feat: act as HTTP PROXY for http://<cidv1b32>.ipfs.localhost

[alanshaw]

PoC right now, but you get the idea.

⨎ curl -v --proxy 'http://127.0.0.1:8180' 'http://bafybeih4mncb4apdnrvbnqkicldf74sfstykoryzi7noaf4njxkiuflnay.ipfs.localhost/658.png' > 658.png
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to 127.0.0.1 (127.0.0.1) port 8180 (#0)
> GET http://bafybeih4mncb4apdnrvbnqkicldf74sfstykoryzi7noaf4njxkiuflnay.ipfs.localhost/658.png HTTP/1.1
> Host: bafybeih4mncb4apdnrvbnqkicldf74sfstykoryzi7noaf4njxkiuflnay.ipfs.localhost
> User-Agent: curl/7.54.0
> Accept: */*
> Proxy-Connection: Keep-Alive
>
< HTTP/1.1 200 OK
< content-type: application/octet-stream
< cache-control: no-cache
< Date: Fri, 12 Jul 2019 14:20:44 GMT
< Connection: keep-alive
< Transfer-Encoding: chunked
<
{ [16211 bytes data]
100  853k    0  853k    0     0  30.0M      0 --:--:-- --:--:-- --:--:-- 30.8M
* Connection #0 to host 127.0.0.1 left intact

refs ipfs/kubo#5982

License: MIT
Signed-off-by: Alan Shaw alan.shaw@protocol.ai

[lidel]

Really cool! While we are at it, would be cool to implement DNSLink and Subdomain gateway too (#2248).
HTTP proxy mode (#1877) is a cherry on top 🍒

[achingbrain]

Thank you so much for opening this PR and for your patience in getting it merged. js-ipfs is being deprecated in favor of Helia. You can #4336 and read the migration guide.

This has largely been superseded by https://specs.ipfs.tech/http-gateways/path-gateway/ - any changes should be suggested as IPIPs to the spec.