Serve a sample JSON payload in Crystal

server.cr

require "http"
require "uuid"
require "uuid/json"

class App
  include HTTP::Handler

  def call(context)
    Fiber.yield # Simulate getting data from the DB
    response_payload.to_json context.response
  end

  def response_payload
    products = [
      {
        id: UUID.random,
        name: "The First Product",
        description: "This is the first product in the collection",
        price_cents: 1000_00,
      },
      {
        id: UUID.random,
        name: "The Second Product",
        description: "This is the second product in the collection",
        price_cents: 1000_00,
      },
      {
        id: UUID.random,
        name: "The Third Product",
        description: "This is the third product in the collection",
        price_cents: 1000_00,
      },
    ]

    {
      customer: {
        id: UUID.random,
        name: "Jamie Gaskins",
        email: "[email protected]",
        created_at: Time.now,
        updated_at: Time.now,
      },
      order: {
        id: UUID.random,
        product_ids: products.map{ |p| p[:id] },
      },
      products: products,
    }
  end
end

port = ARGV.first.to_i
puts "Listening on #{port}"
HTTP::Server.new([App.new]).listen port

server.go

// Golang server for comparison to the Crystal version

package main

import (
  "log"
  "net/http"
  "time"
  "encoding/json"
  "github.com/satori/go.uuid"
)

type Product struct {
  Id string `json:"id"`
  Name string `json:"name"`
  Description string `json:"description"`
  PriceCents int32 `json:"price_cents"`
}
type Products []Product

type Customer struct {
  Id string `json:"id"`
  Name string `json:"name"`
  Email string `json:"email"`
  CreatedAt time.Time `json:"created_at"`
  UpdatedAt time.Time `json:"updated_at"`
}

type Order struct {
  Id string `json:"id"`
  ProductIds []string `json:"product_ids"`
}

type Payload struct {
  Customer Customer `json:"customer"`
  Order Order `json:"order"`
  Products Products `json:"products"`
}

func main() {
  http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
    guid, _ := uuid.NewV4()
    id := guid.String()

    products := Products{
      Product{
        Id: id,
        Name: "The First Product",
        Description: "This is the first product in the collection",
        PriceCents: 100000,
      },
      Product{
        Id: id,
        Name: "The Second Product",
        Description: "This is the second product in the collection",
        PriceCents: 100000,
      },
      Product{
        Id: id,
        Name: "The Third Product",
        Description: "This is the third product in the collection",
        PriceCents: 100000,
      },
    }
    product_ids := []string {
      id,
      id,
      id,
    }

    payload := Payload{
      Customer: Customer{
        Id: id,
        Name: "Jamie Gaskins",
        Email: "[email protected]",
        CreatedAt: time.Now(),
        UpdatedAt: time.Now(),
      },
      Order: Order{
        Id: id,
        ProductIds: product_ids,
      },
      Products: products,
    }

    json.NewEncoder(w).Encode(payload)
  })

  log.Fatal(http.ListenAndServe(":54321", nil))
}