s3signer

s3signer.go

package main

import (
	"flag"
	"fmt"
	"log"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/aws/external"
	"github.com/aws/aws-sdk-go-v2/service/s3"
)

var (
	bucket = flag.String("b", "", "the name of the bucket where the object lives")
	key    = flag.String("k", "", "the key for the object that you want to share")
	region = flag.String("r", "eu-west-1", "the region you want to use, the default is eu-west-1")
)

func main() {
	flag.Parse()
	if len(*bucket) == 0 {
		log.Fatal("no bucketname provided")
	}
	if len(*key) == 0 {
		log.Fatal("no key name provided")
	}
	cfg, err := external.LoadDefaultAWSConfig()
	if err != nil {
		log.Fatalf("unable to load default AWS config %v", err)
	}
	cfg.Region = *region
	url, err := s3signer(cfg, bucket, key)
	if err != nil {
		log.Fatalf("unable to generate signed URL %v", err)
	}
	fmt.Printf("\nShare this: %v\n", url)
}

func s3signer(cfg aws.Config, bucket *string, key *string) (string, error) {
	svc := s3.New(cfg)
	obj := svc.GetObjectRequest(&s3.GetObjectInput{
		Bucket: aws.String(*bucket),
		Key:    aws.String(*key)})

	//valid for an hour
	urlstr, err := obj.Presign(1 * 60 * time.Minute)
	if err != nil {
		log.Println("failed to sign request", err)
		return "", err
	}
	return urlstr, nil
}