17. RESTful的CoAP协议

• CoAP采用了二进制报头，而不是文本报头(text header)
• CoAP降低了头的可用选项的数量。
• CoAP减少了一些HTTP的方法
• CoAP可以支持检测装置

• CoAP-cli，一个基于NodeJS的CoAP命令行工具，其核心是基于Node-CoAP库。
• libcooap，一个用C写的CoAP命令行工具。
• Firefox Copper， 一个Firefox的插件。

 npm install coap-cli -g 

Commands:
get                    performs a GET request
put                    performs a PUT request
post                   performs a POST request
delete                 performs a DELETE request

coap get coap://vs0.inf.ethz.ch/
(2.05)  ************************************************************
I-D

coap get coap://iot-coap.phodal.com/id/1
(2.05)  [{"id":1,"value":"is id 1","sensors1":19,"sensors2":20}]

brew install libcoap

(1) 下载
git clone  https://github.com/authmillenon/libcoap.git
(2) 生成configure文件
autoconf
(3) 生成makefile文件
./configure
(4) 编译
make
(5) 安装
sudo make install 

coap-client 
coap-server

coap-server

coap-client -m get coap://localhost

v:1 t:0 tkl:0 c:1 id:37109
This is a test server made with libcoap (see http://libcoap.sf.net) 
Copyright (C) 2010--2013 Olaf Bergmann <bergmann@tzi.org>

1. 下载地址: https://addons.mozilla.org/en-US/firefox/addon/copper-270430/
2. 作为测试我们同样可以访问 coap://vs0.inf.ethz.ch:5683/

node-coap is a client and server library for CoAP modelled after the http module.

{
  "dependencies":{
    "coap": "0.7.2"
  }
}

npm install

sudo npm install

const coap = require('coap')
    , server  = coap.createServer()
server.on('request', function(req, res) {
  res.end('Hello ' + req.url.split('/')[1] + '\n')
})
server.listen(function() {
  console.log('server started')
})  

node app.js

const coap  = require('coap') 
    , req   = coap.request('coap://localhost/World')
req.on('response', function(res) {
  res.pipe(process.stdout)
})
req.end()

Hello World 

var DBHelper = require('./db_helper.js');
DBHelper.initDB();

function DBHelper(){
}
DBHelper.initDB = function(){};
module.exports = DBHelper;

var db = new sqlite3.Database(config["db_name"]);
var create_table = 'create table if not exists basic (' + config["db_table"] + ');';
db.serialize(function() {
    db.run(create_table);
    _.each(config["init_table"], function(insert_data) {
        db.run(insert_data);
    });
});
db.close();

config = {
    "db_name": "iot.db",
    "db_table": "id integer primary key, value text, sensors1 float, sensors2 float",
    "init_table":[
        "insert or replace into basic (id,value,sensors1,sensors2) VALUES (1, 'is id 1', 19, 20);",
        "insert or replace into basic (id,value,sensors1,sensors2) VALUES (2, 'is id 2', 20, 21);"
    ],
    "query_table":"select * from basic;"
};

DBHelper.urlQueryData = function (url, callback) {
    var db = new sqlite3.Database("iot.db");
    var result = [];
    console.log("SELECT * FROM basic where " + url.split('/')[1] + "=" + url.split('/')[2]);
    db.all("SELECT * FROM basic where " + url.split('/')[1] + "=" + url.split('/')[2], function(err, rows) {
        db.close();
        callback(JSON.stringify(rows));
    });
};

const coap       = require('coap')
     ,requestURI = 'coap://localhost/'
     ,url        = require('url').parse(requestURI + 'id/1/')
     ,req        = coap.request(url)
     ,bl         = require('bl');
req.setHeader("Accept", "application/json");
req.on('response', function(res) {
  res.pipe(bl(function(err, data) {
    var json = JSON.parse(data);
    console.log(json);
  }));
});
req.end();

coap://localhost/id/1/

var coap            = require('coap');
var server          = coap.createServer({});
var request_handler = require('./request_handler.js');
server.on('request', function(req, res) {
    switch(req.method){
        case "GET": request_handler.getHandler(req, res);
            break;
    }
});
server.listen(function() {
    console.log('server started');
});

request_helper.getHandler = function(req, res) {
    switch (req.headers['Accept']) {
        case "application/json":
            qh.returnJSON(req, res);
            break;
        case "application/xml":
            qh.returnXML(req, res);
            break;
    }
};

query_helper.returnJSON = function(req, res) {
    DBHelper.urlQueryData(req.url, function (result) {
        QueryData.returnJSON(result, res);
    });
};

DBHelper.urlQueryData = function (url, callback) {
    var db = new sqlite3.Database(config["db_name"]);
    console.log("SELECT * FROM basic where " + url.split('/')[1] + "=" + url.split('/')[2]);
    db.all("SELECT * FROM basic where " + url.split('/')[1] + "=" + url.split('/')[2], function(err, rows) {
        db.close();
        callback(JSON.stringify(rows));
    });
};

