# Advanced Dependencies { #advanced-dependencies }

## Parameterized dependencies { #parameterized-dependencies }

All the dependencies we have seen are a fixed function or class.

But there could be cases where you want to be able to set parameters on the dependency, without having to declare many different functions or classes.

Let's imagine that we want to have a dependency that checks if the query parameter `q` contains some fixed content.

 * href="https://github.com/google/guava/wiki/StringsExplained#charsets">{@code Charsets}</a>.
 *
 * @author Mike Bostock
 * @since 1.0
 */
@GwtCompatible
public final class Charsets {

  /**
   * US-ASCII: seven-bit ASCII, the Basic Latin block of the Unicode character set (ISO646-US).
   *
   * @deprecated Use {@link StandardCharsets#US_ASCII} instead.
   */
  @Deprecated @J2ktIncompatible @GwtIncompatible // Charset not supported by GWT

		return fmt.Errorf("Expected MinIO binary checksum: %s, seen: %s", s1.Checksum, s2.Checksum)
	}

	ns1 := s1.NEndpoints
	ns2 := s2.NEndpoints
	if ns1 != ns2 {
		return fmt.Errorf("Expected number of endpoints %d, seen %d", ns1, ns2)
	}

	for i, cmdLine := range s1.CmdLines {
		if cmdLine != s2.CmdLines[i] {
			return fmt.Errorf("Expected command line argument %s, seen %s", cmdLine,
				s2.CmdLines[i])
		}
	}

Up to now, you have been using common data types, like:

* `int`
* `float`
* `str`
* `bool`

But you can also use more complex data types.

And you will still have the same features as seen up to now:

* Great editor support.
* Data conversion from incoming requests.
* Data conversion for response data.
* Data validation.
* Automatic annotation and documentation.

# Async Tests { #async-tests }

You have already seen how to test your **FastAPI** applications using the provided `TestClient`. Up to now, you have only seen how to write synchronous tests, without using `async` functions.

  // For example: (long) data[i++] | (long) data[i++] << 8 | ...
  // If data[i] == (byte) 0x80, the first cast will sign-extend it to 0xffffffffffffff80,
  // masking the remaining seven bytes.
  // To test this, we give an input where bit 7 is not cleared. For example:
  // (1) 00 01 02 03 04 05 06 07 80
  // (2) 00 01 02 03 04 05 06 07 81
  // (3) 00 01 02 03 04 05 06 07 ff (or anything in between)

Viele Entwickler und Teams verlassen sich bei ihren Projekten bereits auf **FastAPI** (einschließlich mir und meinem Team).

Dennoch stehen uns noch viele Verbesserungen und Funktionen bevor.

**FastAPI** hat eine große Zukunft vor sich.

## Request and Response

MinIO will make a `POST` request with a JSON body to the given plugin URL. If the auth token parameter is set, it will be sent as an authorization header.

The JSON body structure can be seen from this sample:

<details><summary>Request Body Sample</summary>

```json
{
  "input": {
    "account": "minio",
    "groups": null,
    "action": "s3:ListBucket",
    "bucket": "test",

    if (seenExceptions == null) {
      seenExceptions = newHashSet();
      addInitialException(seenExceptions);
    }
    return seenExceptions;
  }

  abstract void addInitialException(Set<Throwable> seen);

  final int decrementRemainingAndGet() {
    return --remaining;
  }

  final void clearSeenExceptions() {
    seenExceptions = null;
  }

                });

    // To start, fill up the cache.
    // Each miss both increments the counter and causes the map to grow by one,
    // so until evictions begin, the size of the map is the greatest return
    // value seen so far
    while (cache.getUnchecked(nextRandomKey()) < maximumSize) {}

    requests.set(0);
    misses.set(0);
  }

  @Benchmark
  int time(int reps) {
    int dummy = 0;