# `FastAPI` class

Here's the reference information for the `FastAPI` class, with all its parameters, attributes and methods.

You can import the `FastAPI` class directly from `fastapi`:

```python
from fastapi import FastAPI
```

::: fastapi.FastAPI
    options:
        members:
            - openapi_version
            - webhooks
            - state
            - dependency_overrides
            - openapi

from fastapi import Depends, FastAPI
from typing_extensions import Annotated

app = FastAPI()


class FixedContentQueryChecker:
    def __init__(self, fixed_content: str):
        self.fixed_content = fixed_content

    def __call__(self, q: str = ""):
        if q:
            return self.fixed_content in q
        return False


checker = FixedContentQueryChecker("bar")


@app.get("/query-checker/")

from typing import Annotated

from fastapi import FastAPI, File, UploadFile

app = FastAPI()


@app.post("/files/")
async def create_file(file: Annotated[bytes, File(description="A file read as bytes")]):
    return {"file_size": len(file)}


@app.post("/uploadfile/")
async def create_upload_file(
    file: Annotated[UploadFile, File(description="A file read as UploadFile")],
):

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3

import java.io.IOException
import okhttp3.Interceptor.Chain
import okio.Buffer
import okio.BufferedSink
import okio.ForwardingSink
import okio.Sink
import okio.buffer

/** Rewrites the request body sent to the server to be all uppercase.  */
class UppercaseRequestInterceptor : Interceptor {

 * under the License.
 */
package org.apache.maven.api.plugin.annotations;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Inherited;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import org.apache.maven.api.annotations.Experimental;

/**

 */
package org.codelibs.core.convert;

import static org.hamcrest.CoreMatchers.is;
import static org.hamcrest.CoreMatchers.nullValue;
import static org.junit.Assert.assertThat;

import org.codelibs.core.exception.ClIllegalArgumentException;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;

/**
 * @author wyukawa
 *
 */

 * under the License.
 */
package org.apache.maven.execution;

import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Singleton;

import org.apache.maven.artifact.versioning.ArtifactVersion;
import org.apache.maven.artifact.versioning.DefaultArtifactVersion;
import org.codehaus.plexus.personality.plexus.lifecycle.phase.Initializable;
import org.codehaus.plexus.personality.plexus.lifecycle.phase.InitializationException;

import com.google.common.collect.testing.testers.CollectionCreationTester;
import com.google.common.collect.testing.testers.CollectionEqualsTester;
import com.google.common.collect.testing.testers.CollectionForEachTester;
import com.google.common.collect.testing.testers.CollectionIsEmptyTester;
import com.google.common.collect.testing.testers.CollectionIteratorTester;
import com.google.common.collect.testing.testers.CollectionRemoveAllTester;

 */

package com.google.common.collect;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.Maps.IteratorBasedAbstractMap;
import java.util.Iterator;
import java.util.NavigableMap;
import java.util.NavigableSet;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.SortedMap;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

import okhttp3.Call
import okhttp3.Callback
import okhttp3.Connection
import okhttp3.Cookie
import okhttp3.Credentials.basic
import okhttp3.EventListener
import okhttp3.Headers.Companion.headersOf
import okhttp3.HttpUrl.Companion.toHttpUrl
import okhttp3.Interceptor
import okhttp3.MediaType
import okhttp3.MediaType.Companion.toMediaType
import okhttp3.OkHttpClient
import okhttp3.OkHttpClientTestRule
import okhttp3.Protocol