Web Server Example

A complete Go web server that serves today’s APOD as HTML and provides a JSON API for near-Earth objects.

package main

import (
  "context"
  "encoding/json"
  "html/template"
  "log"
  "net/http"
  "os"
  "time"

  "github.com/peteretelej/nasa"
)

var apodTmpl = template.Must(template.New("apod").Parse(`<!DOCTYPE html>
<html><head><title>{{.Title}}</title></head><body>
<h1>{{.Title}}</h1>
<p>{{.Explanation}}</p>
{{if eq .MediaType "video"}}
<iframe src="{{.URL}}" width="800" height="450" frameborder="0" allowfullscreen></iframe>
{{else}}
<img src="{{.URL}}" style="max-width:800px">
{{end}}
</body></html>`))

func main() {
  client := nasa.NewClient(
    nasa.WithAPIKey(os.Getenv("NASA_API_KEY")),
  )

  http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
    ctx, cancel := context.WithTimeout(r.Context(), 10*time.Second)
    defer cancel()

    apod, err := client.APOD.Today(ctx)
    if err != nil {
      http.Error(w, err.Error(), http.StatusBadGateway)
      return
    }

    w.Header().Set("Content-Type", "text/html; charset=utf-8")
    if err := apodTmpl.Execute(w, apod); err != nil {
      log.Printf("template error: %v", err)
    }
  })

  http.HandleFunc("/api/neo", func(w http.ResponseWriter, r *http.Request) {
    ctx, cancel := context.WithTimeout(r.Context(), 10*time.Second)
    defer cancel()

    now := time.Now()
    feed, err := client.NEO.Feed(ctx, now, now.AddDate(0, 0, 6))
    if err != nil {
      http.Error(w, err.Error(), http.StatusBadGateway)
      return
    }

    w.Header().Set("Content-Type", "application/json")
    if err := json.NewEncoder(w).Encode(feed); err != nil {
      log.Printf("encode error: %v", err)
    }
  })

  log.Println("Listening on :8080")
  log.Fatal(http.ListenAndServe(":8080", nil))
}

Endpoints

Path	Method	Description
`/`	GET	Today’s APOD rendered as HTML
`/api/neo`	GET	Near-Earth objects for the next 7 days (JSON)

Running

export NASA_API_KEY="your-key"
go run main.go

Open http://localhost:8080 for the APOD page, or http://localhost:8080/api/neo for NEO JSON data.