From daaddbb56bdb480256e151aebbfaa7f04264125c Mon Sep 17 00:00:00 2001
From: ChaoticByte <contact@chaoticbyte.net>
Date: Tue, 27 Aug 2024 14:48:46 +0200
Subject: [PATCH] Preload all entries into memory on server startup

---
 database.go | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 main.go     | 31 +++++++++----------------------
 2 files changed, 62 insertions(+), 22 deletions(-)
 create mode 100644 database.go

diff --git a/database.go b/database.go
new file mode 100644
index 0000000..40b226d
--- /dev/null
+++ b/database.go
@@ -0,0 +1,53 @@
+package main
+
+import (
+	"io/fs"
+	"log"
+	"os"
+	"strings"
+)
+
+type Entry struct {
+	Name string		// from filename
+	Content string	// from content
+}
+
+type Database struct {
+	Entries []Entry
+}
+
+func (db *Database) TOC() []string {
+	var names []string
+	for _, e := range db.Entries {
+		names = append(names, e.Name)
+	}
+	return names
+}
+
+func (db *Database) Entry(name string) string {
+	// returns empty string if not found
+	result := ""
+	for _, e := range db.Entries {
+		if e.Name == name {
+			result = e.Content
+		}
+	}
+	return result
+}
+
+func BuildDB(directory string) Database {
+	logger := log.Default()
+	logger.Println("Building database")
+	var entries []Entry
+	// get files in directory and read them
+	directory = strings.TrimRight(directory, "/") // we don't need that last / -> if '/' is used as directory, you are dumb.
+	entriesDirFs := os.DirFS(directory)
+	files, err := fs.Glob(entriesDirFs, "*")
+	if err != nil { logger.Panicln(err) }
+	for _, f := range files {
+		contentB, err := os.ReadFile(directory + "/" + f)
+		if err != nil { logger.Panicln(err) }
+		entries = append(entries, Entry{Name: f, Content: string(contentB)})
+	}
+	return Database{Entries: entries}
+}
diff --git a/main.go b/main.go
index 93b8ff2..5fd7fd7 100644
--- a/main.go
+++ b/main.go
@@ -2,7 +2,6 @@ package main
 
 import (
 	"html/template"
-	"io/fs"
 	"log"
 	"net/http"
 	"os"
@@ -11,6 +10,7 @@ import (
 
 var logger *log.Logger
 var appTemplate *template.Template = template.New("app")
+var db Database
 
 type TemplateData struct {
 	TOC []string
@@ -21,23 +21,10 @@ type TemplateData struct {
 
 func loadTemplate() {
 	data, err := os.ReadFile(TemplateFile)
-	if err != nil { logger.Panic(err) }
+	if err != nil { logger.Panicln(err) }
 	appTemplate.Parse(string(data))
 }
 
-func getTOC() []string {
-	entriesDirFs := os.DirFS(EntriesDirectory)
-	m, err := fs.Glob(entriesDirFs, "*")
-	if err != nil { logger.Panic(err) }
-	return m
-}
-
-func getEntry(name string) (string, error) {
-	data, err := os.ReadFile(strings.TrimRight(EntriesDirectory, "/") + "/" + name)
-	if err != nil { return "", err }
-	return string(data), err
-}
-
 func handleApplication(w http.ResponseWriter, req *http.Request) {
 	var entry string
 	var err error
@@ -50,13 +37,11 @@ func handleApplication(w http.ResponseWriter, req *http.Request) {
 			return
 		}
 		// load entry
-		entry, err = getEntry(entryName)
-		if err != nil {
-			logger.Println("Couldn't open entry", entryName)
-			w.WriteHeader(http.StatusNotFound)
-		}
+		entry = db.Entry(entryName)
 	}
-	err = appTemplate.ExecuteTemplate(w, "app", TemplateData{TOC: getTOC(), Entry: entry, Title: MainTitle, EntryTitle: entryName})
+	err = appTemplate.ExecuteTemplate(
+		w, "app",
+		TemplateData{TOC: db.TOC(), Entry: entry, Title: MainTitle, EntryTitle: entryName})
 	if err != nil { logger.Println(err) }
 }
 
@@ -65,6 +50,8 @@ func main() {
 	logger = log.Default()
 	// load template
 	loadTemplate()
+	// build db
+	db = BuildDB(EntriesDirectory)
 	// handle static files
 	staticHandler := http.StripPrefix("/static/", http.FileServer(http.Dir(StaticDirectory)))
 	http.Handle("/static/", staticHandler)
@@ -73,5 +60,5 @@ func main() {
 	// start server
 	logger.Println("Starting server on", ServerListen)
 	err := http.ListenAndServe(ServerListen, nil)
-	if err != nil { logger.Panic(err) }
+	if err != nil { logger.Panicln(err) }
 }