To achieve this, the `:80`-backend must have a list of "allowed origins".

In this case, the list would have to include `http://localhost:8080` for the `:8080`-frontend to work correctly.

## Wildcards { #wildcards }

It's also possible to declare the list as `"*"` (a "wildcard") to say that all are allowed.

    validation_alias: Annotated[
        Union[str, AliasPath, AliasChoices, None],
        Doc(
            """
            'Whitelist' validation step. The parameter field will be the single one
            allowed by the alias or set of aliases defined.
            """
        ),
    ] = None,
    serialization_alias: Annotated[
        Union[str, None],
        Doc(
            """

    /**
     * Sets the fields that are allowed in API responses.
     *
     * @param fields array of field names that are allowed in API responses
     */
    public void setApiResponseFields(final String[] fields) {
        apiResponseFieldSet = new HashSet<>();
        Collections.addAll(apiResponseFieldSet, fields);
    }

    /**
     * Checks if the specified field is allowed in API responses.
     *

app = FastAPI()


class InternalError(Exception):
    pass


def get_username():
    try:
        yield "Rick"
    except InternalError:
        print("We don't swallow the internal error here, we raise again 😎")
        raise


@app.get("/items/{item_id}")
def get_item(item_id: str, username: str = Depends(get_username)):
    if item_id == "portal-gun":
        raise InternalError(

    assertEquals(2, factory2.newThread(monitoredRunnable).getPriority());
  }

  public void testBuildTwice() {
    ThreadFactory unused;
    unused = builder.build(); // this is allowed
    unused = builder.build(); // this is *also* allowed
  }

  public void testBuildMutate() {
    ThreadFactory factory1 = builder.setPriority(1).build();
    assertEquals(1, factory1.newThread(monitoredRunnable).getPriority());

The following arguments are supported:

* `allowed_hosts` - A list of domain names that should be allowed as hostnames. Wildcard domains such as `*.example.com` are supported for matching subdomains. To allow any hostname either use `allowed_hosts=["*"]` or omit the middleware.
* `www_redirect` - If set to True, requests to non-www versions of the allowed hosts will be redirected to their www counterparts. Defaults to `True`.

    assertEquals(2, factory2.newThread(monitoredRunnable).getPriority());
  }

  public void testBuildTwice() {
    ThreadFactory unused;
    unused = builder.build(); // this is allowed
    unused = builder.build(); // this is *also* allowed
  }

  public void testBuildMutate() {
    ThreadFactory factory1 = builder.setPriority(1).build();
    assertEquals(1, factory1.newThread(monitoredRunnable).getPriority());

    } catch (ClassCastException acceptable) {
      // allowed by the spec
    }
  }

  public void testContainsEntryWithIncomparableValue() {
    try {
      assertFalse(getMap().entrySet().contains(mapEntry(k0(), IncomparableType.INSTANCE)));
    } catch (ClassCastException acceptable) {
      // allowed by the spec
    }
  }

  @MapFeature.Require(ALLOWS_NULL_KEY_QUERIES)

    } catch (ClassCastException acceptable) {
      // allowed by the spec
    }
  }

  public void testContainsEntryWithIncomparableValue() {
    try {
      assertFalse(getMap().entrySet().contains(mapEntry(k0(), IncomparableType.INSTANCE)));
    } catch (ClassCastException acceptable) {
      // allowed by the spec
    }
  }

  @MapFeature.Require(ALLOWS_NULL_KEY_QUERIES)

 * </p>
 * <ul>
 *   <li>Initialize the client with SMB authentication details.</li>
 *   <li>Retrieve content and metadata from SMB files.</li>
 *   <li>Process access control entries to determine allowed and denied SIDs (Security Identifiers).</li>
 *   <li>Handle timeouts during SMB operations.</li>
 * </ul>
 *
 * <p>
 * The client uses a {@link SmbAuthenticationHolder} to manage SMB authentication credentials.