Escape message IDs when constructing URLs

Message IDs can include characters that must escaped before being
included in the path part of public-inbox URLs.  Add a variant of
url-hexify-string that uses the same set of characters as
public-inbox's mid_escape().

Message-Id: <20200919044639.26871-2-kyle@kyleam.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/piem-b4.el b/piem-b4.el
index b77d111..596e563 100644
--- a/piem-b4.el
+++ b/piem-b4.el
@@ -66,7 +66,7 @@
                  (mid (piem-mid))
                  (buffer (condition-case nil
                              (piem-download-and-decompress
-                              (concat url mid "/t.mbox.gz"))
+                              (concat url (piem-escape-mid mid) "/t.mbox.gz"))
                            (error nil))))
         (with-current-buffer buffer
           (write-region nil nil mbox-thread))