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@sporto
Last active December 10, 2019 16:58
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Concurrency: JavaScript vs Go
package main
import (
"fmt"
"io/ioutil"
"net/http"
"os"
"time"
)
var baseUrl string = "http://localhost:8080"
func exitOnError(err error) {
if err != nil {
fmt.Println("%s", err)
os.Exit(1)
}
}
func getValue(url string, c chan string) error {
fmt.Println("Getting " + url)
res, err := http.Get(baseUrl + url)
exitOnError(err)
defer res.Body.Close()
body, err := ioutil.ReadAll(res.Body)
exitOnError(err)
s := string(body)
fmt.Println("Result => ", s)
c <- s
return nil
}
func processConcat(x string, y string) (string, error) {
res, err := http.Get(baseUrl + "/concat?x=" + x + "&y=" + y)
exitOnError(err)
defer res.Body.Close()
body, err := ioutil.ReadAll(res.Body)
exitOnError(err)
s := string(body)
fmt.Println("Result from concat => ", s)
return s, nil
}
func main() {
startTime := time.Now()
var cx chan string = make(chan string)
var cy chan string = make(chan string)
go getValue("/x", cx)
go getValue("/y", cy)
x := <-cx
y := <-cy
processConcat(x, y)
endTime := time.Now()
fmt.Println("ElapsedTime in seconds:", endTime.Sub(startTime))
os.Exit(0)
}
var request = require('request');
var Q = require('q');
var startTime = process.hrtime();
var defX = Q.defer();
var defY = Q.defer();
var oneAndTwo = Q.all([defX.promise, defY.promise]).then(processConcat);
var baseUrl = "http://localhost:8080";
request(baseUrl + '/x', makeValueHandler(defX));
request(baseUrl + '/y', makeValueHandler(defY));
function makeValueHandler(def) {
return function (error, response, body) {
if (!error && response.statusCode == 200) {
console.log('Result from', body);
def.resolve(body);
} else {
console.log(error);
def.reject(error);
}
}
}
function processConcat(res) {
//console.log('combined results', res);
var url = baseUrl + "/concat?x=" + res[0] + "&y=" + res[1];
//console.log(url);
request(url, function (error, response, body) {
if (!error && response.statusCode == 200) {
console.log('Result from concat => ', body);
} else {
console.log("Error");
}
printElapsedTime();
});
}
function printElapsedTime() {
var precision = 3; // 3 decimal places
var elapsed = process.hrtime(startTime);
console.log('ElapsedTime in seconds: %d.%d', elapsed[0], elapsed[1]);
}
var http = require('http');
var url = require('url');
var requestListener = function (request, response) {
var url_parts = url.parse(request.url, true);
var path = url_parts.pathname;
var query = url_parts.query;
switch(path) {
case '/concat':
var x = url_parts.query.x;
var y = url_parts.query.y;
respondWith(x + " " + y, 1000);
break;
case '/x':
respondWith("Hello", 2500);
break;
case '/y':
respondWith("World", 1400);
break;
default:
response.writeHead(404);
response.end();
}
function respondWith(body, delay) {
setTimeout(function () {
response.writeHead(200);
response.end(body);
}, delay);
}
}
var server = http.createServer(requestListener);
server.listen(8080);
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