### Custom Generate Unique ID Function { #custom-generate-unique-id-function }

FastAPI uses a **unique ID** for each *path operation*, which is used for the **operation ID** and also for the names of any needed custom models, for requests or responses.

You can customize that function. It takes an `APIRoute` and outputs a string.

    private String id;
    /** The CSS class name to match */
    private String css;
    /** The custom attribute name to match */
    private String attrName;
    /** The custom attribute value to match */
    private String attrValue;

    /**
     * Creates a new PrunedTag instance with the specified tag name.
     *
     * @param tag the HTML tag name to match (e.g., "div", "span", "p")
     */

        "uid": "${DS_PROMETHEUS}"
      },
      "description": "",
      "fieldConfig": {
        "defaults": {
          "color": {
            "mode": "palette-classic"
          },
          "custom": {
            "axisBorderShow": false,
            "axisCenteredZero": false,
            "axisColorMode": "text",
            "axisLabel": "",
            "axisPlacement": "auto",
            "barAlignment": 0,

    - topic_repos: ../en/data/topic_repos.yml
  redirects:
    redirect_maps:
      deployment/deta.md: deployment/cloud.md
      advanced/graphql.md: how-to/graphql.md
      advanced/custom-request-and-route.md: how-to/custom-request-and-route.md
      advanced/conditional-openapi.md: how-to/conditional-openapi.md
      advanced/extending-openapi.md: how-to/extending-openapi.md

            }
        };

        assertEquals("Custom protocolType should be WEB", ProtocolType.WEB, customAnnotation.protocolType());
        assertEquals("Custom message should match", "Test message", customAnnotation.message());
        assertEquals("Custom groups should have one element", 1, customAnnotation.groups().length);
        assertEquals("Custom payload should have one element", 1, customAnnotation.payload().length);

                                                 title="Floating point number" required="required"
                                                 data-validation="custom"
                                                 data-validation-regexp="(\+|\-)?\d+(\.\d+)?((e|E)(\+|\-)?\d+)?"
                                                 data-validation-help="number (Float)"/>

{* ../../docs_src/middleware/tutorial001.py hl[8:9,11,14] *}

/// tip | Consejo

Ten en cuenta que los custom proprietary headers se pueden añadir <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">usando el prefijo 'X-'</a>.

        assertFalse(user.isEditable());
    }

    public void test_isEditable_custom() {
        // Test custom implementation that returns true
        FessUser user = new TestEditableFessUser("testuser", true);
        assertTrue(user.isEditable());

        // Test custom implementation that returns false
        user = new TestEditableFessUser("testuser", false);
        assertFalse(user.isEditable());

 * the symmetry of {@code equals}. Custom definitions of equality are usually based on an interface,
 * such as {@code Set} or {@code List}, so that the implementation of {@code equals} can cast the
 * object being tested for equality to the custom interface. {@code ForwardingObject} implements no
 * such custom interfaces directly; they are implemented only in subclasses. Therefore, forwarding

        // Verify that exception was handled
        assertTrue(exceptionHandled.get());
    }

    // Test with a custom ClassLoader to simulate class availability
    public void test_hook_withCustomClassLoader() throws Exception {
        // Create a custom ClassLoader that can control class loading behavior
        ClassLoader customClassLoader = new URLClassLoader(new URL[0], null) {
            @Override