implement 'article index' page, better error handling

WikiServer.go

@@ -2,9 +2,12 @@ package yatwiki3
 
 import (
 	"database/sql"
+	"errors"
+	"fmt"
 	"html/template"
 	"log"
 	"net/http"
+	"net/url"
 	"strings"
 )
 
@@ -79,7 +82,32 @@ func (this *WikiServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	<li>[section=header]content[/section]</li>
 	<li>[html]raw html[/html]</li>
 </ul>`
-			this.servePageResponse(w, pto)
+			this.servePageResponse(w, r, pto)
+			return
+
+		} else if r.URL.Path == this.opts.ExpectBaseURL+"index" {
+			titles, err := this.db.ListTitles()
+			if err != nil {
+				this.serveInternalError(w, r, err)
+				return
+			}
+
+			totalRevs, err := this.db.TotalRevisions()
+			if err != nil {
+				this.serveInternalError(w, r, err)
+				return
+			}
+
+			content := fmt.Sprintf(`<h2>Article Index</h2><br><em>There are %d edits to %d pages.</em><br><br><ul>`, totalRevs, len(titles))
+			for _, title := range titles {
+				content += `<li><a href="` + template.HTMLEscapeString(this.opts.ExpectBaseURL+`view/`+url.QueryEscape(title)) + `">` + template.HTMLEscapeString(title) + `</a></li>`
+			}
+			content += `</ul>`
+
+			pto := DefaultPageTemplateOptions(this.opts)
+			pto.CurrentPageName = "Index"
+			pto.Content = template.HTML(content)
+			this.servePageResponse(w, r, pto)
 			return
 
 		} else if strings.HasPrefix(r.URL.Path, this.opts.ExpectBaseURL+"view/") {
@@ -91,6 +119,11 @@ func (this *WikiServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 			a, err := this.db.GetLatestVersion(articleTitle)
 			if err != nil {
+
+				if err == sql.ErrNoRows {
+					this.serveErrorHTMLMessage(w, this.noSuchArticleError(articleTitle))
+					return
+				}
 				this.serveErrorMessage(w, err)
 				return
 			}
@@ -103,7 +136,7 @@ func (this *WikiServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 			pto.Content = bcr.RenderHTML(string(a.Body))
 			pto.LoadCodeResources = bcr.CodePresent
 
-			this.servePageResponse(w, pto)
+			this.servePageResponse(w, r, pto)
 			return
 
 		}
@@ -111,30 +144,31 @@ func (this *WikiServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// No match? Add 'Page not found' to next session response, and redirect to homepage
-	http.Error(w, "Page not found", 404)
+	this.serveErrorMessage(w, errors.New("Page not found"))
 
-	/*
-		pto.SessionMessage = `Invalid request.`
-		//pto.CurrentPageIsArticle = true
-		//pto.CurrentPageName = "quotes/\"2017"
+}
 
-		bcr := NewBBCodeRenderer(this.opts.ExpectBaseURL)
-		pto.Content = bcr.RenderHTML(`[h]Hello World[/h] this content is [b]bold[/b] <script>alert("hi");</script>`)
-
-		this.servePageResponse(w, pto)
-	*/
+func (this *WikiServer) noSuchArticleError(title string) template.HTML {
+	return template.HTML(`No such article exists. <a href="` + this.opts.ExpectBaseURL + `modify/` + template.HTMLEscapeString(url.QueryEscape(title)) + `">Click here</a> to create it.`)
 }
 
 func (this *WikiServer) serveErrorMessage(w http.ResponseWriter, message error) {
-	if message == sql.ErrNoRows {
-		// 404 not found
-	}
-
-	// TODO Add error message to session response, and redirect to homepage
-	http.Error(w, message.Error(), 500)
+	this.serveErrorHTMLMessage(w, template.HTML(template.HTMLEscapeString(message.Error())))
 }
 
-func (this *WikiServer) servePageResponse(w http.ResponseWriter, pto *pageTemplateOptions) {
+func (this *WikiServer) serveInternalError(w http.ResponseWriter, r *http.Request, e error) {
+	log.Printf("Internal error from %s while accessing %s(%s): %s", r.RemoteAddr, r.Method, r.URL.Path, e.Error())
+	http.Error(w, "An internal error occurred. Please ask an administrator to check the log file.", 500)
+}
+
+func (this *WikiServer) serveErrorHTMLMessage(w http.ResponseWriter, msg template.HTML) {
+	w.Header().Set("Location", this.opts.ExpectBaseURL+"view/"+url.QueryEscape(this.opts.DefaultPage)+"?error="+url.QueryEscape(string(msg)))
+	w.WriteHeader(302) // moved (not permanently)
+}
+
+func (this *WikiServer) servePageResponse(w http.ResponseWriter, r *http.Request, pto *pageTemplateOptions) {
+	pto.SessionMessage = template.HTML(r.URL.Query().Get("error")) // FIXME reflected XSS (although Chrome automatically blocks it..)
+
 	err := this.pageTmp.Execute(w, pto)
 	if err != nil {
 		log.Println(err.Error())