# Tutorial - User Guide { #tutorial-user-guide }

This tutorial shows you how to use **FastAPI** with most of its features, step by step.

Each section gradually builds on the previous ones, but it's structured to separate topics, so that you can go directly to any specific one to solve your specific API needs.

It is also built to work as a future reference so you can come back and see exactly what you need.

## Run the code { #run-the-code }

          }
          canRemoveOrSet = true;
          return forwardIterator.previous();
        }

        @Override
        public int nextIndex() {
          return reversePosition(forwardIterator.nextIndex());
        }

        @Override
        @ParametricNullness
        public T previous() {
          if (!hasPrevious()) {
            throw new NoSuchElementException();
          }

### Set metadata

In below example `minio-go` is used to set the storage class to `REDUCED_REDUNDANCY`. This means this object will be split across 6 data drives and 2 parity drives (as per the storage class set in previous step).

```go
s3Client, err := minio.New("localhost:9000", "YOUR-ACCESSKEYID", "YOUR-SECRETACCESSKEY", true)
if err != nil {
 log.Fatalln(err)
}

object, err := os.Open("my-testfile")
if err != nil {

### Testing an example with awscli tool

> Use the same username and password created in the previous steps.

```
[foobar]
region = us-east-1
aws_access_key_id = foobar
aws_secret_access_key = foo12345
```

</div>

## Update the App with Multiple Models { #update-the-app-with-multiple-models }

Now let's **refactor** this app a bit to increase **security** and **versatility**.

If you check the previous app, in the UI you can see that, up to now, it lets the client decide the `id` of the `Hero` to create. 😱

Я расскажу больше про образы контейнеров, Docker, Kubernetes и т.п. в следующей главе: [FastAPI внутри контейнеров — Docker](docker.md){.internal-link target=_blank}.

///

## Предварительные шаги перед запуском { #previous-steps-before-starting }

Во многих случаях вы захотите выполнить некоторые шаги **перед запуском** приложения.

Например, запустить **миграции базы данных**.

     */
    @Nonnull
    Optional<Boolean> failNever();

    /**
     * Indicates whether Maven should resume from the last failed project in a previous build.
     *
     * @return an {@link Optional} containing true if Maven should resume from the last failure, false if not, or empty if not specified
     */
    @Nonnull
    Optional<Boolean> resume();

    }

    @CanIgnoreReturnValue
    RoundToDoubleTester setExpectation(double expectedValue, RoundingMode... modes) {
      for (RoundingMode mode : modes) {
        Double previous = expectedValues.put(mode, expectedValue);
        if (previous != null) {
          throw new AssertionError();
        }
      }
      return this;
    }

    @CanIgnoreReturnValue

        @Override
        public Integer next(Integer value) {
          return integers().next(value);
        }

        @Override
        public Integer previous(Integer value) {
          return integers().previous(value);
        }

        @Override
        public long distance(Integer start, Integer end) {
          return integers().distance(start, end);
        }
      };

...but continue reading below to see how to overcome that.

## Return Type and Data Filtering { #return-type-and-data-filtering }

Let's continue from the previous example. We wanted to **annotate the function with one type**, but we wanted to be able to return from the function something that actually includes **more data**.