Resolve issue with returning a lower number of servers, add auth to reload

http.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"github.com/jmcvetta/randutil"
+	"github.com/spf13/viper"
 	"net"
 	"net/http"
 	"net/url"
@@ -117,6 +118,20 @@ func redirectHandler(w http.ResponseWriter, r *http.Request) {
 }
 
 func reloadHandler(w http.ResponseWriter, r *http.Request) {
+	token := r.Header.Get("Authorization")
+
+	if token == "" || !strings.HasPrefix(token, "Bearer") || !strings.Contains(token, " ") {
+		w.WriteHeader(http.StatusUnauthorized)
+		return
+	}
+
+	token = token[strings.Index(token, " ")+1:]
+
+	if token != viper.GetString("reloadToken") {
+		w.WriteHeader(http.StatusUnauthorized)
+		return
+	}
+
 	reloadConfig()
 
 	w.WriteHeader(http.StatusOK)

main.go

@@ -79,14 +79,20 @@ type ServerConfig struct {
 
 var (
 	configFlag = flag.String("config", "", "configuration file path")
+	flagDebug  = flag.Bool("debug", false, "Enable debug logging")
 )
 
 func main() {
 	flag.Parse()
 
+	if *flagDebug {
+		log.SetLevel(log.DebugLevel)
+	}
+
 	viper.SetDefault("bind", ":8080")
 	viper.SetDefault("cacheSize", 1024)
 	viper.SetDefault("topChoices", 3)
+	viper.SetDefault("reloadKey", randSeq(32))
 
 	viper.SetConfigName("dlrouter")        // name of config file (without extension)
 	viper.SetConfigType("yaml")            // REQUIRED if the config file does not have the extension in the name

servers.go

@@ -7,6 +7,7 @@ import (
 	"math"
 	"net"
 	"net/http"
+	"net/url"
 	"runtime"
 	"sort"
 	"strings"
@@ -33,7 +34,7 @@ type Server struct {
 }
 
 func (server *Server) checkStatus() {
-	req, err := http.NewRequest(http.MethodGet, "https://"+server.Host+"/"+strings.TrimLeft(server.Path, "/"), nil)
+	req, err := http.NewRequest(http.MethodGet, "http://"+server.Host+"/"+strings.TrimLeft(server.Path, "/"), nil)
 
 	req.Header.Set("User-Agent", "ArmbianRouter/1.0 (Go "+runtime.Version()+")")
 
@@ -72,6 +73,35 @@ func (server *Server) checkStatus() {
 	}
 
 	if res.StatusCode == http.StatusOK || res.StatusCode == http.StatusMovedPermanently || res.StatusCode == http.StatusFound || res.StatusCode == http.StatusNotFound {
+		if res.StatusCode == http.StatusMovedPermanently || res.StatusCode == http.StatusFound {
+			location := res.Header.Get("Location")
+
+			responseFields["url"] = location
+
+			log.WithFields(responseFields).Debug("Server responded with redirect")
+
+			newUrl, err := url.Parse(location)
+
+			if err != nil {
+				if server.Available {
+					log.WithFields(responseFields).Warning("Server returned invalid url")
+					server.Available = false
+					server.LastChange = time.Now()
+				}
+				return
+			}
+
+			if newUrl.Scheme == "https" {
+				if server.Available {
+					responseFields["url"] = location
+					log.WithFields(responseFields).Warning("Server returned https url for http request")
+					server.Available = false
+					server.LastChange = time.Now()
+				}
+				return
+			}
+		}
+
 		if !server.Available {
 			server.Available = true
 			server.LastChange = time.Now()
@@ -161,9 +191,15 @@ func (s ServerList) Closest(ip net.IP) (*Server, float64, error) {
 			return c[i].Distance < c[j].Distance
 		})
 
-		choices := make([]randutil.Choice, topChoices)
+		choiceCount := topChoices
 
-		for i, item := range c[0:topChoices] {
+		if len(c) < topChoices {
+			choiceCount = len(c)
+		}
+
+		choices := make([]randutil.Choice, choiceCount)
+
+		for i, item := range c[0:choiceCount] {
 			if item.Server == nil {
 				continue
 			}

util.go

@@ -0,0 +1,13 @@
+package main
+
+import "math/rand"
+
+var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+
+func randSeq(n int) string {
+	b := make([]rune, n)
+	for i := range b {
+		b[i] = letters[rand.Intn(len(letters))]
+	}
+	return string(b)
+}