# Usage

## Single Payload Requests

Single payload requests are requests and responses that are sent in a single message.
In essence, they are `[]byte` -> `[]byte, error` functions.

It is not possible to return *both* an error and a response.

Handlers are registered on the manager using `(*Manager).RegisterSingleHandler(id HandlerID, h SingleHandlerFn, subroute ...string)`.

 * matches the insertion order. All optional operations (adding and removing) are supported. All
 * elements, including {@code null}, are permitted.
 *
 * <p>{@code contains(x)}, {@code add(x)} and {@code remove(x)}, are all (expected and amortized)
 * constant time operations. Expected in the hashtable sense (depends on the hash function doing a

   * characters, even though <a href="https://goo.gl/e7E0In">many of these are accepted in modern
   * URLs</a>. (<a href="https://goo.gl/jfVxXW">If the escaper were to leave these characters
   * unescaped, they would be escaped by the consumer at parse time, anyway.</a>) Additionally, the
   * escaper escapes the slash character ("/"). While slashes are acceptable in URL paths, they are

import java.util.concurrent.ExecutionException;

/**
 * A semi-persistent mapping from keys to values. Values are automatically loaded by the cache, and
 * are stored in the cache until either evicted or manually invalidated. The common way to build
 * instances is using {@link CacheBuilder}.
 *
 * <p>Implementations of this interface are expected to be thread-safe, and can be safely accessed
 * by multiple concurrent threads.
 *

```Python hl_lines="2  6"
{!../../../docs_src/advanced_middleware/tutorial003.py!}
```

The following arguments are supported:

* `minimum_size` - Do not GZip responses that are smaller than this minimum size in bytes. Defaults to `500`.

## Other middlewares

There are many other ASGI middlewares.

For example:

import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;
import static com.google.common.collect.testing.google.MultisetFeature.ENTRIES_ARE_VIEWS;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.Iterables;
import com.google.common.collect.Multiset;
import com.google.common.collect.Multisets;

   developers and others in the free software community to coordinate our efforts.

 * **Be pragmatic**: Questions are encouraged and should be asked early in the process to avoid
   problems later. Be thoughtful and considerate when seeking out the appropriate forum for your
   questions. Those who are asked should be responsive and helpful.

 * **Step down considerately**: Members of every project come and go. When somebody leaves or

  int getHash();

  /** Returns the key for this entry. */
  @CheckForNull
  K getKey();

  /*
   * Used by entries that use access order. Access entries are maintained in a doubly-linked list.
   * New entries are added at the tail of the list at write time; stale entries are expired from
   * the head of the list.
   */

  /** Returns the time that this entry was last accessed, in ns. */
  @SuppressWarnings("GoodTime")

# Advanced Security

## Additional Features

There are some extra features to handle security apart from the ones covered in the [Tutorial - User Guide: Security](../../tutorial/security/index.md){.internal-link target=_blank}.

!!! tip
    The next sections are **not necessarily "advanced"**.

    And it's possible that for your use case, the solution is in one of them.

## Read the Tutorial first

        #    e.g. list:{PRODUCT_STATUS ; prefix:TMP_}
        #  This is only for the main schema. Additional schemas are unconcerned.
        #  And ReplaceSchema task basically ignores this.
        #
        #  Normally this 'except' means no getting meta data for excepted tables.
        #  (so the tables are not existing in SchemaHTML and HistoryHTML and so on).
        #  But you can specify the '@gen' suffix that means generate-only except.