Basic Usage Examples

Basic Usage Examples

Common patterns for working with the NASA Go SDK.

Error Handling with Type Switches

package main

import (
  "context"
  "errors"
  "fmt"
  "log"
  "os"

  "github.com/peteretelej/nasa"
)

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

  apod, err := client.APOD.Today(context.Background())
  if err != nil {
    var rateLimitErr *nasa.RateLimitError
    var authErr *nasa.AuthError
    var notFoundErr *nasa.NotFoundError
    var apiErr *nasa.APIError

    switch {
    case errors.As(err, &rateLimitErr):
      fmt.Printf("Rate limited: %s\n", rateLimitErr)
    case errors.As(err, &authErr):
      fmt.Printf("Auth error: %s\n", authErr)
    case errors.As(err, &notFoundErr):
      fmt.Printf("Not found: %s\n", notFoundErr)
    case errors.As(err, &apiErr):
      fmt.Printf("API error: %s\n", apiErr)
    default:
      log.Fatal(err)
    }
    return
  }

  fmt.Println(apod.Title)
}

Context with Timeout

package main

import (
  "context"
  "fmt"
  "log"
  "os"
  "time"

  "github.com/peteretelej/nasa"
)

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

  ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
  defer cancel()

  apod, err := client.APOD.Today(ctx)
  if err != nil {
    log.Fatal(err)
  }

  fmt.Println(apod.Title)
}

Concurrent API Calls

Use goroutines to call multiple APIs in parallel:

package main

import (
  "context"
  "fmt"
  "log"
  "os"
  "sync"
  "time"

  "github.com/peteretelej/nasa"
)

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

  ctx := context.Background()
  var wg sync.WaitGroup
  wg.Add(2)

  var apod *nasa.APODImage
  var feed *nasa.NEOFeed
  var apodErr, neoErr error

  go func() {
    defer wg.Done()
    apod, apodErr = client.APOD.Today(ctx)
  }()

  go func() {
    defer wg.Done()
    now := time.Now()
    feed, neoErr = client.NEO.Feed(ctx, now, now.AddDate(0, 0, 6))
  }()

  wg.Wait()

  if apodErr != nil {
    log.Printf("APOD error: %v", apodErr)
  } else {
    fmt.Printf("APOD: %s\n", apod.Title)
  }

  if neoErr != nil {
    log.Printf("NEO error: %v", neoErr)
  } else {
    fmt.Printf("NEOs this week: %d\n", feed.ElementCount)
  }
}

Legacy Convenience Functions

The package provides backward-compatible convenience functions that use a default client:

package main

import (
  "fmt"
  "log"

  "github.com/peteretelej/nasa"
)

func main() {
  // Get today's APOD (uses DEMO_KEY)
  img, err := nasa.APODToday()
  if err != nil {
    log.Fatal(err)
  }
  fmt.Printf("%s: %s\n", img.Title, img.URL)

  // Get a random APOD
  random, err := nasa.RandomAPOD()
  if err != nil {
    log.Fatal(err)
  }
  fmt.Printf("Random: %s\n", random.Title)
}

These return the legacy *Image type. For full features, use NewClient with service methods that return *APODImage.

Using a Registered API Key

package main

import (
  "fmt"
  "log"
  "os"
  "time"

  "github.com/peteretelej/nasa"
)

func main() {
  // Convenience functions with an API key
  apod, err := nasa.APODTodayWithKey(os.Getenv("NASA_API_KEY"))
  if err != nil {
    log.Fatal(err)
  }
  fmt.Println(apod.Title)

  // NEO feed with an API key
  now := time.Now()
  feed, err := nasa.NEOFeedWithKey(
    os.Getenv("NASA_API_KEY"),
    now.Format("2006-01-02"),
    now.AddDate(0, 0, 6).Format("2006-01-02"),
  )
  if err != nil {
    log.Fatal(err)
  }
  fmt.Printf("NEOs: %d\n", feed.ElementCount)
}