REST Client Samples
Created by Umoh Bassey-Duke
Overview
This page provides sample code for creating REST clients for various popular programming languages.
1. REST client code sample in JVM using JAVA
In this tutorial, we show how to create a RESTful Java client with Java built-in HTTP client library. It’s simple to use and good enough to perform basic operations for REST service.
Java client to send a “POST” request to PAGA getTransactionDetails method on the merchant restful API, with json string will be as simple as below.
REST Client
package restfulclient.main;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.security.MessageDigest;
public class RestClient {
public static void main(String[] args) {
try {
URL url = new URL("http://www.mypaga.com/paga-webservices/merchant-rest/getTransactionDetails");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("POST");
conn.setDoOutput(true);
conn.setRequestProperty("Content-Type", "application/json");
conn.setRequestProperty("principal", "AA6EEB78-BD92-4D0B-A87D-E3DB46C53B70"); //business organization publicId
conn.setRequestProperty("credentials", "password"); //business organization password
StringBuilder sBuilder = new StringBuilder();
sBuilder.append("09012939283"); //referenceNumber param value
sBuilder.append("0123"); //business organization api-key
conn.setRequestProperty("hash", RestClientTest.hashSHA512(sBuilder.toString(), 1000, true).toString());
//input should be the data formatted as a JSON.
String input = "{\"referenceNumber\":\"09012939283\"}";
OutputStream os = conn.getOutputStream();
os.write(input.getBytes());
os.close();
if (conn.getResponseCode() != 201 && conn.getResponseCode() != 200) {
throw new RuntimeException("Failed : HTTP error code : "
+ conn.getResponseCode());
}
BufferedReader br = new BufferedReader(new InputStreamReader(
(conn.getInputStream())));
String output;
System.out.println("Output from Server .... \n");
while ((output = br.readLine()) != null) {
System.out.println(output);
}
conn.disconnect();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
//hash sha-512 with some iterations
public static Object hashSHA512(String message, int iterations, boolean returnHex) {
try {
MessageDigest mda = MessageDigest.getInstance("SHA-512");
byte [] digest = mda.digest(message.getBytes());
for(int i = 0; i < iterations - 1; i++) {
digest = mda.digest(digest);
}
if(returnHex) {
return new String(Hex.encodeHex(digest));
} else {
return digest;
}
} catch(Exception e) {
return null;
}
}
}
On this page:
2. REST client code sample using PHP
PHP client to send a “POST” request to PAGA buy Airtime API, with json string will be as below.
PHP REST Client
<?php
$url = "http://www.mypaga.com/paga-webservices/merchant-rest/secured/getTransactionDetails";
$postdata = "{\"referenceNumber\":\"0012939283\"}";
//hash with sha-512 1000 times
//appended param values referenceNumber and merchant api key
$hash = hash('sha512', "0012939283"."0123");
for ($i=1; $i<1000; $i++) {
$hash = hash('sha512', pack("H*", $hash));
}
$opts = array(
"http" => array(
"method" => "POST",
"header" => "Content-Type: application/json\r\nprincipal: 757E1F82-C5C1-4883-B891-C888293F2F00\r\ncredentials: pa55w@rd \r\nhash:".$hash,
"content" => $postdata
)
);
$context = stream_context_create($opts);
$response = json_decode(file_get_contents($url, false, $context));
echo $result;
?>
3. REST client code sample in .NET using C#
.NET client to send a “POST” request to PAGA buy Airtime API, with json string will be as simple as below.
C# REST Client
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web;
using System.IO;
using System.Net;
namespace RESTfulClient
{
public class Program
{
public static void Main(string[] args)
{
// We use the HttpUtility class from the System.Web namespace
Uri address = new Uri("http://www.mypaga.com/paga-webservices/merchant-rest/registerCustomer");
// Create the web request
HttpWebRequest request = WebRequest.Create(address) as HttpWebRequest;
// Set type to POST
request.Method = "POST";
request.ContentType = "application/json";
request.Headers.Add("principal", "757E1F82-C5C1-4883-B891-C888293F2F00");
request.Headers.Add("credentials", "pa55w@rd");
//Get sha512 hash of the appended param values referenceNumber and api key with 1000 iterations
String hash = GetSha512("0012939283" + "0123", 1000);
//add hash header params
request.Headers.Add("hash", hash);
// Create the data we want to send
String data = "{\"referenceNumber\":\"0012939283\"}";
// Create a byte array of the data we want to send
byte[] byteData = UTF8Encoding.UTF8.GetBytes(data.ToString());
// Set the content length in the request headers
request.ContentLength = byteData.Length;
// Write data
using (Stream postStream = request.GetRequestStream())
{
postStream.Write(byteData, 0, byteData.Length);
}
// Get response
using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)
{
// Get the response stream
StreamReader reader = new StreamReader(response.GetResponseStream());
// Console application output
Console.WriteLine(reader.ReadToEnd());
}
}
//Get sha512 hash with certain iterations
public static String GetSha512(string text, long iterations)
{
string hash = "";
SHA512 alg = SHA512.Create();
byte[] result = alg.ComputeHash(Encoding.UTF8.GetBytes(text));
for (long i = 1; i < iterations - 1; i++)
{
result = alg.ComputeHash(result);
}
hash = BitConverter.ToString(result).Replace("-","");
return hash;
}
}
}