From b9bb17044a8c2b47c7e96660e27ab645f82bec9d Mon Sep 17 00:00:00 2001
From: Mitch Riedstra <mitch@riedstra.us>
Date: Thu, 4 Mar 2021 19:44:02 -0500
Subject: Further refactoring.

---
 cmd/web/util.go | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)
 create mode 100644 cmd/web/util.go

(limited to 'cmd/web/util.go')

diff --git a/cmd/web/util.go b/cmd/web/util.go
new file mode 100644
index 0000000..1252c66
--- /dev/null
+++ b/cmd/web/util.go
@@ -0,0 +1,89 @@
+package main
+
+import (
+	"io"
+	"os"
+	"net/http"
+	"net"
+	"strings"
+)
+
+func UnauthorizedIfNotLocal(h http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if !isLocal(r.RemoteAddr) {
+			http.Error(w, "Unauthorized", http.StatusUnauthorized)
+			Logger.Printf("Unauthorized request from: %s for %s",
+				r.RemoteAddr, r.RequestURI)
+			return 
+		}
+		h.ServeHTTP(w, r)
+	})
+}
+
+func isLocal(addr string) bool {
+	_, localNet, _ := net.ParseCIDR("127.0.0.1/8")
+	return localNet.Contains(net.ParseIP(strings.Split(addr, ":")[0]))
+}
+
+// getHostIP attempts to guess the IP address of the current machine and
+// returns that. Simply bails at the first non sane looking IP and returns it.
+// Not ideal but it should work well enough most of the time
+func getHostIP() string {
+	iFaces, err := net.Interfaces()
+	if err != nil {
+		return "127.0.0.1"
+	}
+
+	// RFC 3927
+	_, ipv4LinkLocal, _ := net.ParseCIDR("169.254.0.0/16")
+
+	for _, iFace := range iFaces {
+		addrs, err := iFace.Addrs()
+		if err != nil {
+			return "127.0.0.1"
+		}
+
+		for _, a := range addrs {
+			n, ok := a.(*net.IPNet)
+			if !ok {
+				continue
+			}
+
+			if n.IP.To4() != nil && !n.IP.IsLoopback() && !ipv4LinkLocal.Contains(n.IP.To4()) {
+				return n.IP.String()
+			}
+		}
+	}
+
+	return "127.0.0.1"
+}
+
+func getPort() string {
+	s := strings.Split(Listen, ":")
+
+	if len(s) != 2 {
+		return Listen
+	}
+
+	return s[1]
+}
+
+func serveSelf(w http.ResponseWriter, r *http.Request) {
+	s, err := os.Executable()
+	if err != nil {
+		Logger.Println("While trying to get my executable path: ", err)
+		http.Error(w, "Internal server error", http.StatusInternalServerError)
+		return
+	}
+
+	fh, err := os.Open(s)
+	if err != nil {
+		Logger.Println("While opening my own executable for reading: ", err)
+		http.Error(w, "Internal server error", http.StatusInternalServerError)
+		return
+	}
+
+	_, err = io.Copy(w, fh)
+	fh.Close()
+	return
+}
-- 
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