# Abhängigkeiten { #dependencies }

**FastAPI** hat ein sehr mächtiges, aber intuitives **<abbr title="auch bekannt als: Komponenten, Ressourcen, Provider, Services, Injectables">Dependency Injection</abbr>** System.

Es ist so konzipiert, sehr einfach zu verwenden zu sein und es jedem Entwickler sehr leicht zu machen, andere Komponenten mit **FastAPI** zu integrieren.

## Was ist „Dependency Injection“ { #what-is-dependency-injection }

For that, you can use the `WSGIMiddleware` and use it to wrap your WSGI application, for example, Flask, Django, etc.

## Using `WSGIMiddleware` { #using-wsgimiddleware }

You need to import `WSGIMiddleware`.

Then wrap the WSGI (e.g. Flask) app with the middleware.

And then mount that under a path.

{* ../../docs_src/wsgi/tutorial001_py39.py hl[2:3,3] *}

    if (object == this) {
      return true;
    } else if (object instanceof RegularContiguousSet) {
      RegularContiguousSet<?> that = (RegularContiguousSet<?>) object;
      if (this.domain.equals(that.domain)) {
        return this.first().equals(that.first()) && this.last().equals(that.last());
      }
    }
    return super.equals(object);
  }

  // copied to make sure not to use the GWT-emulated version

            "Indicates a Windows NT Server could not be contacted or that objects within the domain are protected such that necessary information could not be retrieved.",
            "The specified domain did not exist.", "The directory name is invalid.", "Access is denied.",

   */
  @CanIgnoreReturnValue
  public static long copy(Readable from, Appendable to) throws IOException {
    // The most common case is that from is a Reader (like InputStreamReader or StringReader) so
    // take advantage of that.
    if (from instanceof Reader) {
      // optimize for common output types which are optimized to deal with char[]
      if (to instanceof StringBuilder) {

   *
   * <p>To ensure that the created instance obeys its contract, the parameters should satisfy the
   * following constraints. This is the callers responsibility and is not enforced here.
   *
   * <ul>
   *   <li>Both {@code xStats} and {@code yStats} must have the same {@code count}.
   *   <li>If that {@code count} is 1, {@code sumOfProductsOfDeltas} must be exactly 0.0.

        DfsReferralData mockData = mock(DfsReferralData.class);

        // Create a DfsReferral instance with the mock data
        DfsReferral dfsReferral = new DfsReferral(mockData);

        // Verify that getData() returns the same mock data object
        assertEquals(mockData, dfsReferral.getData(), "getData() should return the DfsReferralData object passed to the constructor.");
    }

    /**

interface FlowControlListener {
  /**
   * Notification that the receiving stream flow control window has changed.
   * [WindowCounter] generally carries the client view of total and acked bytes.
   */
  fun receivingStreamWindowChanged(
    streamId: Int,
    windowCounter: WindowCounter,
    bufferSize: Long,
  )

  /**
   * Notification that the receiving connection flow control window has changed.

            @Override
            public boolean equals(Object o) {
                return o instanceof DefaultToolchainsBuilderRequest that
                        && Objects.equals(installationToolchainsSource, that.installationToolchainsSource)
                        && Objects.equals(userToolchainsSource, that.userToolchainsSource);
            }

            @Override
            public int hashCode() {

     * @param fields The fields to extract from the document.
     * @param tagFieldNames The names of the fields that contain tags.
     * @param roleFieldName The name of the field that contains role information.
     * @param langFieldName The name of the field that contains language information.
     * @param readingConverter The converter to use for reading fields.