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

///

## Optional File Upload

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

//// tab | Python 3.10+

```Python hl_lines="9  17"
{!> ../../docs_src/request_files/tutorial001_02_an_py310.py!}

Documentation = "https://fastapi.tiangolo.com/"
Repository = "https://github.com/fastapi/fastapi"
Issues = "https://github.com/fastapi/fastapi/issues"
Changelog = "https://fastapi.tiangolo.com/release-notes/"

[project.optional-dependencies]

standard = [
    "fastapi-cli[standard] >=0.0.5",
    # For the test client
    "httpx >=0.23.0",
    # For templates
    "jinja2 >=2.11.2",
    # For forms and file uploads

            .add("field11", Arrays.asList("Hello"))
            .add("field12", new ArrayList<>())
            .add("field13", new HashMap<>())
            // Optionals
            .add("field26", Optional.of("World"))
            .add("field27", Optional.absent())
            // Arrays
            .add("field31", new Object[] {"!!!"})
            .add("field32", new boolean[0])
            .add("field33", new byte[0])

import org.gradle.api.Describable
import org.gradle.api.provider.Property
import org.gradle.api.provider.ValueSource
import org.gradle.api.provider.ValueSourceParameters
import org.gradle.api.tasks.Optional


abstract class BuildTimestampFromBuildReceiptValueSource : ValueSource<String, BuildTimestampFromBuildReceiptValueSource.Parameters>, Describable {

    interface Parameters : ValueSourceParameters {

import org.codelibs.fess.es.user.exentity.Group;
import org.codelibs.fess.mylasta.direction.FessConfig;
import org.codelibs.fess.util.ComponentUtil;
import org.dbflute.cbean.result.PagingResultBean;
import org.dbflute.optional.OptionalEntity;

import jakarta.annotation.Resource;

public class GroupService {

    @Resource
    protected GroupBhv groupBhv;

    @Resource
    protected FessConfig fessConfig;

    @Resource

import org.codelibs.fess.es.user.exentity.Role;
import org.codelibs.fess.mylasta.direction.FessConfig;
import org.codelibs.fess.util.ComponentUtil;
import org.dbflute.cbean.result.PagingResultBean;
import org.dbflute.optional.OptionalEntity;

import jakarta.annotation.Resource;

public class RoleService {

    @Resource
    protected RoleBhv roleBhv;

    @Resource
    protected FessConfig fessConfig;

    @Resource

import org.gradle.api.Describable
import org.gradle.api.provider.Property
import org.gradle.api.provider.ValueSource
import org.gradle.api.provider.ValueSourceParameters
import org.gradle.api.tasks.Optional
import java.text.SimpleDateFormat
import java.util.Date
import java.util.TimeZone


abstract class BuildTimestampValueSource : ValueSource<String, BuildTimestampValueSource.Parameters>, Describable {

import com.google.common.collect.testing.features.TesterAnnotation;
import java.lang.annotation.Inherited;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.Set;

/**
 * Optional features of classes derived from {@link Multiset}.
 *
 * @author Louis Wasserman
 */
@SuppressWarnings("rawtypes") // maybe avoidable if we rework the whole package?
@GwtCompatible

import org.codelibs.fess.app.web.api.ApiResult.Status;
import org.codelibs.fess.app.web.base.FessBaseAction;
import org.codelibs.fess.mylasta.action.FessMessages;
import org.dbflute.optional.OptionalThing;
import org.lastaflute.core.message.MessageManager;
import org.lastaflute.web.login.LoginManager;
import org.lastaflute.web.response.ActionResponse;
import org.lastaflute.web.ruts.process.ActionRuntime;

The same assembler is used for all target operating systems and architectures.
The GOOS and GOARCH environment variables set the desired target.

Flags:

	-D name[=value]
		Predefine symbol name with an optional simple value.
		Can be repeated to define multiple symbols.
	-I dir1 -I dir2
		Search for #include files in dir1, dir2, etc,
		after consulting $GOROOT/pkg/$GOOS_$GOARCH.
	-S
		Print assembly and machine code.
	-V