How to make something like remote method on loop-back middleware? - node.js

Question

In fallowing code i want to make something like remote method on middleware in loopback to post values to calculate for example:
in app :
submitForm() {
let headers = new Headers(
{
'Content-Type': 'application/json',
'Accept': 'application/json'
});
let options = new RequestOptions({ headers: headers });
let data = JSON.stringify({
Value1: this.form.value1,
Value2: this.form.value2,
Value3: this.form.value3
});
console.log(data);
let url = 'http://localhost:3000/calculate';
console.log(url);
return new Promise((resolve, reject) => {
this.http.post(url, data, options)
.toPromise()
.then((response) => {
console.log('API Response : ', response.status);
resolve(response.json());
})
.catch((error) => {
console.error('API Error : ', error.status);
console.error('API Error : ', JSON.stringify(error));
reject(error.json());
});
});
}
and in remote method or anything like that, I used such this code but totally fails:
module.exports = function () {
accepts: [{arg: 'val1', type: 'number'},{arg: 'val2', type: 'number'}],
returns: {arg: val1+val2, type: 'number'},
http: {path: '/calculate', verb: 'get'}
});
};

Answer 1

Example remote method that I used correctly
module.exports = function (TeamRole) {
TeamRole.getUsers = function (id, cb) {
TeamRole.find({
where: {
teamId: id
}
}, function (err, users) {
cb(null, users);
});
};
TeamRole.remoteMethod('getUsers', {
accepts: {
arg: "id",
type: "string",
required: true
},
returns: {
arg: 'users',
type: 'Array'
},
http: {
path: '/:id/users',
verb: 'get'
}
});
}
As above example you can define remote method correctly to achieve you task.
cheers.

Answer 2

This is my solution for my problem:
As you can see there is no parameters shown on URL and i think this may be secure I'm not expert one but I guess help to you:
module.exports = function(server) {
const https = require('https');
var request = require('request');
return function verification(req, res, next) {
res.setHeader('Access-Control-Allow-Origin', '*');
res.setHeader('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE');
res.setHeader('Access-Control-Allow-Headers', 'Content-Type');
res.setHeader('Access-Control-Allow-Credentials', true);
var request;
var response;
var body = '';
// When a chunk of data arrives.
req.on('data', function (chunk) {
// Append it.
body += chunk;
});
// When finished with data.
req.on('end', function () {
// Show what just arrived if POST.
if (req.method === 'POST') {
console.log(body);
}
// Which method?
switch (req.method) {
case 'GET':
Verify url and respond with appropriate data.
handleGet(req, res);
Response has already been sent.
response = '';
break;
case 'POST':
// Verify JSON request and respond with stringified JSON response.
response = handlePost(body);
break;
default:
response = JSON.stringify({ 'error': 'Not A POST' });
break;
}
// Send the response if not empty.
if (response.length !== 0) {
res.write(response);
res.end();
}
// Paranoid clear of the 'body'. Seems to work without
// this, but I don't trust it...
body = '';
});
// If error.
req.on('error', function (err) {
res.write(JSON.stringify({ 'error': err.message }));
res.end();
});
//
};
function handlePost(body) {
var response = '';
var obj = JSON.parse(body);
// Error if no 'fcn' property.
if (obj['fcn'] === 'undefined') {
return JSON.stringify({ 'error': 'Request method missing' });
}
// Which function.
switch (obj['fcn']) {
// Calculate() requres 3 arguments.
case 'verification':
// Error if no arguments.
if ((obj['arg'] === 'undefined') || (obj['arg'].length !== 3)) {
response = JSON.stringify({ 'error': 'Arguments missing' });
break;
}
// Return with response from method.
response = verification(obj['arg']);
break;
default:
response = JSON.stringify({ 'error': 'Unknown function' });
break;
}
return response;
};
function verification(arg) {
var n1 = Number(arg[0]);
var n2 = Number(arg[1]);
var n3 = Number(arg[2]);
var result;
// Addem up.
result = n1 + n2 + n3;
// Return with JSON string.
return JSON.stringify({ 'result': result });
};
};