```

</div>

It is **HIGHLY encouraged** that you write or copy the code, edit it and run it locally.

Using it in your editor is what really shows you the benefits of FastAPI, seeing how little code you have to write, all the type checks, autocompletion, etc.

---

## Install FastAPI

The first step is to install FastAPI.

<img src="/img/tutorial/security/image01.png">

!!! check "Authorize button!"
    You already have a shiny new "Authorize" button.

    And your *path operation* has a little lock in the top-right corner that you can click.

And if you click it, you have a little authorization form to type a `username` and `password` (and other optional fields):

<img src="/img/tutorial/security/image02.png">

!!! note

/** @author Jesse Wilson */
final class Platform {
  static CharMatcher precomputeCharMatcher(CharMatcher matcher) {
    // CharMatcher.precomputed() produces CharMatchers that are maybe a little
    // faster (and that's debatable), but definitely more memory-hungry. We're
    // choosing to turn .precomputed() into a no-op in GWT, because it doesn't
    // seem to be a worthwhile tradeoff in a browser.

}

[data-termynal]:before {
    content: '';
    position: absolute;
    top: 15px;
    left: 15px;
    display: inline-block;
    width: 15px;
    height: 15px;
    border-radius: 50%;
    /* A little hack to display the window buttons in one pseudo element. */
    background: #d9515d;
    -webkit-box-shadow: 25px 0 0 #f4c025, 50px 0 0 #3ec930;
            box-shadow: 25px 0 0 #f4c025, 50px 0 0 #3ec930;
}

   *
   * <p><b>Note:</b> No guarantees are made regarding stability of the representation between
   * versions.
   */
  public byte[] toByteArray() {
    ByteBuffer buff = ByteBuffer.allocate(BYTES).order(ByteOrder.LITTLE_ENDIAN);
    writeTo(buff);
    return buff.array();
  }

  /**
   * Writes to the given {@link ByteBuffer} a byte representation of this instance.
   *

   *
   */
  @J2ktIncompatible
  @GwtIncompatible // Charset not supported by GWT
  public static final Charset UTF_16BE = Charset.forName("UTF-16BE");

  /**
   * UTF-16LE: sixteen-bit UCS Transformation Format, little-endian byte order.
   *
   * <p><b>Java 7+ users:</b> this constant should be treated as deprecated; use {@link
   * java.nio.charset.StandardCharsets#UTF_16LE} instead.
   *
   */
  @J2ktIncompatible

  }

  /** Returns a {@link HashCode} for a sequence of longs, in big-endian order. */
  private static HashCode toHashCode(long... longs) {
    ByteBuffer bb = ByteBuffer.wrap(new byte[longs.length * 8]).order(ByteOrder.LITTLE_ENDIAN);
    for (long x : longs) {
      bb.putLong(x);
    }
    return HashCode.fromBytes(bb.array());
  }

  public void testParanoid() {
    HashFn hf =
        new HashFn() {
          @Override

   * {@code int} value, interpreted in little-endian byte order. The implementation <i>might</i>
   * perform better than its longhand equivalent, but should not perform worse.
   *
   * @since 12.0
   */
  HashCode hashInt(int input);

  /**
   * Shortcut for {@code newHasher().putLong(input).hash()}; returns the hash code for the given
   * {@code long} value, interpreted in little-endian byte order. The implementation <i>might</i>

 * this annotation specifies each of the different sizes for which a test suite should be built. (In
 * a typical case, the features should include {@link CollectionSize#ANY}.) These semantics are thus
 * a little different from those of other Collection-related features such as {@link
 * CollectionFeature} or {@link SetFeature}.
 *
 * <p>However, when {@link CollectionSize.Require} is used to annotate a test it behaves normally

  static final int SAMPLE_MASK = 0xFF;

  /**
   * Compute arrays of valid unicode text, and store it in 3 forms: byte arrays, Strings, and
   * StringBuilders (in a CharSequence[] to make it a little harder for the JVM).
   */
  @BeforeExperiment
  void setUp() {
    final long seed = 99;
    final Random rnd = new Random(seed);
    strings = new String[SAMPLES];
    for (int i = 0; i < SAMPLES; i++) {