Add explorer liquidity access and live route proxies

backend/api/rest/routes_proxy.go

@@ -0,0 +1,57 @@
+package rest
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"os"
+	"strings"
+)
+
+func (s *Server) handleRouteDecisionTree(w http.ResponseWriter, r *http.Request) {
+	s.proxyRouteTreeEndpoint(w, r, "/api/v1/routes/tree")
+}
+
+func (s *Server) handleRouteDepth(w http.ResponseWriter, r *http.Request) {
+	s.proxyRouteTreeEndpoint(w, r, "/api/v1/routes/depth")
+}
+
+func (s *Server) proxyRouteTreeEndpoint(w http.ResponseWriter, r *http.Request, path string) {
+	if r.Method != http.MethodGet {
+		writeMethodNotAllowed(w)
+		return
+	}
+
+	baseURL := strings.TrimSpace(firstNonEmptyEnv(
+		"TOKEN_AGGREGATION_API_BASE",
+		"TOKEN_AGGREGATION_URL",
+		"TOKEN_AGGREGATION_BASE_URL",
+	))
+	if baseURL == "" {
+		writeError(w, http.StatusServiceUnavailable, "service_unavailable", "token aggregation api base url is not configured")
+		return
+	}
+
+	target, err := url.Parse(strings.TrimRight(baseURL, "/"))
+	if err != nil {
+		writeError(w, http.StatusBadGateway, "bad_gateway", fmt.Sprintf("invalid token aggregation api base url: %v", err))
+		return
+	}
+
+	proxy := httputil.NewSingleHostReverseProxy(target)
+	proxy.ErrorHandler = func(rw http.ResponseWriter, req *http.Request, proxyErr error) {
+		writeError(rw, http.StatusBadGateway, "bad_gateway", fmt.Sprintf("route tree proxy failed for %s: %v", path, proxyErr))
+	}
+
+	proxy.ServeHTTP(w, r)
+}
+
+func firstNonEmptyEnv(keys ...string) string {
+	for _, key := range keys {
+		if value := strings.TrimSpace(os.Getenv(key)); value != "" {
+			return value
+		}
+	}
+	return ""
+}