How is an HTTP POST request made in node.js?

Question

How can I make an outbound HTTP POST request, with data, in node.js?

Answer 1

I found a video which explains on how to achieve this: https://www.youtube.com/watch?v=nuw48-u3Yrg

It uses default "http" module together with "querystring" and "stringbuilder" modules. The application takes two numbers (using two textboxes) from a web page and upon submit, returns sum of those two (along with persisting the values in the textboxes). This is the best example I could find anywhere else.

var http = require("http");
var qs = require("querystring");
var StringBuilder = require("stringbuilder");

var port = 9000;

function getCalcHtml(req, resp, data) {
    var sb = new StringBuilder({ newline: "\r\n" });
    sb.appendLine("");
    sb.appendLine(" ");
    sb.appendLine("     
");
    sb.appendLine("         ");
    sb.appendLine("             ");
    sb.appendLine("                 ");

    if (data && data.txtFirstNo) {
        sb.appendLine("                 ", data.txtFirstNo);
    }
    else {
        sb.appendLine("                 ");
    }

    sb.appendLine("             ");
    sb.appendLine("             ");
    sb.appendLine("                 ");

    if (data && data.txtSecondNo) {
        sb.appendLine("                 ", data.txtSecondNo);
    }
    else {
        sb.appendLine("                 ");
    }

    sb.appendLine("             ");
    sb.appendLine("             ");
    sb.appendLine("                 ");
    sb.appendLine("             ");

    if (data && data.txtFirstNo && data.txtSecondNo) {
        var sum = parseInt(data.txtFirstNo) + parseInt(data.txtSecondNo);
        sb.appendLine("             ");
        sb.appendLine("                 ", sum);
        sb.appendLine("             ");
    }

    sb.appendLine("         
Enter First No: 
Enter Second No: 
Sum: {0}
");
    sb.appendLine("     
")
    sb.appendLine(" ");
    sb.appendLine("");
    sb.build(function (err, result) {
        resp.write(result);
        resp.end();
    });
}

function getCalcForm(req, resp, data) {
    resp.writeHead(200, { "Content-Type": "text/html" });
    getCalcHtml(req, resp, data);
}

function getHome(req, resp) {
    resp.writeHead(200, { "Content-Type": "text/html" });
    resp.write("Want to some calculation? Click here");
    resp.end();
}

function get404(req, resp) {
    resp.writeHead(404, "Resource Not Found", { "Content-Type": "text/html" });
    resp.write("404: Resource not found. Go to Home");
    resp.end();
}

function get405(req, resp) {
    resp.writeHead(405, "Method not supported", { "Content-Type": "text/html" });
    resp.write("405: Method not supported");
    resp.end();
}

http.createServer(function (req, resp) {
    switch (req.method) {
        case "GET":
            if (req.url === "/") {
                getHome(req, resp);
            }
            else if (req.url === "/calc") {
                getCalcForm(req, resp);
            }
            else {
                get404(req, resp);
            }
            break;
        case "POST":
            if (req.url === "/calc") {
                var reqBody = '';
                req.on('data', function (data) {
                    reqBody += data;
                    if (reqBody.length > 1e7) { //10MB
                        resp.writeHead(413, 'Request Entity Too Large', { 'Content-Type': 'text/html' });
                        resp.end('413: Request Entity Too Large');
                    }
                });
                req.on('end', function () {
                    var formData = qs.parse(reqBody);
                    getCalcForm(req, resp, formData);
                });
            }
            else {
                get404(req, resp);
            }
            break;
        default:
            get405(req, resp);
            break;
    }
}).listen(port);