owncast/router/middleware/headers.go

package middleware

import (
	"fmt"
	"net/http"
	"os"
	"strings"
)

// SetHeaders will set our global headers for web resources.
func SetHeaders(w http.ResponseWriter) {
	// When running automated browser tests we must allow `unsafe-eval` in our CSP
	// so we can explicitly add it only when needed.
	inTest := os.Getenv("BROWSER_TEST") == "true"
	unsafeEval := ""
	if inTest {
		unsafeEval = `'unsafe-eval'`
	}
	// Content security policy
	csp := []string{
		fmt.Sprintf("script-src 'self' %s 'sha256-B5bOgtE39ax4J6RqDE93TVYrJeLAdxDOJFtF3hoWYDw=' 'sha256-PzXGlTLvNFZ7et6GkP2nD3XuSaAKQVBSYiHzU2ZKm8o=' 'sha256-/wqazZOqIpFSIrNVseblbKCXrezG73X7CMqRSTf+8zw=' 'sha256-jCj2f+ICtd8fvdb0ngc+Hkr/ZnZOMvNkikno/XR6VZs='", unsafeEval),
		"worker-src 'self' blob:", // No single quotes around blob:
	}
	w.Header().Set("Content-Security-Policy", strings.Join(csp, "; "))
}