Init

main.go

@@ -0,0 +1,116 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"os"
+	"regexp"
+	"strings"
+)
+
+func replaceHref(v any, pattern, replacement, suffix string) any {
+	re := regexp.MustCompile(regexp.QuoteMeta(pattern) + `[^/]+/`)
+
+	switch val := v.(type) {
+	case map[string]any:
+		for k, v2 := range val {
+			if k == "href" {
+				if s, ok := v2.(string); ok && strings.Contains(s, pattern) {
+					newHref := re.ReplaceAllString(s, replacement+suffix+"/")
+					val[k] = newHref
+				}
+			} else {
+				val[k] = replaceHref(v2, pattern, replacement, suffix)
+			}
+		}
+	case []any:
+		for i, v2 := range val {
+			val[i] = replaceHref(v2, pattern, replacement, suffix)
+		}
+	}
+	return v
+}
+
+func handler(w http.ResponseWriter, r *http.Request) {
+	upstream := os.Getenv("UPSTREAM_URL")
+	pattern := os.Getenv("HREF_PATTERN")
+	replacement := os.Getenv("HREF_REPLACEMENT")
+	defaultSuffix := os.Getenv("DEFAULT_SUFFIX")
+
+	for k, v := range map[string]string{
+		"UPSTREAM_URL":     upstream,
+		"HREF_PATTERN":     pattern,
+		"HREF_REPLACEMENT": replacement,
+		"DEFAULT_SUFFIX":   defaultSuffix,
+	} {
+		if v == "" {
+			errMsg := fmt.Sprintf("Missing required environment variable: %s", k)
+			log.Fatal("❌ " + errMsg)
+		}
+	}
+
+	suffix := r.Header.Get("X-Issuer-Suffix")
+	if suffix == "" {
+		suffix = defaultSuffix
+	}
+
+	target := upstream + r.URL.RequestURI()
+	log.Printf("→ Fetching %s (suffix=%s)", target, suffix)
+
+	resp, err := http.Get(target)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusBadGateway)
+		return
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	var data any
+	if err := json.Unmarshal(body, &data); err != nil {
+		for k, v := range resp.Header {
+			if len(v) > 0 {
+				w.Header().Set(k, v[0])
+			}
+		}
+		w.WriteHeader(resp.StatusCode)
+		w.Write(body)
+		return
+	}
+
+	data = replaceHref(data, pattern, replacement, suffix)
+	modified, _ := json.MarshalIndent(data, "", "  ")
+
+	for k, v := range resp.Header {
+		if strings.ToLower(k) == "content-length" {
+			continue
+		}
+		if len(v) > 0 {
+			w.Header().Set(k, v[0])
+		}
+	}
+	w.Header().Set("Access-Control-Allow-Origin", "*")
+	w.Header().Set("Cache-Control", "no-store")
+	w.Header().Set("X-Content-Type-Options", "nosniff")
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+
+	w.WriteHeader(resp.StatusCode)
+	w.Write(modified)
+}
+
+func main() {
+	port := os.Getenv("PORT")
+	if port == "" {
+		port = "8080"
+	}
+	http.HandleFunc("/.well-known/webfinger", handler)
+	log.Printf("✅ Listening on :%s", port)
+	log.Fatal(http.ListenAndServe(":"+port, nil))
+}