Function SignV2

pkg/signer/request-signature-v2.go:130–160

Authorization = "AWS" + " " + AWSAccessKeyId + ":" + Signature; Signature = Base64( HMAC-SHA1( YourSecretAccessKeyID, UTF-8-Encoding-Of( StringToSign ) ) ); StringToSign = HTTP-Verb + "\n" + Content-Md5 + "\n" + Content-Type + "\n" + Date + "\n" + CanonicalizedProtocolHeaders + CanonicalizedRe

(req http.Request, accessKeyID, secretAccessKey string, virtualHost bool)

// SignV2 sign the request before Do() (AWS Signature Version 2).
func SignV2(req http.Request, accessKeyID, secretAccessKey string, virtualHost bool) *http.Request {
	// Signature calculation is not needed for anonymous credentials.
	if accessKeyID == "" || secretAccessKey == "" {
		return &req
	}

	// Initial time.
	d := time.Now().UTC()

	// Add date if not present.
	if date := req.Header.Get("Date"); date == "" {
		req.Header.Set("Date", d.Format(http.TimeFormat))
	}

	// Calculate HMAC for secretAccessKey.
	stringToSign := stringToSignV2(req, virtualHost)
	hm := hmac.New(sha1.New, []byte(secretAccessKey))
	hm.Write([]byte(stringToSign))

	// Prepare auth header.
	authHeader := new(bytes.Buffer)
	fmt.Fprintf(authHeader, "%s %s:", signV2Algorithm, accessKeyID)
	encoder := base64.NewEncoder(base64.StdEncoding, authHeader)
	encoder.Write(hm.Sum(nil))
	encoder.Close()

	// Set Authorization header.
	req.Header.Set("Authorization", authHeader.String())

	return &req
}

// From the Amazon docs:
//