Granularise modify() so it won't check/parse both

funcs.go

@@ -1,12 +1,22 @@
 package main
 
 import (
+	"html/template"
 	"io/ioutil"
 	"log"
 	"os"
 	"strings"
 )
 
+// parseIndex parses the index template and returns a template struct.
+func (s server) parseIndex() {
+	tmpl, err := template.ParseFiles(*flagIndex)
+	if err != nil {
+		log.Fatal(err)
+	}
+	s.index = tmpl
+}
+
 // List parses the list of members, appends the data to a slice of type list,
 // then returns the slice
 func (s server) parseList() {
@@ -26,32 +36,35 @@ func link(l string) string {
 	return "<a href='https://" + l + "'>" + l + "</a>"
 }
 
-// Modify returns true if the index and ring list have been modified since last
-// read
-func (s server) modify() bool {
-	members, err := os.Stat(*flagMembers)
-	if err != nil {
-		log.Fatalln(err)
+// Modify takes arguments "index" or "ring" and returns true if either have been
+// modified since last read
+func (s server) modify(a string) bool {
+	if a == "ring" {
+		members, err := os.Stat(*flagMembers)
+		if err != nil {
+			log.Fatalln(err)
+		}
+		curRingModTime := members.ModTime().Unix()
+		if s.ringModTime == 0 {
+			s.ringModTime = curRingModTime
+		} else if s.ringModTime < curRingModTime {
+			return true
+		}
+		return false
+	} else if a == "index" {
+		index, err := os.Stat(*flagIndex)
+		if err != nil {
+			log.Fatalln(err)
+		}
+		curIndexModTime := index.ModTime().Unix()
+		if s.indexModTime == 0 {
+			s.indexModTime = curIndexModTime
+		} else if s.indexModTime < curIndexModTime {
+			return true
+		}
+		return false
+	} else {
+		log.Fatalln("Please call modify() with argument of either \"index\" or \"ring\"")
 	}
-	index, err := os.Stat(*flagIndex)
-	if err != nil {
-		log.Fatalln(err)
-	}
-
-	curRingModTime := members.ModTime().Unix()
-	curIndexModTime := index.ModTime().Unix()
-
-	if s.ringModTime == 0 {
-		s.ringModTime = curRingModTime
-	} else if s.ringModTime < curRingModTime {
-		return true
-	}
-
-	if s.indexModTime == 0 {
-		s.indexModTime = curIndexModTime
-	} else if s.indexModTime < curIndexModTime {
-		return true
-	}
-
-	return false
+	return true
 }

handlers.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"html/template"
-	"log"
 	"math/rand"
 	"net/http"
 	"time"
@@ -10,8 +9,10 @@ import (
 
 // Serves the webpage created by createRoot()
 func (s server) root(writer http.ResponseWriter, request *http.Request) {
-	if s.modify() {
+	if s.modify("ring") {
 		s.parseList()
+	} else if s.modify("index") {
+		s.parseIndex()
 	}
 	var table string
 	for _, member := range s.ring {
@@ -20,19 +21,13 @@ func (s server) root(writer http.ResponseWriter, request *http.Request) {
 		table = table + "    <td>" + link(member.url) + "</td>\n"
 		table = table + "  </tr>\n"
 	}
-
-	tmpl, err := template.ParseFiles(*flagIndex)
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	tmpl.Execute(writer, template.HTML(table))
+	s.index.Execute(writer, template.HTML(table))
 }
 
 // Redirects the visitor to the next member, wrapping around the list if the
 // next would be out-of-bounds
 func (s server) next(writer http.ResponseWriter, request *http.Request) {
-	if s.modify() {
+	if s.modify("ring") {
 		s.parseList()
 	}
 	host := request.URL.Query().Get("host")
@@ -59,7 +54,7 @@ func (s server) next(writer http.ResponseWriter, request *http.Request) {
 // Redirects the visitor to the previous member, wrapping around the list if the
 // next would be out-of-bounds
 func (s server) previous(writer http.ResponseWriter, request *http.Request) {
-	if s.modify() {
+	if s.modify("ring") {
 		s.parseList()
 	}
 	host := request.URL.Query().Get("host")
@@ -83,7 +78,7 @@ func (s server) previous(writer http.ResponseWriter, request *http.Request) {
 
 // Redirects the visitor to a random member
 func (s server) random(writer http.ResponseWriter, request *http.Request) {
-	if s.modify() {
+	if s.modify("ring") {
 		s.parseList()
 	}
 	rand.Seed(time.Now().Unix())

main.go

@@ -3,6 +3,7 @@ package main
 import (
 	_ "embed"
 	"fmt"
+	"html/template"
 	"log"
 	"net/http"
 
@@ -16,7 +17,7 @@ type ring struct {
 
 type server struct {
 	ring         []ring
-	index        string
+	index        *template.Template
 	ringModTime  int64
 	indexModTime int64
 }
@@ -53,4 +54,5 @@ func (s server) init() {
 	fmt.Println("Looking for members in", *flagMembers)
 	s.parseList()
 	fmt.Println("Building homepage with", *flagIndex)
+	s.parseIndex()
 }