$ curl --header "key:demo" -G --data-urlencode 'filter={"from":"Bob"}' https://beta.mrest.io/demo/messages?pagesize=2

[
    {
        "_id": {
            "$oid": "5b90101a198370e1dd7d0110"
        },
        "message": "was here",
        "from": "Bob",
        "timestamp": {
            "$date": 1536167962446
        }
    },
    {
        "_id": {
            "$oid": "5b49be10d418da78b75c3c2c"
        },
        "message": "RESTHeart rocks",
        "from": "Bob",
        "timestamp": {
            "$date": 1531559440350
        }
    }
]

const url = encodeURI('https://beta.mrest.io/demo/messages?filter={"from":"Bob"}&pagesize=2');

fetch(url, { headers: {'key':'demo'} })
  .then(response => response.json())
  .then(function(data) {
    console.log(JSON.stringify(data));
});

public void printOutMessages() throws UnirestException {
    HttpResponse<JsonNode> resp = Unirest.get("https://beta.mrest.io/demo/messages")
            .header("key", "demo")
            .queryString("filter", "{\"from\":\"Bob\"}")
            .queryString("pagesize", "2")
            .asJson();

    // get body as JSON array 
    JSONArray messages = resp.getBody().getArray();

    // print out each message
    messages.forEach(message -> System.out.println(message.toString()));
}

import UIKit
import PlaygroundSupport

var urlComponents = URLComponents(string: "https://beta.mrest.io/demo/messages")

// set the query parameters
var queryItems = [URLQueryItem]()
queryItems.append(URLQueryItem(name: "pagesize", value: "2"))
queryItems.append(URLQueryItem(name: "filter", value: "{\"from\":\"Bob\"}"))
urlComponents?.queryItems = queryItems

var urlRequest = URLRequest(url: (urlComponents?.url)!)

// set the key request header
urlRequest.setValue("demo", forHTTPHeaderField: "key")

// set request method
urlRequest.httpMethod = "GET"

URLSession.shared.dataTask(with: urlRequest) { (data, response, error) in
    guard let dataResponse = data, error == nil
    else {
        print(error?.localizedDescription ?? "Response Error")
        return
    }
    
    do {
        let jsonResponse = try JSONSerialization.jsonObject(with: dataResponse, options: [])
        print(jsonResponse)
    } catch let jsonError {
        print(jsonError)
    }
}.resume()

// only needed in playground
PlaygroundPage.current.needsIndefiniteExecution = true