make sure env vars are expanded in http req headers, refactor middleware

lib/gateway/gateway.go

@@ -5,6 +5,7 @@ import (
 	"io"
 	"net/http"
 	"net/url"
+	"os"
 	"strings"
 	"sync"
 
@@ -147,13 +148,15 @@ func (g *Gateway) GetUrl(urlStr string, headers ...string) (string, error) {
 	g.DomainHeaders.Range(func(key, value any) bool {
 		parsed, _ := url.Parse(urlStr)
 		if glob.Glob(key.(string), parsed.Hostname()) {
-			tempHeaders = append(tempHeaders, value.(string))
+			header := os.ExpandEnv(value.(string))
+			tempHeaders = append(tempHeaders, header)
 		}
 		return true
 	})
 
 	for _, header := range headers {
 		if strings.TrimSpace(header) != "" {
+			header = os.ExpandEnv(header)
 			tempHeaders = append(tempHeaders, header)
 		}
 	}

lib/gateway/middleware.go

@@ -52,7 +52,7 @@ func verifyFileTypeHandler(g *Gateway, link string) error {
 	}
 
 	allowedFileNames := []string{"checksums.txt", "checksums.sha256.txt", "checksums.sha512.txt", "sha256sum", "sha512sum"}
-	allowedExts := []string{".yaml", ".yml", ".txt", ".sha256", ".sha512"}
+	allowedExts := []string{".yaml", ".yml", ".txt", ".sha256", ".sha512", ".json", ".js"}
 
 	for _, name := range allowedFileNames {
 		if strings.EqualFold(baseName, name) {