QueryData.returnJSON = function(result, res) {
    if (result.length == 2) {
        res.code = '4.04';
        res.end(JSON.stringify({
            error: "Not Found"
        }));
    } else {
        res.code = '2.05';
        res.end(result);
    }
};

• 温度传感器
• 灯光开关
• 楼宇自动化设备

const coap     = require('coap')
      ,request  = coap.request
      ,bl       = require('bl')
      ,req = request({hostname: 'localhost',port:5683,pathname: '',method: 'POST'});
req.setOption('Block2',  [new Buffer('1'),new Buffer("'must'"), new Buffer('23'), new Buffer('12')]);
req.setHeader("Accept", "application/json");
req.on('response', function(res) {
    res.pipe(bl(function(err, data) {
        console.log(data);
        process.exit(0);
    }));
});
req.end();

{ name: 'Block2', value: <Buffer 31> }
{ name: 'Block2', value: <Buffer 27 6d 75 73 74 27> }
{ name: 'Block2', value: <Buffer 32 33> }
{ name: 'Block2', value: <Buffer 31 32> }

_.values(e).toString()

_.values(e).toString().split(',')[1]

[ '1', '\'must\'', '23', '12' ]

互联网媒体类型是通过HTTP字符串标识，如“application/xml”。该字符串是由一个顶层的类型“applicaion”和子类型的“XML”。为了尽量减少使用这些类型的媒体类型来表示的开销消息有效载荷，COAP定义一个标识符编码方案互联网媒体类型的子集。预计这桌将可扩展标识符的值的IANA维护。内容类型选项被格式化为一个8位无符号整数。初始映射到一个合适的互联网媒体类型标识符表所示。复合型高层次类型（multipart和不支持消息）。标识符值是从201-255保留的特定于供应商的，应用程序特定的或实验使用和不由IANA。

request_helper.getHandler = function(req, res) {
    switch (req.headers['Accept']) {
        case "application/json":
            qh.returnJSON(req, res);
            break;
        case "application/xml":
            qh.returnXML(req, res);
            break;
    }
};

registerFormat('text/plain', 0)
registerFormat('application/link-format', 40)
registerFormat('application/xml', 41)
registerFormat('application/octet-stream', 42)
registerFormat('application/exi', 47)
registerFormat('application/json', 50)

req.setHeader("Accept", "application/json");

var coap = require('coap');
var requestURI = 'coap://localhost/';
var url = require('url').parse(requestURI + 'id/1/');
console.log("Request URL: " + url.href);
var req = coap.request(url);
var bl = require('bl');
req.setHeader("Accept", "application/json");
req.on('response', function(res) {
  res.pipe(bl(function(err, data) {
    var json = JSON.parse(data);
    console.log(json);
  }));
});
req.end();

req.setHeader("Accept", "application/json");

if(req.headers['Accept'] == 'application/json') {
     //do something
 };

if (req.headers['Accept'] == 'application/json') {
        parse_url(req.url, function(result){
            res.end(result);
        });
        res.code = '2.05';
    }

coap://localhost/id/1/

[ { id: 1, value: 'is id 1', sensors1: 19, sensors2: 20 }]

function parse_url(url ,callback) {
    var db = new sqlite3.Database(config["db_name"]);
    var result = [];
    db.all("SELECT * FROM basic;", function(err, rows) {
        callback(JSON.stringify(rows));
    })
}

npm install iot-coap

var iotcoap         = require('iot-coap');
iotcoap.run();
iotcoap.rest.run();

exports.config  = {
    "db_name": "iot.db",
    "mongodb_name": "iot",
    "mongodb_documents": "iot",
    "db": "mongodb",
    "table_name": "basic",
    "keys":[
        "id",
        "value",
        "sensors1",
        "sensors2"
    ],
    "db_table": "id integer primary key, value text, sensors1 float, sensors2 float",
    "mongodb_init":[
        {
            id: 1,
            value: "is id 1",
            sensors1: 19,
            sensors2: 20
        },
        {
            id: 2,
            value: "is id 2",
            sensors1: 20,
            sensors2: 21
        }
    ],
    "init_table":[
        "insert or replace into basic (id,value,sensors1,sensors2) VALUES (1, 'is id 1', 19, 20);",
        "insert or replace into basic (id,value,sensors1,sensors2) VALUES (2, 'is id 2', 20, 21);"
    ],
    "query_table":"select * from basic;",
    "rest_url": "/id/:id",
    "rest_post_url": "/",
    "rest_port": 8848
};

node index.js

coap listening at coap://0.0.0.0:5683
restify listening at http://0.0.0.0:8848