{* ../../docs_src/first_steps/tutorial001_py310.py hl[3] *}

這裡的 `app` 變數將會是 `FastAPI` 類別的「實例」。

這將是你建立所有 API 的主要互動點。

### 第三步：建立一個「路徑操作」 { #step-3-create-a-path-operation }

#### 路徑 { #path }

這裡的「路徑」指的是 URL 中自第一個 `/` 以後的部分。

例如，在 URL 中：

```
https://example.com/items/foo
```

……的路徑將會是：

```
/items/foo
```

/// info

    synchronized void insert(final String path, final DfsReferral dr) {
        int s1, s2;
        String server, share, key;

        if (DISABLED) {
            return;
        }

        s1 = path.indexOf('\\', 1);
        s2 = path.indexOf('\\', s1 + 1);
        server = path.substring(1, s1);
        share = path.substring(s1 + 1, s2);

        key = path.substring(0, dr.pathConsumed).toLowerCase();

        // Assert cause propagation
        assertSame(mockCause, ex.getCause(), "Cause should be exactly the provided instance");

        // Access common Throwable methods to exercise paths without touching the cause
        assertNotNull(ex.toString(), "toString should be non-null");
        ex.getMessage(); // don't assert content to avoid implementation assumptions

                    + proximity + ",ttl=" + ttl + ",pathOffset=" + pathOffset + ",altPathOffset=" + altPathOffset + ",nodeOffset="
                    + nodeOffset + ",path=" + path + ",altPath=" + altPath + ",node=" + node + "]");
        }
    }

    int pathConsumed;
    int numReferrals;
    int flags;
    Referral[] referrals;

    Trans2GetDfsReferralResponse() {

            str = str.substring(1, length - 1);
        }
        return str;
    }

    @Nonnull
    public static Path getCanonicalPath(Path path) {
        requireNonNull(path, "path");
        return path.toAbsolutePath().normalize();
    }

    @Nonnull
    public static Map<String, String> toMap(Properties properties) {
        requireNonNull(properties, "properties");

    * Pero te proporciona las herramientas para construir aplicaciones web sencillas, con enrutamiento basado en paths, etc.
    * Si estás comparando Starlette, compáralo con Sanic, Flask, Django, etc. Frameworks web (o microframeworks).
* **FastAPI**:

# in compliance with, at your election, the Elastic License 2.0 or the Server
# Side Public License, v 1.

java.nio.file.Paths @ Use org.elasticsearch.core.PathUtils.get() instead.
java.nio.file.Path#of(java.net.URI) @ Use org.elasticsearch.core.PathUtils.get() instead.
java.nio.file.Path#of(java.lang.String, java.lang.String[]) @ Use org.elasticsearch.core.PathUtils.get() instead.

  JAVA_CLASS_VERSION("java.class.version"),

  /** Java class path. */
  JAVA_CLASS_PATH("java.class.path"),

  /** List of paths to search when loading libraries. */
  JAVA_LIBRARY_PATH("java.library.path"),

  /** Default temp file path. */
  JAVA_IO_TMPDIR("java.io.tmpdir"),

  /** Name of JIT compiler to use. */
  JAVA_COMPILER("java.compiler"),

  /**
   * Path of extension directory or directories.
   *

     *
     * @return the transport pool
     */
    SmbTransportPool getTransportPool();

    /**
     * Get the DFS resolver for handling distributed file system paths
     *
     * @return the DFS instance for this context
     */
    DfsResolver getDfs();

    /**
     * Get the SID resolver for resolving security identifiers
     *

    public BuildEventListener buildEventListener;

    // paths user can override from CLI, and we need to set on MavenExReq
    public Path installationSettingsPath;
    public Path projectSettingsPath;
    public Path userSettingsPath;
    public boolean interactive;
    public Path localRepositoryPath;
    public Settings effectiveSettings;
    public PersistedToolchains effectiveToolchains;