Gateway content-type response header

[uptownhr]

Is there a way to set the header of what the gateway will return as content-type. I have an issue right now when serving svg files. Since the content-type is text, browsers do not recognize it properly and will not display the image.

[lidel]

I feel this requires clarification, as it may not be clear what is wrong on the first sight.

Sample SVG image at /ipfs/QmWBNMp6JxXj5aYrpef8z2xaPC7DeGftG4jTy6EyF958o4
is returned with Content-Type: text/xml and when opened directly it renders just fine under both Firefox 51 and Chromium 56. 👌

The problem is that resource returned as text/xml can't be rendered as <img src=" or CSS background. If you open svg-mimetype-example.html you will see <img> is not rendered and alt text is displayed instead. 👎

My guess is that go-ipfs probably uses standard mime-type sniffer from golang [1] which defaults to text/xml
Correct mime-type for image contexts in browser is image/svg+xml [2,3]

It does not seem to work correctly now, but you may want to subscribe to related issues about mime-type in go-ipfs:

• indicate filename/mime-type to ipfs add -w  ipfs/kubo#1055
• Need more support mime-types. ipfs/kubo#2164

---

1: https://golang.org/src/net/http/sniff.go
2: https://www.w3.org/TR/SVGTiny12/mimereg.html
3: https://developer.mozilla.org/en-US/docs/Web/SVG/Tutorial/Getting_Started#SVG_File_Types

[uptownhr]

awesome, thank you

Maybe it helps to wrap the svg in a directory, in order to have it addressed with a .svg filename:

> ipfs add -w file.svg
added Qmsvg file.svg
added Qmfoo
# => /ipfs/Qmfoo/file.svg

[lidel]

Indeed! If extension is .svg:

<img src="https://ipfs.io/ipfs/QmQ48wa7jc9JZJ9Lc1XCkuwa3FUYeXcMPJi3vAD78VbBM1/sample.svg" alt="if you see this text it means SVG image failed to load"/>

it IS returned as Content-Type:"image/svg+xml" and renders correctly:
/ipfs/QmRYdrzpspUpeDgn1au2L6jNYuo9SZN2TD4FABn9dY9jra/svg-mimetype-example2.html ✨

[Kubuxu]

The content type detection from the content is only heuristic, so it is better to use file extension for deterministic content type.

[madavieb]

This issue has been moved to https://discuss.ipfs.io/t/gateway-content-type-response-header/357.