From 7048d507ce1db4afd2af4aa82a6be51edcd3d7f2 Mon Sep 17 00:00:00 2001
From: Drew Bednar <drew@androiddrew.com>
Date: Sun, 23 Jun 2024 09:06:02 -0400
Subject: [PATCH] Finished tutorial

---
 go-web-app/.gitignore          |  3 +-
 go-web-app/gowiki/TestPage.txt |  2 +-
 go-web-app/gowiki/test.txt     |  1 -
 go-web-app/gowiki/wiki.go      | 83 ++++++++++++++++++++++++++++------
 4 files changed, 72 insertions(+), 17 deletions(-)

diff --git a/go-web-app/.gitignore b/go-web-app/.gitignore
index c4ad3b3..bcc6ba6 100644
--- a/go-web-app/.gitignore
+++ b/go-web-app/.gitignore
@@ -1 +1,2 @@
-gowiki/wiki
\ No newline at end of file
+gowiki/wiki
+gowiki/*.txt
\ No newline at end of file
diff --git a/go-web-app/gowiki/TestPage.txt b/go-web-app/gowiki/TestPage.txt
index 95b6a38..a5331a9 100644
--- a/go-web-app/gowiki/TestPage.txt
+++ b/go-web-app/gowiki/TestPage.txt
@@ -1 +1 @@
-This is a test page.
\ No newline at end of file
+This is my fixed test page
\ No newline at end of file
diff --git a/go-web-app/gowiki/test.txt b/go-web-app/gowiki/test.txt
index 9fc0ab5..e69de29 100644
--- a/go-web-app/gowiki/test.txt
+++ b/go-web-app/gowiki/test.txt
@@ -1 +0,0 @@
-This is a page
\ No newline at end of file
diff --git a/go-web-app/gowiki/wiki.go b/go-web-app/gowiki/wiki.go
index c8d752e..ad269b3 100644
--- a/go-web-app/gowiki/wiki.go
+++ b/go-web-app/gowiki/wiki.go
@@ -5,8 +5,15 @@ import (
 	"log"
 	"net/http"
 	"os"
+	"regexp"
 )
 
+// Template caching
+var templates = template.Must(template.ParseFiles("edit.html", "view.html"))
+
+// Validation to prevent abitrary paths
+var validPath = regexp.MustCompile("^/(edit|save|view)/([a-zA-Z0-9]+)$")
+
 // A wiki consists of a series of interconnected pages, each of which has a title and a body
 type Page struct {
 	Title string
@@ -20,6 +27,17 @@ func (p *Page) save() error {
 	return os.WriteFile(filename, p.Body, 0600)
 }
 
+// Not neccessary after makeHandler implemented this.
+
+// func getTitle(w http.ResponseWriter, r *http.Request) (string, error) {
+// 	m := validPath.FindStringSubmatch(r.URL.Path)
+// 	if m == nil {
+// 		http.NotFound(w, r)
+// 		return "", errors.New("invalid Page Title")
+// 	}
+// 	return m[2], nil // The title is the second subexpression
+// }
+
 // loadPage loads a Page from disk.
 // It takes the title of the page as an argument, reads the corresponding
 // file, and returns a pointer to a Page struct containing the title and body.
@@ -35,20 +53,41 @@ func loadPage(title string) (*Page, error) {
 }
 
 func renderTemplate(w http.ResponseWriter, tmpl string, p *Page) {
-	t, err := template.ParseFiles(tmpl + ".html")
+	// In efficient. No cacheing
+	// t, err := template.ParseFiles(tmpl + ".html")
+	// if err != nil {
+	// 	http.Error(w, err.Error(), http.StatusInternalServerError)
+	// 	return
+	// }
+	// err = t.Execute(w, p)
+
+	//With caching
+	err := templates.ExecuteTemplate(w, tmpl+".html", p)
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
-		return
 	}
-	err = t.Execute(w, p)
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
+}
+
+// Wraps a handler function, includes validation checks on titles
+func makeHandler(fn func(http.ResponseWriter, *http.Request, string)) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		m := validPath.FindStringSubmatch(r.URL.Path)
+		if m == nil {
+			http.NotFound(w, r)
+			return
+		}
+		fn(w, r, m[2])
 	}
 }
 
-func viewHandler(w http.ResponseWriter, r *http.Request) {
+func viewHandler(w http.ResponseWriter, r *http.Request, title string) {
 	// html := "<h1>%s</h1><div>%s</div>"
-	title := r.URL.Path[len("/view/"):]
+	// title := r.URL.Path[len("/view/"):]
+	// Not neccesary after makeHandler was implemented
+	// title, err := getTitle(w, r)
+	// if err != nil {
+	// 	return
+	// }
 	page, err := loadPage(title)
 	// fmt.Fprintf(w, html, page.Title, page.Body)
 	// t, _ := template.ParseFiles("view.html")
@@ -62,8 +101,13 @@ func viewHandler(w http.ResponseWriter, r *http.Request) {
 	renderTemplate(w, "view", page)
 }
 
-func editHandler(w http.ResponseWriter, r *http.Request) {
-	title := r.URL.Path[len("/edit/"):]
+func editHandler(w http.ResponseWriter, r *http.Request, title string) {
+	// title := r.URL.Path[len("/edit/"):]
+	// Not neccesary after makeHandler was implemented
+	// title, err := getTitle(w, r)
+	// if err != nil {
+	// 	return
+	// }
 	page, err := loadPage(title)
 	if err != nil {
 		page = &Page{Title: title}
@@ -82,11 +126,17 @@ func editHandler(w http.ResponseWriter, r *http.Request) {
 	renderTemplate(w, "edit", page)
 }
 
-func saveHandler(w http.ResponseWriter, r *http.Request) {
-	title := r.URL.Path[len("/save/"):]
+func saveHandler(w http.ResponseWriter, r *http.Request, title string) {
+	// title := r.URL.Path[len("/save/"):]
+	// Not neccesary after makeHandler was implemented
+	// title, err := getTitle(w, r)
+	// if err != nil {
+	// 	return
+	// }
 	body := r.FormValue("body")
 	p := &Page{Title: title, Body: []byte(body)}
 	err := p.save()
+
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
@@ -95,9 +145,14 @@ func saveHandler(w http.ResponseWriter, r *http.Request) {
 }
 
 func main() {
-	http.HandleFunc("/view/", viewHandler)
-	http.HandleFunc("/edit/", editHandler)
-	http.HandleFunc("/save/", saveHandler)
+	log.Printf("%s\n", templates.DefinedTemplates())
+	// Using function literal and closures to handle not found
+	// http.HandleFunc("/view/", viewHandler)
+	// http.HandleFunc("/edit/", editHandler)
+	// http.HandleFunc("/save/", saveHandler)
+	http.HandleFunc("/view/", makeHandler(viewHandler))
+	http.HandleFunc("/edit/", makeHandler(editHandler))
+	http.HandleFunc("/save/", makeHandler(saveHandler))
 
 	log.Println("Serving on: http://0.0.0.0:5001")
 	log.Fatal(http.ListenAndServe(":5001", nil))