Coap and the return JSON of the IoT system

After adding JSON support to IoT Coap, it becomes very interesting, at least we can get the results we want. In the previous article we introduced some common tools--coap the command-line toolset.

COAP Client code example

Before we start we need to have a client-side code so that our server can return the correct data and parse

var coap = require (' Coap '); var requesturi = ' coap://localhost/'; var url = require (' URL '). Parse (RequestUri + ' id/1/'); cons Ole.log ("Request URL:" + url.href), var req = coap.request (URL), var bl = require (' bl '); Req.setheader ("Accept", "Applicati On/json "); Req.on (' Response ', function (res) {    res.pipe (BL (function (err, data) {        var json = json.parse (data);        Console.log (JSON);    });}); Req.end ();

The code is a bit too long, but the core is this sentence:

Req.setheader ("Accept", "Application/json");

In that case, we only need to judge on our service side,

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

This will return the data. (Reprint reservation: Coap and the return JSON of the Internet of Things system)

CoAP Server-side code

Server-side code is relatively simple, judge

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

Whether the request is in JSON format, and then returns a 205, which is the content, just then the design is to request a URL to return the corresponding data. Such as

coap://localhost/id/1/

At this point, the data with ID 1 should be requested, i.e.

[{id:1, Value: ' Is ID 1 ', sensors1:19, sensors2:20}]

and Parse_url just reads the corresponding data from the database.

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))}    )}

and it all shows up, it's a bit of a design, but it's almost there.