty-security"
    val jettyWebApp = "org.eclipse.jetty:jetty-webapp"
    val joptSimple = "net.sf.jopt-simple:jopt-simple"
    val jsoup = "org.jsoup:jsoup"
    val jtar = "org.kamranzafar:jtar"
    val kotlinCoroutines = "org.jetbrains.kotlinx:kotlinx-coroutines-core"

They are, more or less, at opposite ends, complementing each other.

Requests has a very simple and intuitive design, it's very easy to use, with sensible defaults. But at the same time, it's very powerful and customizable.

That's why, as said in the official website:

> Requests is one of the most downloaded Python packages of all time

The way you use it is very simple. For example, to do a `GET` request, you would write:

```Python