Return of the COAP and IoT system Json__json

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 command-line toolset. COAP Client code example

Before we start we need to have a client 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/');
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 ();

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

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

In that case, we only need to judge at the end of our service,

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

This will allow you to return the data. (Reprint reservation: COAP and IoT system returns JSON) COAP server-side code

The server side of the code is relatively simple, to determine

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 returns a 205, which is the content, only when the design is to request a URL to return the corresponding data. Such as

coap://localhost/id/1/

The data that should be requested is ID 1, 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's all displayed, and it's a bit of a bad design, but it's almost there now.