lwmqn-util

lwmqn-util

Utility for LWMQN MQTT-Shepherd and MQTT-Node

Table of Contents

1. Overiew
2. Installation
3. APIs
   

1. Overview

lwmqn-util is a utility for Lightweight Mqtt Machine Network (LWMQN) Server and Client modules. This utility provides some common methods of getting identifiers in string or in number, getting command ids, getting response codes, and tackling the path of resource alloaction.

2. Installation

$ npm install lwmqn-util --save

3. APIs

• .getOid()
• .oidKey()
• .oidNum()
• .getRid()
• .ridKey()
• .ridNum()
• .getRspCode()
• .rspCodeKey()
• .rspCodeNum()
• .getCmd()
• .cmdKey()
• .cmdNum()
• .createPath()
• .slashPath()
• .dotPath()
• .pathItems()
• .buildPathValuePairs()
• .isGoodResponse()
• .getAccessCtrl()
• .jsonify()

---

.getOid(oid)

Returns an item of the Object identifier.

Arguments

• oid (String | Number): oid can be given with a string or a number. Notice that a numbered string will be recognized as a number, e.g. '128' is equal to 128.

Returns:

• (Object | Undefined) Returns an item of { key: 'sampleId', value: 1234 }, otherwise returns undefined if not found.

Example

var ut = require('lwmqn-util');

ut.getOid('temperature');  // { key: 'temperature', value: 3303 }
ut.getOid(3303);           // { key: 'temperature', value: 3303 }
ut.getOid('3303');         // { key: 'temperature', value: 3303 }

ut.getOid('xxxx');         // undefined 
ut.getOid('9999');         // undefined 
ut.getOid(9999);           // undefined 

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.oidKey(oid)

Returns the string of an Object identifier.

Arguments

• oid (String | Number): oid can be given with a string or a number. Notice that a numbered string will be recognized as a number, e.g. '128' is equal to 128.

Returns:

• (String) Returns the id string, otherwise returns the argument 'oid' ifself if not found.

Example

ut.oidKey('temperature');  // 'temperature'
ut.oidKey(3303);           // 'temperature'
ut.oidKey('3303');         // 'temperature'

ut.oidKey('xxxx');         // 'xxxx' (returns the argument itself if id not found)
ut.oidKey('9999');         // '9999'
ut.oidKey(9999);           // 9999

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.oidNum(oid)

Returns the number of an Object identifier.

Arguments

• oid (String | Number): oid can be given with a string or a number. Notice that a numbered string will be recognized as a number, e.g. '128' is equal to 128.

Returns:

• (Number) Returns the id number, otherwise returns the argument 'oid' ifself if not found.

Example

ut.oidNum('temperature');  // 3303
ut.oidNum(3303);           // 3303
ut.oidNum('3303');         // 3303

ut.oidKey('xxxx');         // 'xxxx' (returns the argument itself if id not found)
ut.oidKey('9999');         // 9999
ut.oidKey(9999);           // 9999

---

.getRid([oid,] rid)

Returns an item of the Resource identifier.
To query a Resource id specific to an Object, both oid and rid should be given.
To query an unique Resource id, only the single argument rid is needed.

Arguments

• oid (String | Number, optional): oid can be given with a string or a number. Notice that a numbered string will be recognized as a number, e.g. '128' is equal to 128.
• rid (String | Number): rid can be given with a string or a number. Notice that a numbered string will be recognized as a number, e.g. '128' is equal to 128.

Returns:

• (Object | Undefined) Returns an item of { key: 'sampleId', value: 1234 }, otherwise returns undefined if not found.

Example

// get a Resource id specific to an Object
ut.getRid('location', 'lon');             // { key: 'lon', value: 1 }
ut.getRid(6, 1);                          // { key: 'lon', value: 1 }
ut.getRid('temperature', 'sensorValue');  // { key: 'sensorValue', value: 5700 }
ut.getRid(3303, 5700);                    // { key: 'sensorValue', value: 5700 }
ut.getRid('temperature', '5700');         // { key: 'sensorValue', value: 5700 }

// get an unqiue Resource id
ut.getRid('appType');                     // { key: 'appType', value: 5750 }
ut.getRid(5750);                          // { key: 'appType', value: 5700 }
ut.getRid('5750');                        // { key: 'appType', value: 5750 }

---

.ridKey([oid ,] rid)

Returns the string of an Resource identifier.

Arguments

• oid (String | Number, optional): oid can be given with a string or a number. Notice that a numbered string will be recognized as a number, e.g. '128' is equal to 128.
• rid (String | Number): rid can be given with a string or a number. Notice that a numbered string will be recognized as a number, e.g. '128' is equal to 128.

Returns:

• (String) Returns the Resource id in string, otherwise returns the argument 'rid' ifself if not found.

