b2: Fix link sharing #3314

backend/b2/b2.go

@@ -629,6 +629,10 @@ func (f *Fs) list(ctx context.Context, dir string, recurse bool, prefix string,
 		if err != nil {
 			return err
 		}
+		// Check that there are matching files
+		if len(response.Files) == 0 {
+			return fs.ErrorDirNotFound
+		}
 		for i := range response.Files {
 			file := &response.Files[i]
 			// Finish if file name no longer has prefix
@@ -1227,6 +1231,15 @@ func (f *Fs) PublicLink(ctx context.Context, remote string) (link string, err er
 	} else {
 		RootURL = f.opt.DownloadURL
 	}
+	_, err = f.NewObject(ctx, remote)
+	if err == fs.ErrorObjectNotFound || err == fs.ErrorNotAFile {
+		err = f.list(ctx, remote, false, "", 1, f.opt.Versions, func(remote string, object *api.File, isDirectory bool) error {
+			return errEndList
+		})
+	}
+	if err != nil {
+		return "", err
+	}
 	absPath := "/" + path.Join(f.root, remote)
 	link = RootURL + "/file/" + urlEncode(f.bucket) + absPath
 	bucketType, err := f.getbucketType()

docs/content/b2.md

@@ -301,6 +301,34 @@ server to the nearest millisecond appended to them.
 Note that when using `--b2-versions` no file write operations are
 permitted, so you can't upload files or delete them.
 
+### B2 and rclone link ###
+
+Rclone supports generating file share links for private B2 buckets.
+They can either be for a file for example:
+
+```
+./rclone link B2:bucket/path/to/file.txt
+https://f002.backblazeb2.com/file/bucket/path/to/file.txt?Authorization=xxxxxxxx
+
+```
+
+or if run on a directory you will get:
+
+```
+./rclone link B2:bucket/path
+https://f002.backblazeb2.com/file/bucket/path?Authorization=xxxxxxxx
+```
+
+you can then use the authorization token (the part of the url from the
+ `?Authorization=` on) on any file path under that directory. For example:
+
+```
+https://f002.backblazeb2.com/file/bucket/path/to/file1?Authorization=xxxxxxxx
+https://f002.backblazeb2.com/file/bucket/path/file2?Authorization=xxxxxxxx
+https://f002.backblazeb2.com/file/bucket/path/folder/file3?Authorization=xxxxxxxx
+
+```
+
 <!--- autogenerated options start - DO NOT EDIT, instead edit fs.RegInfo in backend/b2/b2.go then run make backenddocs -->
 ### Standard Options