You could also use it to generate code automatically, for clients that communicate with your API. For example, frontend, mobile or IoT applications.

## Recap, step by step { #recap-step-by-step }

### Step 1: import `FastAPI` { #step-1-import-fastapi }

{* ../../docs_src/first_steps/tutorial001.py hl[1] *}

`FastAPI` is a Python class that provides all the functionality for your API.

        assertFalse(cacheEntry.isComplete());

        // Step 3: Verify can cache directory listing
        assertTrue(directoryLeaseManager.canCacheDirectoryListing(directoryPath));

        // Step 4: Initially no cached listing
        assertNull(directoryLeaseManager.getCachedDirectoryListing(directoryPath));

        // Step 5: Simulate directory enumeration and update cache

        run: ./mvnw -B -P!standard-with-extra-repos -Dtoolchain.skip verify -U -Dmaven.javadoc.skip=true -Dsurefire.toolchain.version=${{ matrix.java }} -f $ROOT_POM
      - name: 'Print Surefire reports'
        # Note: Normally a step won't run if the job has failed, but this causes it to
        if: ${{ failure() }}
        shell: bash
        run: ./util/print_surefire_reports.sh
      - name: 'Set up Gradle'

# Tutorial - User Guide { #tutorial-user-guide }

This tutorial shows you how to use **FastAPI** with most of its features, step by step.

Each section gradually builds on the previous ones, but it's structured to separate topics, so that you can go directly to any specific one to solve your specific API needs.

It is also built to work as a future reference so you can come back and see exactly what you need.

## Run the code { #run-the-code }

    ///

    The `--upgrade` option tells `pip` to upgrade the packages if they are already installed.

    Because the previous step copying the file could be detected by the **Docker cache**, this step will also **use the Docker cache** when available.

It is easy to assume that HTTPS is something that is just "enabled" or not.

But it is way more complex than that.

/// tip

If you are in a hurry or don't care, continue with the next sections for step by step instructions to set everything up with different techniques.

///

    init: GradleBuildStep.() -> Unit,
    custom: GradleBuildStep.() -> Unit,
): GradleBuildStep =
    GradleBuildStep(init)
        .apply(custom)
        .also {
            step(it)
        }

/**
 * Adds a [Gradle build step](https://confluence.jetbrains.com/display/TCDL/Gradle)
 * that runs with the Gradle wrapper.
 *
 * @see GradleBuildStep
 */
fun BuildSteps.gradleWrapper(
    buildType: BuildType? = null,

This could be useful if for example you live in a country that restricts some URLs.

### Disable the automatic docs { #disable-the-automatic-docs }

The first step is to disable the automatic docs, as by default, those use the default CDN.

To disable them, set their URLs to `None` when creating your `FastAPI` app:

{* ../../docs_src/custom_docs_ui/tutorial001.py hl[8] *}

In an advanced scenario where you know you need the dependency to be called at every step (possibly multiple times) in the same request instead of using the "cached" value, you can set the parameter `use_cache=False` when using `Depends`:

//// tab | Python 3.8+

```Python hl_lines="1"

		//    successfully acquiring the lock.
		// 2) lk2 then needs to advance and remove the resource from lockMap.
		// 3) lk3 or lk4 (whichever didn't execute in step 1) then executes and creates
		//    a new entry in lockMap and acquires a lock for the same resource.

		<-lk2ch
		lk3ok := <-lk3ch
		lk4ok := <-lk4ch

		if lk3ok && lk4ok {