Examples of calling an API HTTP GET for JSON in different languages

17 Feb 2019

Downloading JSON via GET from a simple API should be the 2nd tutorial right after Hello World for every language. Below is an ever-growing collection of code examples to highlight the differences in different programming languages and serve as a practical reference.

Jump to an implementation:

Contribution Rules/Guidelines

no 3rd party libraries/packages/modules allowed (unless required for HTTPS)
must be making an HTTPS request and use endpoint: https://swapi.co/api/people/1/
keep it simple and readable
its ok to ignore errors and best practices
when practical/terse include the code to parse JSON too

Please contribute (pull request) if you have a better approach or a new language.

Node.js HTTP GET

See https

var https = require('https');

var options = {
    host: 'swapi.co',
    path: '/api/people/1/',
    headers: {
        'Accept': 'application/json'
    }
};
https.get(options, function (res) {
    var json = '';

    res.on('data', function (chunk) {
        json += chunk;
    });

    res.on('end', function () {
        if (res.statusCode === 200) {
            try {
                var data = JSON.parse(json);
                // data is available here:
                console.log(json);
            } catch (e) {
                console.log('Error parsing JSON!');
            }
        } else {
            console.log('Status:', res.statusCode);
        }
    });
}).on('error', function (err) {
    console.log('Error:', err);
});

Javascript HTTP GET

Below is a sync example using XMLHttpRequest. From StackOverflow: HTTP GET request in JavaScript

  var req = new XMLHttpRequest();
  req.open('GET', 'https://swapi.co/api/people/1/', false);
  req.send(null);
  console.log(req.responseText);

Deno HTTP GET

Deno is a "simple, modern and secure runtime for JavaScript and TypeScript that uses V8 and is built in Rust."

You will need to use --allow-net to allow network access.

// Name the below go.ts
// Then run with: deno run --allow-net go.ts https://jsonplaceholder.typicode.com/todos/
const url = Deno.args[0];
const res = await fetch(url);
const items = await res.json();
console.log(items);

PHP HTTP GET

json_decode and filegetcontents. Source

$json = file_get_contents('https://swapi.co/api/people/1/');
echo $json;
$obj = json_decode($json);

Java HTTP GET

I don't know Java. Is this really the most simple way without 3rd party packages? Source

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;
import java.nio.charset.Charset;

import org.json.JSONException;
import org.json.JSONObject;

public class JsonReader {

  private static String readAll(Reader rd) throws IOException {
    StringBuilder sb = new StringBuilder();
    int cp;
    while ((cp = rd.read()) != -1) {
      sb.append((char) cp);
    }
    return sb.toString();
  }

  public static JSONObject readJsonFromUrl(String url) throws IOException, JSONException {
    InputStream is = new URL(url).openStream();
    try {
      BufferedReader rd = new BufferedReader(new InputStreamReader(is, Charset.forName("UTF-8")));
      String jsonText = readAll(rd);
      JSONObject json = new JSONObject(jsonText);
      return json;
    } finally {
      is.close();
    }
  }

  public static void main(String[] args) throws IOException, JSONException {
    JSONObject json = readJsonFromUrl("https://swapi.co/api/people/1/");
    System.out.println(json.toString());
    System.out.println(json.get("id"));
  }
}

Groovy HTTP GET

Apache Groovy is a Java-syntax-compatible object-oriented programming language for the Java platform. Source

def connection = new URL( "https://swapi.co/api/people/1/")
        .openConnection() as HttpURLConnection

connection.setRequestProperty( 'Accept', 'application/json' )

// get the response code - automatically sends the request
println connection.inputStream.text

C# HTTP GET

With WebClient. Code Source

using (WebClient wc = new System.Net.WebClient())
{
   var json = wc.DownloadString("https://swapi.co/api/people/1/");
}

or an async and HttpClient

using (var httpClient = new System.Net.Http.HttpClient())
{
    var json = await httpClient.GetStringAsync("https://swapi.co/api/people/1/");
}

Objective C and Cocoa HTTP GET

Source

// making a GET request to /init
NSString *targetUrl = @"https://swapi.co/api/people/1/";
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
[request setHTTPMethod:@"GET"];
[request setURL:[NSURL URLWithString:targetUrl]];

[[[NSURLSession sharedSession] dataTaskWithRequest:request completionHandler:
  ^(NSData * _Nullable data,
    NSURLResponse * _Nullable response,
    NSError * _Nullable error) {

      NSString *myString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
      NSLog(@"Data received: %@", myString);
}] resume];

Go programming language - Golang HTTP GET

Source

package main

import (
    "fmt"
    "net/http"
    "io/ioutil"
    "os"
    )

func main() {
    response, err := http.Get("https://swapi.co/api/people/1/")
    if err != nil {
        fmt.Printf("%s", err)
        os.Exit(1)
    } else {
        defer response.Body.Close()
        contents, err := ioutil.ReadAll(response.Body)
        if err != nil {
            fmt.Printf("%s", err)
            os.Exit(1)
        }
        fmt.Printf("%s\n", string(contents))
    }
}

Ruby HTTP GET

Source

require 'net/http'
require 'json'

url = 'https://swapi.co/api/people/1/'
uri = URI(url)
response = Net::HTTP.get(uri)
JSON.parse(response)

Python HTTP GET

Source

import requests
r = requests.get('https://swapi.co/api/people/1/')
r.json()

Tested with Python 2.7.12.

Perl HTTP GET

Source

#!/usr/bin/perl

 use LWP::UserAgent;
 use HTTP::Request;

 my $URL = 'https://swapi.co/api/people/1/';

 my $ua = LWP::UserAgent->new(ssl_opts => { verify_hostname => 1 });
 my $header = HTTP::Request->new(GET => $URL);
 my $request = HTTP::Request->new('GET', $URL, $header);
 my $response = $ua->request($request);

 if ($response->is_success){
     print "URL:$URL\nHeaders:\n";
     print $response->headers_as_string;
 }elsif ($response->is_error){
     print "Error:$URL\n";
     print $response->error_as_HTML;
 }

For http (non https) it can be simply be:

#!/usr/bin/perl
use LWP::Simple;
my $content = get('http://jsonplaceholder.typicode.com/todos/1');
print $content

Dart HTTP GET

Dart is "an object-oriented, class defined, garbage-collected language using a C-style syntax that transcompiles optionally into JavaScript." - Wikipedia. Code Source

import 'dart:io';
import 'dart:convert';

void main() {
  HttpClient()
    .getUrl(Uri.parse('https://swapi.co/api/people/1/')) // produces a request object
    .then((request) => request.close()) // sends the request
    .then((response) => response.transform(Utf8Decoder()).listen(print)); // transforms and prints the response
}

Swift HTTP GET

Swift is a "general-purpose, multi-paradigm, compiled programming language developed by Apple." -Wikipedia. Code Source.

let url = URL(string: "https://swapi.co/api/people/1/")!

let task = URLSession.shared.dataTask(with: url) {(data, response, error) in
    guard let data = data else { return }
    print(String(data: data, encoding: .utf8)!)
}

task.resume()

Rust

Rust is "a multi-paradigm systems programming language focused on safety, especially safe concurrency." - Wikipedia. Similar to C++.

Rust does not expose an http client?. You have to use hyper or reqwest. Does anyone know if its possible with just Rust?

Powershell (Windows) HTTP GET

Invoke-WebRequest "https://swapi.co/api/people/1/"

Shell (Bash etc) HTTP GET

curl "https://swapi.co/api/people/1/"
# or
curl -X GET -H "Accept: application/json" "https://swapi.co/api/people/1/"