Example

// get a Resource id specific to an Object
ut.ridKey('location', 'lon');             // 'lon'
ut.ridKey(6, 1);                          // 'lon'
ut.ridKey('temperature', 'sensorValue');  // 'sensorValue'
ut.ridKey(3303, 5700);                    // 'sensorValue'
ut.ridKey('temperature', '5700');         // 'sensorValue'

// get an unqiue Resource id
ut.ridKey('appType');                     // 'appType'
ut.ridKey(5750);                          // 'appType'
ut.ridKey('5750');                        // 'appType'

// returns rid itself if not found
ut.ridKey('no_such_rid');                  // 'no_such_rid'
ut.ridKey(3303, 'no_such_id');             // 'no_such_id'

---

.ridNum([oid ,] rid)

Returns the number of an Resource identifier.

Arguments

• oid (String | Number, optional): oid can be given with a string or a number. Notice that a numbered string will be recognized as a number, e.g. '128' is equal to 128.
• rid (String | Number): rid can be given with a string or a number. Notice that a numbered string will be recognized as a number, e.g. '128' is equal to 128.

Returns:

• (Number) Returns the Resource id in number, otherwise returns the argument 'rid' ifself if not found.

Example

// get a Resource id specific to an Object
ut.ridNum('location', 'lon');             // 1
ut.ridNum(6, 1);                          // 1
ut.ridNum('temperature', 'sensorValue');  // 5700
ut.ridNum(3303, 5700);                    // 5700
ut.ridNum('temperature', '5700');         // 5700

// get an unqiue Resource id
ut.ridNum('appType');                     // 5750
ut.ridNum(5750);                          // 5750
ut.ridNum('5750');                        // 5750

// returns rid itself if not found
ut.ridNum('no_such_rid');                  // 'no_such_rid'
ut.ridNum('99999');                        // 99999 (no such rid)
ut.ridNum(99999);                          // 99999 (no such rid)
ut.ridNum(3303, 7654);                     // 7654  (no such rid)

---

.getRspCode(code)

Returns an item of the Response code.

Arguments

• code (String | Number): code can be given with a string or a number.

Returns:

• (Object | Undefined) Returns an item in the form of { key: 'Created', value: 201 }, otherwise returns undefined if not found.

Example

ut.getRspCode('BadRequest');  // { key: 'BadRequest', value: 400 }
ut.getRspCode(400);           // { key: 'BadRequest', value: 400 }
ut.getRspCode(302);           // undefined 

---

.rspCodeKey(code)

Returns the string of an Response code.

Arguments

• code (String | Number): code can be given with a string or a number.

Returns:

• (String | Undefined) Returns the string of an Response code, otherwise returns undefined if not found.

Example

ut.rspCodeKey('BadRequest');  // 'BadRequest'
ut.rspCodeKey(400);           // 'BadRequest'
ut.rspCodeKey(302);           // undefined 

---

.rspCodeNum(code)

Returns the number of an Response code.

Arguments

• code (String | Number): code can be given with a string or a number.

Returns:

• (Number | Undefined) Returns the number of an Response code, otherwise returns undefined if not found.

Example

ut.rspCodeKey('BadRequest');  // 400
ut.rspCodeKey(400);           // 400
ut.rspCodeKey(302);           // undefined 

---

.getCmd(cmd)

Returns an item of the command idetifier.

Arguments

• code (String | Number): cmd can be given with a string or a number.

Returns:

• (Object | Undefined) Returns an item in the form of { key: 'discover', value: 2 }, otherwise returns undefined if not found.

Example

ut.getCmd('read');          // { key: 'read', value: 0 }
ut.getCmd('write');         // { key: 'write', value: 1 }
ut.getCmd('discover');      // { key: 'discover', value: 2 }
ut.getCmd('writeAttrs');    // { key: 'writeAttrs', value: 3 }
ut.getCmd('execute');       // { key: 'execute', value: 4 }
ut.getCmd('observe');       // { key: 'observe', value: 5 }
ut.getCmd('notify');        // { key: 'execute', value: 6 }

ut.getCmd(0);   // { key: 'read', value: 0 }
ut.getCmd(1);   // { key: 'write', value: 1 }
ut.getCmd(2);   // { key: 'discover', value: 2 }
ut.getCmd(3);   // { key: 'writeAttrs', value: 3 }
ut.getCmd(4);   // { key: 'execute', value: 4 }
ut.getCmd(5);   // { key: 'observe', value: 5 }
ut.getCmd(6);   // { key: 'execute', value: 6 }

---

.cmdKey(cmd)

Returns the string of an command identifier.

Arguments

• code (String | Number): cmd can be given with a string or a number.

Returns:

• (String | Undefined) Returns the string of an command id, otherwise returns undefined if unrecognized.

Example

ut.cmdKey('read');        // 'read'
ut.cmdKey(4);             // 'execute'
ut.cmdKey('no_such_cmd'); // undefined 
ut.cmdKey(22);            // undefined 

---

.cmdNum(cmd)

Returns the number of an command identifier.

Arguments

• code (String | Number): cmd can be given with a string or a number.

Returns:

• (Number | Undefined) Returns the number of an command id, otherwise returns undefined if unrecognized.

