**FastAPI** biedt je het volgende:

### Gebaseerd op open standaarden

* <a href="https://github.com/OAI/OpenAPI-Specification" class="external-link" target="_blank"><strong>OpenAPI</strong></a> voor het maken van API's, inclusief declaraties van <abbr title="ook bekend als: endpoints, routess">pad</abbr><abbr title="ook bekend als HTTP-methoden, zoals POST, GET, PUT, DELETE">bewerkingen</abbr>, parameters, request bodies, beveiliging, enz.

Met **FastAPI** declareer je parameters met type hints en krijg je:

* **Editor ondersteuning**.
* **Type checks**.

...en **FastAPI** gebruikt dezelfde declaraties om:

* **Vereisten te definïeren **: van request pad parameters, query parameters, headers, bodies, dependencies, enz.
* **Data te converteren**: van de request naar het vereiste type.

 *
 */
@Deprecated
public interface ConflictResolver {
    String ROLE = ConflictResolver.class.getName();

    /**
     * Determines which of the specified versions of an artifact to use when there are conflicting declarations.
     *
     * @param node1 the first artifact declaration
     * @param node2 the second artifact declaration

 * for use in test code.
 *
 * <p><b>Do not use this interface</b> for public or protected declarations: it is a fig leaf for
 * bad design, and it does not prevent anyone from using the declaration---and experience has shown
 * that they will. If the method breaks the encapsulation of its class, then its internal
 * representation will be hard to change. Instead, use <a

```JSON
{"item_id":3}
```

/// check

Notice that the value your function received (and returned) is `3`, as a Python `int`, not a string `"3"`.

So, with that type declaration, **FastAPI** gives you automatic request <abbr title="converting the string that comes from an HTTP request into Python data">"parsing"</abbr>.

///

## Data validation { #data-validation }

of the last non-empty expression list.
</p>


<h3 id="Type_declarations">Type declarations</h3>

<p>
A type declaration binds an identifier, the <i>type name</i>, to a <a href="#Types">type</a>.
Type declarations come in two forms: alias declarations and type definitions.
</p>

<pre class="ebnf">
TypeDecl = "type" ( TypeSpec | "(" { TypeSpec ";" } ")" ) .

## Mélanger les paramètres `Path`, `Query` et body

Tout d'abord, sachez que vous pouvez mélanger les déclarations des paramètres `Path`, `Query` et body, **FastAPI** saura quoi faire.

Vous pouvez également déclarer des paramètres body comme étant optionnels, en leur assignant une valeur par défaut à `None` :

```Python
my_list: list[str]
```

In versions of Python before 3.9, it would be:

```Python
from typing import List

my_list: List[str]
```

That's all standard Python syntax for type declarations.

Use that same standard syntax for model attributes with internal types.

So, in our example, we can make `tags` be specifically a "list of strings":

   */
  private final @Nullable Object annotatedType;

  Parameter(
      Invokable<?, ?> declaration,
      int position,
      TypeToken<?> type,
      Annotation[] annotations,
      @Nullable Object annotatedType) {
    this.declaration = declaration;
    this.position = position;
    this.type = type;
    this.annotations = ImmutableList.copyOf(annotations);

Déclarez ensuite votre modèle de données en tant que classe qui hérite de `BaseModel`.

Utilisez les types Python standard pour tous les attributs :

{* ../../docs_src/body/tutorial001.py hl[7:11] *}