0042; 0062; Case map
   0043; 0063; Case map
   0044; 0064; Case map
   0045; 0065; Case map
   0046; 0066; Case map
   0047; 0067; Case map
   0048; 0068; Case map
   0049; 0069; Case map
   004A; 006A; Case map
   004B; 006B; Case map
   004C; 006C; Case map
   004D; 006D; Case map
   004E; 006E; Case map
   004F; 006F; Case map
   0050; 0070; Case map
   0051; 0071; Case map
   0052; 0072; Case map

    a debug message.

  * If the wagon is bound to "file://" then:

    Retrieve the file or base-url file to be "downloaded".

    * If the file (or more usefully, the base-url file) exists, proceed.

    * If the file (or base-url file) doesn't exist, assume that this location
      is part of a file-share. Ignore the request and print a debug message
      as above.

The contents that you return from your *path operation function* will be put inside of that `Response`.

And if that `Response` has a JSON media type (`application/json`), like is the case with the `JSONResponse` and `UJSONResponse`, the data you return will be automatically converted (and filtered) with any Pydantic `response_model` that you declared in the *path operation decorator*.

!!! note

    Any HTTP (error) status code 401 "UNAUTHORIZED" is supposed to also return a `WWW-Authenticate` header.

    In the case of bearer tokens (our case), the value of that header should be `Bearer`.

    You can actually skip that extra header and it would still work.

    But it's provided here to be compliant with the specifications.

## What is "Dependency Injection"

**"Dependency Injection"** means, in programming, that there is a way for your code (in this case, your *path operation functions*) to declare things that it requires to work and use: "dependencies".

And then, that system (in this case **FastAPI**) will take care of doing whatever is needed to provide your code with those needed dependencies ("inject" the dependencies).

             *
             * In such case, [FirQualifiedAccessExpression] representing the call references
             * the original `Base.bar` callable symbol instead of `MyObject.bar`, because there are
             * no separate symbol for that case.
             *
             * Java statics present a similar case - they can be imported not only from the declaring class,

In this case, it would use the certificate for `someapp.example.com`.

<img src="/img/deployment/https/https03.svg">

The client already **trusts** the entity that generated that TLS certificate (in this case Let's Encrypt, but we'll see about that later), so it can **verify** that the certificate is valid.

### Understand the question

* Check if you can understand what is the **purpose** and use case of the person asking.

* Then check if the question (the vast majority are questions) is **clear**.

* In many cases the question asked is about an imaginary solution from the user, but there might be a **better** one. If you can understand the problem and use case better, you might be able to suggest a better **alternative solution**.

Of course, there are some cases where there's no problem in running the previous steps multiple times, in that case, it's a lot easier to handle.

!!! tip
    Also, keep in mind that depending on your setup, in some cases you **might not even need any previous steps** before starting your application.

    In that case, you wouldn't have to worry about any of this. 🤷

### Examples of Previous Steps Strategies

     *
     * ## Upstream
     *
     * In this case the current thread is assigned as the upstream reader. We read bytes from
     * upstream and copy them to both the file and to the buffer. Finally we release the upstream
     * reader lock and return the new bytes.
     *
     * ## The file
     *
     * In this case we copy bytes from the file to the [sink].
     *
     * ## The buffer
     *