func checkResult(result, expected string) error {
	resultFile, err := os.ReadFile(result)
	if err != nil {
		return fmt.Errorf("couldn't read result: %v", err)
	}
	expectedFile, err := os.ReadFile(expected)
	if err != nil {
		return fmt.Errorf("couldn't read expected: %v", err)
	}
	if !bytes.Equal(resultFile, expectedFile) {

                ),
                "description": "Production environment",
            },
        ],
        "paths": {
            "/app": {
                "get": {
                    "summary": "Read Main",
                    "operationId": "read_main_app_get",
                    "responses": {
                        "200": {
                            "description": "Successful Response",

                            bufDataStart + dataDisplacement, dataCount );
            bufferIndex += dataCount;
        }

        /* Check to see if the entire transaction has been
         * read. If so call the read methods.
         */

        if( !parametersDone &&
                ( parameterDisplacement + parameterCount ) == totalParameterCount) {
            parametersDone = true;
        }

# Advanced Middleware

In the main tutorial you read how to add [Custom Middleware](../tutorial/middleware.md){.internal-link target=_blank} to your application.

And then you also read how to handle [CORS with the `CORSMiddleware`](../tutorial/cors.md){.internal-link target=_blank}.

In this section we'll see how to use other middlewares.

## Adding ASGI middlewares

				}
			}
			refDec := json.NewReader(io.NopCloser(bytes.NewBuffer(ref)), &json.ReaderArgs{ContentType: "json"})

			for {
				rec, err := dec.Read(nil)
				if err == io.EOF {
					break
				}
				if err != nil {
					t.Error(err)
				}
				want, err := refDec.Read(nil)
				if err != nil {
					t.Error(err)
				}
				var gotB, wantB bytes.Buffer
				opts := sql.WriteCSVOpts{
					FieldDelimiter: ',',

In some cases, you may want to override the logic used by the `Request` and `APIRoute` classes.

In particular, this may be a good alternative to logic in a middleware.

For example, if you want to read or manipulate the request body before it is processed by your application.

/// danger

This is an "advanced" feature.

If you are just starting with **FastAPI** you might want to skip this section.

///

                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        }
                    },
                    "summary": "Read Items",
                    "operationId": "read_items_items__get",
                    "security": [{"OAuth2PasswordBearer": []}],
                }
            }
        },
        "components": {

                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        }
                    },
                    "summary": "Read Current User",
                    "operationId": "read_current_user_users_me_get",
                    "security": [{"OpenIdConnect": []}],
                }
            }
        },
        "components": {

                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        }
                    },
                    "summary": "Read Current User",
                    "operationId": "read_current_user_users_me_get",
                    "security": [{"OpenIdConnect": []}],
                }
            }
        },
        "components": {

                            "description": "Successful Response",
                            "content": {"application/json": {"schema": {}}},
                        }
                    },
                    "summary": "Read Items",
                    "operationId": "read_items_items__get",
                }
            }
        },