And your **FastAPI** application might also be composed of several files/modules, etc.

### **FastAPI** app file { #fastapi-app-file }

Let's say you have a file structure as described in [Bigger Applications](bigger-applications.md):

```
.
├── app
│   ├── __init__.py
│   └── main.py
```

In the file `main.py` you have your **FastAPI** app:

from fastapi import FastAPI, File, UploadFile

app = FastAPI()


@app.post("/files/")
async def create_file(file: bytes = File()):
    return {"file_size": len(file)}


@app.post("/uploadfile/")
async def create_upload_file(file: UploadFile):

> Please note that losing the `MINIO_KMS_SECRET_KEY` will cause data loss
> since you will not be able to decrypt the IAM/configuration data anymore.
For distributed MinIO deployments, specify the *same* `MINIO_KMS_SECRET_KEY` for each MinIO server process.

At any point in time you can switch from `MINIO_KMS_SECRET_KEY` to a full KMS
deployment. You just need to import the generated key into KES - for example via

    /**
     * File information class for file names only.
     */
    public static final byte FILE_NAMES_INFO = 0x0C;

    /**
     * File information class for both names with file IDs.
     */
    public static final byte FILE_ID_BOTH_DIRECTORY_INFO = 0x24;

    /**
     * File information class for full directory information with file IDs.
     */

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *

     */
    byte SMB_INFO_ALLOCATION = -1;

    /**
     * File system size information constant.
     */
    byte FS_SIZE_INFO = 3;
    /**
     * File system full size information constant.
     */
    byte FS_FULL_SIZE_INFO = 7;

    /**
     * Gets the file system information class.
     *
     * @return file system information class
     */
    byte getFileSystemInformationClass();

/**
 * Filter interface for SMB file filtering.
 *
 * This interface allows selective filtering of files
 * when listing directory contents in SMB shares.
 */
public interface SmbFileFilter {

    /**
     * Tests whether the specified SMB file should be included in a file list.
     *
     * @param file the SMB file to test for inclusion
     * @return whether the given file should be included

{* ../../docs_src/stream_data/tutorial002_py310.py ln[23:27] hl[23] *}

### Simulate a File { #simulate-a-file }

In this example, we are simulating a file with `io.BytesIO`, which is a file-like object that lives only in memory, but lets us use the same interface.

For example, we can iterate over it to consume its contents, as we could with a file.

{* ../../docs_src/stream_data/tutorial002_py310.py ln[1:27] hl[3,12:13,25] *}

@Experimental
public interface Source {
    /**
     * Provides access to the file backing this source, if available.
     * Not all sources are backed by files - for example, in-memory sources
     * or database-backed sources will return null.
     *
     * @return the underlying {@code Path} if this source is file-backed,
     *         or {@code null} if this source has no associated file
     */
    @Nullable
    Path getPath();

    /**

        url = "ftp://example.com/file";
        exp = "example.com/file";
        assertEquals(exp, transformer.getSiteOnFile(url, "UTF-8"));

        url = "s3://my-bucket/path/to/file";
        exp = "my-bucket/path/to/file";
        assertEquals(exp, transformer.getSiteOnFile(url, "UTF-8"));

        url = "gcs://my-bucket/path/to/file";
        exp = "my-bucket/path/to/file";