There was also an "OpenID" specification. That tried to solve the same thing as **OpenID Connect**, but was not based on OAuth2.

So, it was a complete additional system.

It is not very popular or used nowadays.

## OpenAPI { #openapi }

OpenAPI (previously known as Swagger) is the open specification for building APIs (now part of the Linux Foundation).

  JAVA_HOME("java.home"),

  /** Java Virtual Machine specification version. */
  JAVA_VM_SPECIFICATION_VERSION("java.vm.specification.version"),

  /** Java Virtual Machine specification vendor. */
  JAVA_VM_SPECIFICATION_VENDOR("java.vm.specification.vendor"),

  /** Java Virtual Machine specification name. */
  JAVA_VM_SPECIFICATION_NAME("java.vm.specification.name"),

  /** Java Virtual Machine implementation version. */

* <a href="https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.1.0.md#parameter-object" class="external-link" target="_blank">`Parameter Object` (in the specification)</a> that was used by FastAPI's:
    * `Path()`
    * `Query()`
    * `Header()`
    * `Cookie()`

   * specification.
   *
   * <p>This escaper substitutes {@code 0xFFFD} for non-whitespace control characters and the
   * character values {@code 0xFFFE} and {@code 0xFFFF} which are not permitted in XML. For more
   * detail see section <a href="http://www.w3.org/TR/2008/REC-xml-20081126/#charsets">2.2</a> of
   * the XML specification.
   *

As you see, the method names now have the tag and then the function name, now they don't include information from the URL path and the HTTP operation.

### Preprocess the OpenAPI Specification for the Client Generator { #preprocess-the-openapi-specification-for-the-client-generator }

The generated code still has some **duplicated information**.

`Path()`, `Query()`, `Header()`, &amp; `Cookie()`, `example` ⚖️ `examples` 🚮 <a href="https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.0.3.md#parameter-object" class="external-link" target="_blank">🗄 🔑, `Parameter Object` (🔧)</a>.

`example` e `examples` são adicionados a <a href="https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.0.3.md#parameter-object" class="external-link" target="_blank">definição do OpenAPI, dentro do `Parameter Object` (na especificação)</a>.

E para `Body()`, `File()`, e `Form()`, o `example` e `examples` são de maneira equivalente adicionados para a <a href="https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.0.3.md#mediaTypeObject" class="external-link" target="_blank">definição...

{* ../../docs_src/request_forms/tutorial001_an_py39.py hl[9] *}

For example, in one of the ways the OAuth2 specification can be used (called "password flow") it is required to send a `username` and `password` as form fields.

The <abbr title="specification">spec</abbr> requires the fields to be exactly named `username` and `password`, and to be sent as form fields, not JSON.

   * @param key the value to be searched for.
   * @param comparator the comparator by which the list is ordered.
   * @param presentBehavior the specification for what to do if at least one element of the list
   *     compares as equal to the key.
   * @param absentBehavior the specification for what to do if no elements of the list compare as
   *     equal to the key.

/**
 * Base class for SMB Witness Protocol RPC messages as defined in MS-SWN specification.
 * This class extends DcerpcMessage to provide witness-specific RPC operations.
 */
public abstract class WitnessRpcMessage extends DcerpcMessage {

    // MS-SWN Witness Protocol Interface UUID and Version
    /** Witness Protocol Interface UUID from MS-SWN specification */