detect_s3.go

package getter

import (
	"fmt"
	"net/url"
	"strings"
)

const (
	vhostFormat = ""
)

// S3Detector implements Detector to detect S3 URLs and turn
// them into URLs that the S3 getter can understand.
type S3Detector struct{}

func (d *S3Detector) Detect(src, _ string) (string, bool, error) {
	if len(src) == 0 {
		return "", false, nil
	}

	if strings.Contains(src, ".amazonaws.com/") {
		return d.detectHTTP(src)
	}

	return "", false, nil
}

func (d *S3Detector) detectHTTP(src string) (string, bool, error) {
	parts := strings.Split(src, "/")
	if len(parts) < 0 {
		return "", false, fmt.Errorf(
			"URL is not a valid S3 URL")
	}

	hostParts := strings.Split(parts[0], ".")
	if len(hostParts) == 3 {
		return d.detectPathStyle(hostParts[0], parts[1:])
	} else if len(hostParts) == 4 {
		return d.detectVhostStyle(hostParts[1], hostParts[0], parts[1:])
	} else {
		return "", false, fmt.Errorf(
			"URL is not a valid S3 URL")
	}
}

func (d *S3Detector) detectPathStyle(region string, parts []string) (string, bool, error) {
	urlStr := fmt.Sprintf("https://%s.amazonaws.com/%s", region, strings.Join(parts, "/"))
	url, err := url.Parse(urlStr)
	if err != nil {
		return "", true, fmt.Errorf("error parsing GitHub URL: %s", err)
	}

	return "s3::" + url.String(), true, nil
}

func (d *S3Detector) detectVhostStyle(region, bucket string, parts []string) (string, bool, error) {
	urlStr := fmt.Sprintf("https://%s.amazonaws.com/%s/%s", region, bucket, strings.Join(parts, "/"))
	url, err := url.Parse(urlStr)
	if err != nil {
		return "", true, fmt.Errorf("error parsing S3 URL: %s", err)
	}

	return "s3::" + url.String(), true, nil
}

// func (d *S3Detector) detectSSH(src string) (string, bool, error) {
// 	idx := strings.Index(src, ":")
// 	qidx := strings.Index(src, "?")
// 	if qidx == -1 {
// 		qidx = len(src)
// 	}

// 	var u url.URL
// 	u.Scheme = "ssh"
// 	u.User = url.User("git")
// 	u.Host = "github.com"
// 	u.Path = src[idx+1 : qidx]
// 	if qidx < len(src) {
// 		q, err := url.ParseQuery(src[qidx+1:])
// 		if err != nil {
// 			return "", true, fmt.Errorf("error parsing GitHub SSH URL: %s", err)
// 		}

// 		u.RawQuery = q.Encode()
// 	}

// 	return "git::" + u.String(), true, nil
// }