Open Bug 973580 Opened 6 years ago Updated Last year

Indicate why Font fails to load from local filesystem (Downloadable font: download failed)


(DevTools :: Console, defect, P3)

28 Branch


(Not tracked)


(Reporter: fb+mozdev, Unassigned)



+++ This bug was initially created as a clone of Bug #760436 +++

Steps to reproduce:

- Use sth like `<link rel="stylesheet" href="../Assets/Fonts/Proxima Nova/proxima-nova.css"/>` in your HTML file.
- The `proxima-nova.css` defines an @font-face with a src in the same directory.
- Load the HTML from the local file system (file: protocol).

Actual results:

Console (where "CSS" needs to be enabled first): 
downloadable font: download failed (font-family: "Proxima Nova" style:normal weight:normal stretch:normal src index:1): status=2147500037
source: file:///[…]/Assets/Fonts/Proxima%20Nova/ProximaNova-Regular.otf

Expected results:

Log this as a *security error* with a message like: 
`downloadable font: download not allowed due to same origin restriction (see KBxxxxx)`

(This may also apply for same-origin violations with the http: or https: scheme.)
http font loads that are blocked by same-origin restriction get logged in the developer console, e.g. when visiting, I see:

- - - - -
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at This can be fixed by moving the resource to the same domain or enabling CORS.
downloadable font: download failed (font-family: "EmojiSymbols" style:normal weight:normal stretch:normal src index:0): bad URI or cross-site access not allowed
- - - - -

This was a fairly recent enhancement (bug 713980). Maybe what was done there should be made to apply to file: URLs as well?
I think your test case needs amending. When the WOFF file is in the same directory as the CSS file I would expect the font to be rendered, not blocked. This is a legitimate use case where people wish to download or develop a website offline and find that any pages in sub-directories are not rendering the font due to Bug 760436 - Font fails to load from local filesystem Downloadable font: download failed
"or enabling CORS" should probably be "or enabling CORS for that resource". Or something that gives a little more detail about what "enabling CORS" is exactly.
Without the qualifier it sounds like CORS is a user-level pref that can be enabled.
Is this a webconsole bug? Can we move it to Core:Layout Text?
Product: Firefox → DevTools
Priority: -- → P3
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