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Ilia Denisov 1855e43699
Tests · Go / test (push) Successful in 1m42s
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Tests · Integration / integration (pull_request) Successful in 1m36s
gateway: add CORS allow-list for the public REST surface
Adds a `GATEWAY_PUBLIC_HTTP_CORS_ALLOWED_ORIGINS` env-driven allow-list
on the public REST server so the dev UI on https://www.galaxy.lan can
call https://api.galaxy.lan without the browser blocking the
cross-origin response. Defaults to empty (no CORS) so the production
posture stays closed.

The middleware mounts before route classification and anti-abuse, so
OPTIONS preflights never charge against per-class rate-limit buckets.

`tools/dev-deploy/docker-compose.yml` opts the dev gateway into a
single allowed origin (`https://www.galaxy.lan`); local-dev keeps the
defaults because Vite proxies through the same origin.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-15 07:58:14 +02:00

53 lines
1.7 KiB
Go

package restapi
import (
"net/http"
"github.com/gin-gonic/gin"
)
// withCORS returns a gin middleware that handles browser CORS preflight and
// attaches Access-Control-Allow-* response headers when the request's Origin
// is on the configured allow-list. Origins are compared exactly: scheme,
// host, and port must match. An empty allow-list disables the middleware —
// requests pass through untouched. Requests without an Origin header always
// pass through, the middleware only acts when a browser actually asks.
//
// The middleware mounts before the anti-abuse layer so OPTIONS preflights
// do not count against the rate-limit buckets for the eventual real call.
func withCORS(allowedOrigins []string) gin.HandlerFunc {
allowed := make(map[string]struct{}, len(allowedOrigins))
for _, origin := range allowedOrigins {
allowed[origin] = struct{}{}
}
if len(allowed) == 0 {
return func(c *gin.Context) { c.Next() }
}
return func(c *gin.Context) {
origin := c.GetHeader("Origin")
if origin == "" {
c.Next()
return
}
if _, ok := allowed[origin]; !ok {
c.Next()
return
}
c.Header("Access-Control-Allow-Origin", origin)
c.Header("Vary", "Origin")
c.Header("Access-Control-Allow-Credentials", "true")
if c.Request.Method == http.MethodOptions {
c.Header("Access-Control-Allow-Methods", "GET, POST, PUT, PATCH, DELETE, OPTIONS")
if reqHeaders := c.GetHeader("Access-Control-Request-Headers"); reqHeaders != "" {
c.Header("Access-Control-Allow-Headers", reqHeaders)
} else {
c.Header("Access-Control-Allow-Headers", "Content-Type, Authorization")
}
c.Header("Access-Control-Max-Age", "3600")
c.AbortWithStatus(http.StatusNoContent)
return
}
c.Next()
}
}