# Environment Variables { #environment-variables }

/// tip

If you already know what "environment variables" are and how to use them, feel free to skip this.

///

An environment variable (also known as "**env var**") is a variable that lives **outside** of the Python code, in the **operating system**, and could be read by your Python code (or by other programs as well).

// CHECKSTYLE_OFF: RegexpHeader
/**
 * This package contains non-functional annotations which are
 * used to tag various elements and help users understanding
 * how those types should be used.
 *
 * @since 4.0.0
 */
@Experimental

)

var etagRegex = regexp.MustCompile("\"*?([^\"]*?)\"*?$")

// Validates the preconditions for CopyObjectPart, returns true if CopyObjectPart
// operation should not proceed. Preconditions supported are:
//
//	x-amz-copy-source-if-modified-since
//	x-amz-copy-source-if-unmodified-since
//	x-amz-copy-source-if-match
//	x-amz-copy-source-if-none-match

-v | output depth and offset details for each value
-h | display help dialog

## Benchmarks

Obligatory benchmarks performed on files with arrays of objects, where the decoded objects are to be extracted.

Two file sizes are used -- regular (1.6mb, 1000 objects) and large (128mb, 100000 objects)

input size | lib | MB/s | Allocated
--- | --- | --- | ---
regular | standard | 97 | 3.6MB
regular | jstream | 175 | 2.1MB

/// note

`PATCH` is less commonly used and known than `PUT`.

And many teams use only `PUT`, even for partial updates.

You are **free** to use them however you want, **FastAPI** doesn't impose any restrictions.

But this guide shows you, more or less, how they are intended to be used.

///

### Using Pydantic's `exclude_unset` parameter { #using-pydantics-exclude-unset-parameter }

## Prerequisites

Configure and install casdoor server by following [Casdoor Server Installation](https://casdoor.org/docs/basic/server-installation).
For a quick installation, docker-compose reference configs are also available on the [Casdoor Try with Docker](https://casdoor.org/docs/basic/try-with-docker).

### Configure Casdoor

- Go to Applications
  - Create or use an existing Casdoor application
  - Edit the application

	// Add grid to router
	router.Handle(grid.RoutePath, adminMiddleware(commonGrid.Handler(storageServerRequestValidate), noGZFlag, noObjLayerFlag))
}

// List of some generic middlewares which are applied for all incoming requests.
var globalMiddlewares = []mux.MiddlewareFunc{
	// set x-amz-request-id header and others
	addCustomHeadersMiddleware,
	// The generic tracer needs to be the first middleware to catch all requests

			Description: `set to change intervals when stale multipart uploads are expired` + defaultHelpPostfix(apiStaleUploadsCleanupInterval),
			Optional:    true,
			Type:        "duration",
		},
		config.HelpKV{
			Key:         apiDeleteCleanupInterval,
			Description: `set to change intervals when deleted objects are permanently deleted from ".trash" folder` + defaultHelpPostfix(apiDeleteCleanupInterval),

    /**
     * The base docs CSS to embed in the HTML
     */
    @InputFile
    @PathSensitive(PathSensitivity.NONE)
    public abstract RegularFileProperty getBaseCssFile();

    /**
     * Key-value pairs that are replaced in the generated HTML.
     *
     * This uses Ant style replacement tokens.
     */
    @Input
    public abstract MapProperty<String, String> getReplacementTokens();

    @Inject

        )


CredentialsDep = Annotated[HTTPAuthorizationCredentials, Depends(HTTPBearer403())]


@app.get("/me")
def read_me(credentials: CredentialsDep):