This is not a limitation of **FastAPI**, it's part of the HTTP protocol.

///

## Optional File Upload { #optional-file-upload }

You can make a file optional by using standard type annotations and setting a default value of `None`:

{* ../../docs_src/request_files/tutorial001_02_an_py310.py hl[9,17] *}

	Handler    HandlerID // ID of handler if invoking a remote handler.
	Op         Op        // Operation. Other fields change based on this value.
	Flags      Flags     // Optional flags.
	Payload    []byte    // Optional payload.
}

// Flags is a set of flags set on a message.
type Flags uint8

func (m message) String() string {
	var res []string
	if m.MuxID != 0 {

## First dependency "dependable" { #first-dependency-dependable }

You could create a first dependency ("dependable") like:

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[8:9] *}

It declares an optional query parameter `q` as a `str`, and then it just returns it.

This is quite simple (not very useful), but will help us focus on how the sub-dependencies work.

def get_query(query):
    return f"foo bar {query}"


@app.get("/query/optional")
def get_query_optional(query=None):
    if query is None:
        return "foo bar"
    return f"foo bar {query}"


@app.get("/query/int")
def get_query_type(query: int):
    return f"foo bar {query}"


@app.get("/query/int/optional")
def get_query_type_optional(query: int | None = None):
    if query is None:

import org.codelibs.fess.opensearch.config.exentity.WebConfig;
import org.codelibs.fess.util.ComponentUtil;
import org.codelibs.fess.util.RenderDataUtil;
import org.dbflute.optional.OptionalEntity;
import org.dbflute.optional.OptionalThing;
import org.lastaflute.web.Execute;
import org.lastaflute.web.response.HtmlResponse;
import org.lastaflute.web.response.render.RenderData;

Zum Beispiel deklariert das obige Modell ein JSON „`object`“ (oder Python-<abbr title="Dictionary – Zuordnungstabelle: In anderen Sprachen auch Hash, Map, Objekt, Assoziatives Array genannt">`dict`</abbr>) wie dieses:

```JSON
{
    "name": "Foo",
    "description": "An optional description",
    "price": 45.2,
    "tax": 3.5
}
```

 * under the License.
 */
package org.apache.maven.cling.invoker;

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Objects;
import java.util.Optional;

import org.apache.maven.api.cli.CoreExtensions;
import org.apache.maven.api.cli.InvokerRequest;
import org.apache.maven.api.cli.extensions.CoreExtension;
import org.apache.maven.api.cli.extensions.InputLocation;

# Optional Path parameters are not supported...

# OkHttp test platform rules uses optional classes.

 * under the License.
 */
package org.apache.maven.cling.invoker;

import java.nio.file.Path;
import java.util.HashMap;
import java.util.Map;
import java.util.Optional;
import java.util.Properties;
import java.util.ServiceLoader;
import java.util.function.UnaryOperator;

import org.apache.maven.api.annotations.Nonnull;
import org.apache.maven.api.annotations.Nullable;