feat: Support alternative transfer.sh instances

cmd/sshare/sshare.go

@@ -12,6 +12,7 @@ import (
 )
 
 var (
+	tshInstanceURL    string   = transfer.DefaultTransferBaseURL
 	transferDownloads int      = 0
 	transferDays      int      = 0
 	sshAgentPath      string   = os.Getenv("SSH_AUTH_SOCK")
@@ -33,6 +34,9 @@ var (
 			if transferDownloads <= 0 {
 				ui.Errorln("Uploaded content must be downloadable via transfer.sh for at least 1 time", true)
 			}
+			if err := transfer.SetTransferShURL(tshInstanceURL); err != nil {
+				ui.Errorln("Transfer.sh URL is not valid: "+err.Error(), true)
+			}
 			return nil
 		},
 		Run: func(cmd *cobra.Command, args []string) {
@@ -139,6 +143,7 @@ func init() {
 	rootCmd.Flags().StringVarP(&githubToken, "github-token", "g", githubToken, "github token with permission to read ssh keys")
 	rootCmd.Flags().StringSliceVarP(&keyFilepaths, "key-file", "f", keyFilepaths, "additional key file(s) to include in the generated authorized_keys")
 	rootCmd.Flags().StringSliceVarP(&rawKeys, "key", "k", rawKeys, "additional keys to include in the generated authorized_keys")
+	rootCmd.PersistentFlags().StringVar(&tshInstanceURL, "url", transfer.DefaultTransferBaseURL, "url of the target transfer.sh instance")
 	rootCmd.Flags().IntVarP(&transferDownloads, "max-downloads", "m", 10, "maximum number of times any content shared can be downloaded")
 	rootCmd.Flags().IntVarP(&transferDays, "max-days", "d", 2, "number of days that the content will remain available via transfer.sh")
 	rootCmd.AddCommand(deleteCmd)

internal/transfer/upload.go

@@ -19,9 +19,24 @@ type TransferSh struct {
 
 const (
 	// TransferBaseURL is the base URL of transfer.sh using https.
-	TransferBaseURL string = "https://transfer.sh"
+	DefaultTransferBaseURL string = "https://transfer.sh"
 )
 
+var (
+	transferBaseURL string = DefaultTransferBaseURL
+)
+
+func SetTransferShURL(tshURL string) error {
+	if u, err := url.Parse(tshURL); err != nil {
+		return fmt.Errorf("invalid transfer.sh url: %w", err)
+	} else if u.Scheme != "http" && u.Scheme != "https" {
+		return fmt.Errorf("transfer.sh url not http or https scheme")
+	} else {
+		transferBaseURL = u.String()
+	}
+	return nil
+}
+
 // NewTransferSh returns an instance of a TransferSh config with appropriate
 // default value for the context. Specifically, the file name is set to
 // authorized_keys with a max of 10 downloads and a life of 2 days.
@@ -57,7 +72,7 @@ func (tsh TransferSh) WithMaxDays(maxDays int) TransferSh {
 // transfer.sh. Returned are the URLs to both download/curl the file and to
 // delete the file form transfer.sh. If the upload fails, an error is returned.
 func (tsh TransferSh) Upload(data string) (*TransferShFile, error) {
-	uploadURL, err := url.JoinPath(TransferBaseURL, tsh.fileName)
+	uploadURL, err := url.JoinPath(transferBaseURL, tsh.fileName)
 	if err != nil {
 		return nil, fmt.Errorf("failed to build upload url for transfer.sh: %w", err)
 	}
@@ -86,5 +101,5 @@ func (tsh TransferSh) Upload(data string) (*TransferShFile, error) {
 	if deleteURL == "" || downloadURL == "" {
 		return nil, fmt.Errorf("failed to obtain all urls for the transfer.sh upload")
 	}
-    return NewFile(downloadURL, path.Base(deleteURL)), nil
+	return NewFile(downloadURL, path.Base(deleteURL)), nil
 }