///

### Typen und Validierung

Diese Umgebungsvariablen können nur Text-Zeichenketten verarbeiten, da sie außerhalb von Python liegen und mit anderen Programmen und dem Rest des Systems (und sogar mit verschiedenen Betriebssystemen wie Linux, Windows, macOS) kompatibel sein müssen.

---

"_We adopted the **FastAPI** library to spawn a **REST** server that can be queried to obtain **predictions**. [for Ludwig]_"

/// check

Beachten Sie, dass Sie keine spezielle Klasse erstellen und diese irgendwo an **FastAPI** übergeben müssen, um sie zu „registrieren“ oder so ähnlich.

Sie übergeben es einfach an `Depends` und **FastAPI** weiß, wie der Rest erledigt wird.

///

## `Annotated`-Abhängigkeiten wiederverwenden

In den Beispielen oben sehen Sie, dass es ein kleines bisschen **Codeverdoppelung** gibt.

This also means that if you are inside a utility function that you are calling inside of your *path operation function*, and you raise the `HTTPException` from inside of that utility function, it won't run the rest of the code in the *path operation function*, it will terminate that request right away and send the HTTP error from the `HTTPException` to the client.

      byte[] buf = new byte[min(bufSize, MAX_ARRAY_LEN - totalLen)];
      bufs.add(buf);
      int off = 0;
      while (off < buf.length) {
        // always OK to fill buf; its size plus the rest of bufs is never more than MAX_ARRAY_LEN
        int r = in.read(buf, off, buf.length - off);
        if (r == -1) {
          return combineBuffers(bufs, totalLen);
        }
        off += r;
        totalLen += r;

---

"_A gba àwọn ohun èlò ìwé afọwọkọ **FastAPI** tí kò yí padà láti ṣẹ̀dá olùpín **REST** tí a lè béèrè lọ́wọ́ rẹ̀ láti gba **àsọtẹ́lẹ̀**. [fún Ludwig]_"

---

<div style="text-align: left; direction: ltr;">"We adopted the <strong>FastAPI</strong> library to spawn a <strong>REST</strong>server that can be queried to obtain <strong>predictions</strong>. [for Ludwig]"</div>

// PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH RISK ACTIVITIES").  WIDGET WORKSHOP
// SPECIFICALLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR
// HIGH RISK ACTIVITIES.
//
//
// The rest is:
//
// Copyright (C) 1996 by Jef Poskanzer <******@****.***>.  All rights reserved.
//
// Copyright (C) 1996 by Wolfgang Platzer
// email: ******@****.***
//
// All rights reserved.
//

            // Write valid response data
            SMBUtil.writeInt4(15, buffer, 0);
            SMBUtil.writeInt4(16384, buffer, 4);
            SMBUtil.writeInt4(245760, buffer, 8);
            // Fill rest with random data
            for (int i = 12; i < buffer.length; i++) {
                buffer[i] = (byte) (i % 256);
            }

            int bytesDecoded = response.decode(buffer, 0, buffer.length);

/// tip

This is a somewhat advanced technique, and in most of the cases you won't really need it, as you can raise exceptions (including `HTTPException`) from inside of the rest of your application code, for example, in the *path operation function*.

But it's there for you if you need it. 🤓

///

{* ../../docs_src/dependencies/tutorial008b_an_py39.py hl[18:22,31] *}