Fix #11

cmd/conf/configuration.go

@@ -63,6 +63,8 @@ type Conf struct {
 
 	WaitForEOF bool
 
+	AllowBots bool
+
 	cmdFlagSet *pflag.FlagSet
 
 	sstlsLoc    string

cmd/conf/download.go

@@ -76,7 +76,7 @@ func (c *Conf) setupDownloadRoute(args []string, srvr *server.Server) (*server.R
 		header.Set(k, v)
 	}
 
-	route.HandlerFunc = handlers.HandleDownload(file, !c.NoDownload, header, srvr.InfoLog)
+	route.HandlerFunc = handlers.HandleDownload(file, !c.NoDownload, !c.AllowBots, header, srvr.InfoLog)
 
 	return route, nil
 }

cmd/conf/flags.go

@@ -187,6 +187,12 @@ See also: --upload-file; -u, --upload; -L, --no-unix-eol-norm`,
 
 	flags.BoolVarP(&c.WaitForEOF, "wait-for-eof", "J", false, `Wait for EOF before starting HTTP(S) server if serving from stdin.
 This flag does noting if not serving from stdin.
+`,
+	)
+
+	flags.BoolVarP(&c.AllowBots, "allow-bots", "B", false, `Allow bots to attempt download.
+By default, bots are prevented from attempting the download; this is required to allow links to be sent over services that provide previews such as Apple iMessage.
+A client is considered to be a bot if the 'User-Agent' header contains either 'bot', 'Bot' or 'facebookexternalhit'.
 `,
 	)
 }

internal/handlers/download.go

@@ -12,7 +12,7 @@ import (
 	"github.com/raphaelreyna/oneshot/internal/server"
 )
 
-func HandleDownload(file *file.FileReader, download bool, header http.Header,
+func HandleDownload(file *file.FileReader, download, noBots bool, header http.Header,
 	infoLog *log.Logger) func(w http.ResponseWriter, r *http.Request) error {
 	msg := "transfer complete:\n"
 	msg += "\tname: %s\n"
@@ -88,7 +88,7 @@ func HandleDownload(file *file.FileReader, download bool, header http.Header,
 
 	return func(w http.ResponseWriter, r *http.Request) error {
 		// Filter out requests from bots, iMessage, etc.
-		if headers, exists := r.Header["User-Agent"]; exists {
+		if headers, exists := r.Header["User-Agent"]; exists && noBots {
 			for _, header := range headers {
 				isBot := strings.Contains(header, "bot")
 				if !isBot {