Example

ut.cmdKey('read');        // 0
ut.cmdKey(4);             // 4
ut.cmdKey('no_such_cmd'); // undefined 
ut.cmdKey(22);            // undefined 

---

.createPath(cnnt, ...)

Returns a path string in conjunction of the given connector.

Arguments

• cnt (String|Number): The connector, can be '.' or '/'
• ... (String, variadic): Words to be connected

Returns:

• (String) Returns the combined result.

Example

ut.createPath('.', 'dev', 0, 'sensor');          // 'dev.0.sensor'
ut.createPath('/', 'dev', 0, 'sensor', 'value'); // 'dev/0/sensor/value'

---

.slashPath(path)

Returns a path with '/' separator.

Arguments

• path (String): The path string

Returns:

• (String) Returns the result. The first and last character will be ignored if they are '.' or '/'.

Example

ut.slashPath('dev.0.sensor.value');     // 'dev/0/sensor/value'
ut.slashPath('.dev.0.sensor.value');    // 'dev/0/sensor/value'
ut.slashPath('/dev.0.sensor/value/');   // 'dev/0/sensor/value'
ut.slashPath('/dev/0/sensor/value/');   // 'dev/0/sensor/value'

---

.dotPath(path)

Returns a path with '.' separator.

Arguments

• path (String): The path string

Returns:

• (String) Returns the result. The first and last character will be ignored if they are '.' or '/'.

Example

ut.dotPath('dev.0.sensor.value');     // 'dev.0.sensor.value'
ut.dotPath('.dev.0.sensor.value');    // 'dev.0.sensor.value'
ut.dotPath('/dev.0.sensor/value/');   // 'dev.0.sensor.value'
ut.dotPath('/dev/0/sensor/value/');   // 'dev.0.sensor.value'

---

.pathItems(path)

Returns an array of words that are separated by '.' or '/'.

Arguments

• path (String): The path string

Returns:

• (Array) Returns the words in an array.

Example

ut.pathItems('dev.0.sensor.value');     // [ 'dev', '0', 'sensor', 'value' ]
ut.pathItems('.dev.0.sensor.value');    // [ 'dev', '0', 'sensor', 'value' ]
ut.pathItems('/dev.0.sensor/value/');   // [ 'dev', '0', 'sensor', 'value' ]
ut.pathItems('/dev/0/sensor/value/');   // [ 'dev', '0', 'sensor', 'value' ]

---

.buildPathValuePairs(rootPath, obj)

Returns an object in path-value pair.

Arguments

• rootPath (String): The path where the obj attachs to
• obj (Object): The object to be built from

Returns:

• (Object) Returns a new object that is orginized in path-vale pair.

Example

var myObj = {
    a: {
        a1: {
            a11: 1,
            a12: 'hi',
        },
        a2: 'foo'
    },
    b: 'hello',
    c: 3
};

var newObj = ut.buildPathValuePairs('/', myObj);
// newObj = {
//     'a.a1.a11': 1,
//     'a.a1.a12': 'hi',
//     'a.a2': 'foo',
//     'b': 'hello',
//     'c': 3
// }

var newObj = ut.buildPathValuePairs('/dev/0', myObj);
// newObj = {
//     'dev.0.a.a1.a11': 1,
//     'dev.0.a.a1.a12': 'hi',
//     'dev.0.a.a2': 'foo',
//     'dev.0.b': 'hello',
//     'dev.0.c': 3
// }

---

.isGoodResponse(status)

Check if a status code is a good response. The good responses are those with status codes in either one of 200, 201, 202, 204, and 205.

Arguments

• status (String | Number): status can be given with a string or a number.

Returns:

• (Boolean) Returns true if status is a good response, otherwise returns false.

Example

ut.isGoodResponse(200);         // true
ut.isGoodResponse('Deleted');   // true
ut.isGoodResponse('NotFound');  // false
ut.isGoodResponse(409);         // false

---

.getAccessCtrl()

Get the access control flag of an Resource. Please refer to lwm2m-id documentation.

Arguments

• oid (String | Number, optional): oid can be given with a string or a number. Notice that a numbered string will be recognized as a number, e.g. '128' is equal to 128.
• rid (String | Number): rid can be given with a string or a number. Notice that a numbered string will be recognized as a number, e.g. '128' is equal to 128.

Returns:

• (String | Null | Undefined) Returns the access control flag which can be 'R' (read-only), 'W' (write-only), 'RW', 'E' (executable), and null (cannot access). Returns undfined if the Resource is not found.

Example

ut.getAccessCtrl('temperature', 'sensorValue'); // 'R'
ut.getAccessCtrl('lightCtrl', 5850);            // 'RW'
ut.getAccessCtrl('xxxx', 1234);                 // undfined

---

.jsonify(str)

Jsonify a string into a Javascript object.

Arguments

• str (String): The string to be jsonified.

Returns:

• (Object | String) Returns an object if the string can be jsonified, otherwise returns the string itself.

Example

ut.jsonify('{"x": 3, "y": 'hi'}');  // { x: 3, y: 'hi' }
ut.jsonify('hello there');          // 'hello there'

---