EpubCCEPUBCheck RSC-031: remote resource over HTTP
Updated:
EPUBCheck RSC-031 is a warning message: “Remote resource references should use HTTPS, but found "…".” A remote resource is referenced with http instead of https. It is a warning: some reading apps block insecure connections, so the resource may not load.
The official message
Remote resource references should use HTTPS, but found "%1$s".
- Default severity
- Warning. The EPUB is still valid, but something is likely to cause problems in some reading apps. EPUBCheck exits with 0 unless you pass --failonwarnings.
- EPUBCheck version
- 5.4.0
%1$s, %2$s… are filled in with the file, value or element EPUBCheck found.
Typical causes
- Old links or remote media that were never updated to https.
- Remote audio, video or fonts copied from an old project or from a server that has since moved to https.
How to fix it
- Find the URL named in the message.
- Change it to https if the server supports it.
- If the resource is essential, consider storing it inside the EPUB instead, so the book does not depend on a server or a network connection, then validate again.
When it's not this
If the remote resource is not allowed to be remote at all, the error is RSC-006.
Terms used here
Other RSC messages
RSC-030File URLs are not allowed in EPUB, but found "…".RSC-032Fallback must be provided for foreign resources, but found none for resource "…" of type "…".RSC-029Data URL is not allowed in this context.RSC-033Relative URL strings must not have a query component, but found one in "…".RSC-028XML documents must be encoded in UTF-8, but … was detected.RSC-034Scripts must have a JavaScript media type.
Sources
Message text and severity from EPUBCheck 5.4.0 (W3C, BSD-3-Clause). Explanation by EpubCC.