Go

Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.

Cosmic makes a great Go CMS for your websites and apps.

Before adding any code, make sure to follow the Initial Setup at the start of this section to set up your content in Cosmic. Then take the following steps to add Cosmic-powered content to your Go apps:

1. Go app setup

If you don't have Go installed on your machine, you may need to start by installing Go by following the documentation.

After everything is ready, create a folder which will contain all of our code:


mkdir go-cosmic-app
cd go-cosmic-app

2. Install `godotenv` package


go mod init go-cosmic-app
go get github.com/joho/godotenv

3. Create `.env`

Create a .env file and add cosmic bucket configuration. You can find your Bucket slug and API read key in Bucket Settings > API Access after logging in.


# Set these values, found in Bucket > Settings after logging in at https://app.cosmicjs.com/
BUCKET_SLUG= # Required
READ_KEY= # Required if activated in the bucket

4. Create HTTP Server and Route

Create a app.go file and paste the following code:


// app.go
package main
import (
    "encoding/json"
    "fmt"
    "html/template"
    "io/ioutil"
    "log"
    "net/http"
    "github.com/joho/godotenv"
    "os"
)
// Data is a array of objects from Cosmic API
type Data struct {
    Objects []Post
}
// Post is a representation of post object
type Post struct {
    Title    string
    Slug     string
    Content  template.HTML
    Metadata Metadata
}
// Metadata is a representation of metadata object
type Metadata struct {
    Hero Image
}
// Image is a object of URL & ImgixURL
type Image struct {
    URL      string
    ImgixURL string `json:"imgix_url"`
}
func indexHandler(w http.ResponseWriter, r *http.Request) {
  if r.URL.Path != "/" {
    http.Error(w, "404 not found.", http.StatusNotFound)
    return
  }
  if r.Method != "GET" {
    http.Error(w, "Method is not supported.", http.StatusNotFound)
    return
  }
  if ok := checkIfEnvExists("BUCKET_SLUG"); !ok {
    http.Error(w, "BUCKET_SLUG is not present in the .env", http.StatusInternalServerError)
    return
  }
  var readKey string
  if ok := checkIfEnvExists("READ_KEY"); ok {
    readKey = "&read_key=" + os.Getenv("READ_KEY")
  }
  bucketSlug := os.Getenv("BUCKET_SLUG")
  apiURL := "https://api.cosmicjs.com/v2/"
  url := apiURL + bucketSlug + '/objects?query=%7B"type":"posts"%7D&props=slug,title,content,metadata' + readKey
  res, err := http.Get(url)
  var data Data
  if err != nil {
    log.Println(err)
  } else {
    body, err := ioutil.ReadAll(res.Body)
    if err != nil {
      log.Println(err)
    } else {
      json.Unmarshal(body, &data)
    }
  }
  t, _ := template.ParseFiles("index.html")
  t.Execute(w, data)
}
func getPortEnv() string {
  var port string
  var ok bool
  if port, ok = os.LookupEnv("PORT"); !ok {
    port = "8080"
  }
  return ":" + port
}
func checkIfEnvExists(key string) bool {
  var ok bool
  if _, ok = os.LookupEnv(key); !ok {
    return false
  }
  return true
}
func main() {
  http.HandleFunc("/", indexHandler)
  if err := godotenv.Load(); err != nil {
    log.Fatal("Error loading .env file")
  }
  port := getPortEnv()
  fmt.Println("Starting server at port", port)
  if err := http.ListenAndServe(port, nil); err != nil {
    log.Fatal(err)
  }
}

5. Add template

Create index.html file and paste the following code:


<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <title>Go Cosmic Blog</title>
    <meta name="description" content="Go Cosmic Blog" />
    <meta name="author" content="Cosmic" />
    <style>
      body {
        font-family: Avenir, Helvetica, Arial, sans-serif;
        -webkit-font-smoothing: antialiased;
        -moz-osx-font-smoothing: grayscale;
        text-align: left;
        color: #2c3e50;
      }
    </style>
  </head>
  <body>
    <div>
      <h1>Go Cosmic Blog</h1>
      {{if not .Objects}}
      <h2>No post found</h2>
      {{end}} {{range .Objects}}
      <article>
        <h3>{{ .Title }}</h3>
        <img alt="{{.Title}}" src="{{.Metadata.Hero.ImgixURL}}?w=400" />
        {{.Content}}
      </article>
      {{end}}
    </div>
  </body>
</html>

6. Start your app

Start your app, and go to http://localhost:8080. Dance 🎉


go run app.go

Go