Format of custom headers glob

Support
1

In netlify.toml, you can set custom headers like this:

[[headers]]
for = "/*.(jpg|jpeg|gif|png|ico|cur|gz|svg|svgz|mp4|ogg|ogv|webm|htc)"

What’s the format for this glob? Will /* match subdirectories? Is it equivalent to this regex ^/.*\.(jpg|jpeg|gif|png|ico|cur|gz|svg|svgz|mp4|ogg|ogv|webm|htc)$?

2

Sadly, the format does not support regexps, only the simple glob. You will need to create one rule per extension.

when you use “/*.jpg” as the target, it will cover every jpg file on your site.

3

I have a rule with (a|b) on my site. I think it’s working. Is that part of the glob rules?

4

I’m shocked to hear that and would recommend changing it ASAP for best behavior :slight_smile:

5

It’s definitely working? Here’s a rule in my netlify.toml:

[[headers]]
for = "/*.(css|ttf|ttc|otf|eot|woff|woff2)"
[headers.values]
Cache-Control = "public, max-age=31536000, immutable" # 1 year

And the output of curl -I for my CSS:

HTTP/2 200
accept-ranges: bytes
content-length: 66555
content-type: text/css; charset=UTF-8
date: Tue, 28 Apr 2020 14:24:32 GMT
etag: "3b33c3acedf8c2e98f4f5907cec086c6-ssl"
strict-transport-security: max-age=31536000
age: 0
server: Netlify
cache-control: public,max-age=31536000,immutable
x-nf-request-id: 8cd9eb23-8765-473d-b4eb-11f0a8bd611c-7325384

The Netlify CDN can’t have just coincidentally decided to add cache-control immutable, so the glob must be doing something…

6

Glad that format is working for you! It may stop working at any time, so if you want our advice, you’ve got it, and I think the peace of mind around changing one rule for 7 is totally worthwhile.

And you’re right - we would never ever add that particular header - our default caching is very carefully considered and your configuration (setting a long cache timeout) is a worst practice for most folks who do it without thinking it through. I guess you’ve probably seen this article, but in case you haven’t:

Not saying you need to change things - you seem pretty thoughtful and I guess you know you’ll not want to change a css file in the next year (though that seems quite suspect to me now that I say it out loud - for a font it makes sense, but really, for css?). I have just have spent so many hours troubleshooting for folks who set a timeout like that, and had to rename all their files to “dodge” their old, bad config - it’s super hard for us to debug since all we know is “that file is changed in our database” - we can’t see past caching headers settings easily.

But anyway, now you know the full story and can make the decisions that match your desired risk level and meet your goals best! :slight_smile:

7

My CSS file names are hashed, so there should never be a reason to use the same filename with old content.

Okay, good to know that my configuration working was only a coincidence and not by design. That was what I opened this issue to figure out: I’ve had this configuration for a while, but when I was reading the docs I couldn’t figure out why it actually worked. I guess the answer is that Netlify is using some globbing library internally today but might not tomorrow. I’ll change it when I get a chance.

1 Like
8

Why it is not working in my case. `[[headers]]
for = “/*.js”
[headers.values]
cache-control = “max-age=31536000”

for = "/*.css"
[headers.values]
    cache-control = "max-age=31536000"

for = "/*.woff"
[headers.values]
    cache-control = "max-age=31536000"

for = "/*.png"
[headers.values]
    cache-control = "max-age=31536000"
`

Here only the .js file gets bundled but in the network tab, I see for: “/*.png” on bundle.js header. That means bundle.js is getting the header for “/*png”. Why? And why other are not working?

9

Edited:

You’re indenting it as though that affects the value. It does not. It’s just there for human readability. The computer ignores it.

You need to add more [[headers]] to separate the entries. Like this:

[[headers]]
for = "/*.css"
[headers.values]
Cache-Control = "public, max-age=31536000, immutable" # 1 year

[[headers]]
for = "/*.gif"
[headers.values]
Cache-Control = "public, max-age=1209600" # 2 weeks
2 Likes
10

Thanks,` @carlana Now it works for all files except .html files.

[[headers]]
for = "/*.html"
[headers.values]
    Cache-Control = '''
    public,
    max-age=36000,
    must-revalidate'''

Don’t know why this happens. It happens for all.HTML files including index.html

11

Thanks so much for jumping in @carlana :trophy:

@Nakib, we’ve responded to you over here → Setting response headers only on documents - #25 by Nakib