/// tip

When writing the code to document a callback, it might be useful to imagine that you are that *external developer*. And that you are currently implementing the *external API*, not *your API*.

Temporarily adopting this point of view (of the *external developer*) can help you feel like it's more obvious where to put the parameters, the Pydantic model for the body, for the response, etc. for that *external API*.

///

### Create a callback `APIRouter`

	addr = u.Host
	scheme = u.Scheme

	// Use the given parameter again if url.Parse()
	// didn't return any useful result.
	if addr == "" {
		addr = hostAddr
		scheme = "http"
	}

	// At this point, addr can be one of the following form:
	//	":9000"
	//	"localhost:9000"
	//	"localhost" <- in this case, we check for scheme

	host, port, err := net.SplitHostPort(addr)
	if err != nil {

	b.lastRead = opInvalid
	m, ok := b.tryGrowByReslice(1)
	if !ok {
		m = b.grow(1)
	}
	b.buf[m] = c
	return nil
}

// WriteRune appends the UTF-8 encoding of Unicode code point r to the
// buffer, returning its length and an error, which is always nil but is
// included to match [bufio.Writer]'s WriteRune. The buffer is grown as needed;
// if it becomes too large, WriteRune will panic with [ErrTooLarge].

                {
                    "name": "Bar",
                    "price": "35.4",
                },
                {
                    "name": "Baz",
                    "price": "thirty five point four",
                },
            ],
        ),
    ],
):
    results = {"item_id": item_id, "item": item}

                {
                    "name": "Bar",
                    "price": "35.4",
                },
                {
                    "name": "Baz",
                    "price": "thirty five point four",
                },
            ],
        ),
    ],
):
    results = {"item_id": item_id, "item": item}

org.slf4j.simpleLogger.cacheOutputStream=true
org.slf4j.simpleLogger.levelInBrackets=true
org.slf4j.simpleLogger.log.Sisu=info
org.slf4j.simpleLogger.warnLevelString=WARNING

# MNG-6181: mvn -X also prints all debug logging from HttpClient
org.slf4j.simpleLogger.log.org.apache.http=off

	}

	doubleAgeRes := &result{}
	if err := DB.Table("users").Select("age + age as age").Where("id = ?", user3.ID).Scan(&doubleAgeRes).Error; err != nil {
		t.Errorf("Scan to pointer of pointer")
	}

	if doubleAgeRes.Age != int(res.Age)*2 {
		t.Errorf("Scan double age as age, expect: %v, got %v", res.Age*2, doubleAgeRes.Age)
	}

	var results []result

```sh
ufw allow 9000
```

Below command enables all incoming traffic to ports ranging from 9000 to 9010.

```sh
ufw allow 9000:9010/tcp
```

### firewall-cmd

For hosts with firewall-cmd enabled (CentOS), you can use `firewall-cmd` command to allow traffic to specific ports. Use below commands to allow access to port 9000

//	{
//		outcode(int($1), &$2, 0, &$4);
//	}
label3:
	BLTZ	R1, 1(PC)
	BLTZ	R1, label3	// BLTZ R1, 85

//
// floating point conditional branch
//
//	LBRA rel
label4:
	BFPT	1(PC)
	BFPT	label4	// BFPT 87


	//
	// floating point operate
	//
	//	LFCONV freg ',' freg
	//	{
	//		outcode(int($1), &$2, 0, &$4);
	//	}
	ABSD	F1, F2

	//	LFADD freg ',' freg

# under the License.

# -----------------------------------------------------------------------------
# Apache Maven YourKit Profiler Startup Script
#
# Environment Variable Prerequisites
#
#   JAVA_HOME       Must point at your Java Development Kit installation.
#   MAVEN_OPTS      (Optional) Java runtime options used when Maven is executed.
#   MAVEN_SKIP_RC   (Optional) Flag to disable loading of mavenrc files.