implement diff?f=&t= endpoint

WikiServer.go

@@ -139,6 +139,23 @@ func (this *WikiServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 			this.routeRecentChanges(w, r, pageNum)
 			return
 
+		} else if r.URL.Path == this.opts.ExpectBaseURL+"diff" {
+
+			fromRev, err := strconv.Atoi(r.URL.Query().Get("f"))
+			if err != nil {
+				this.serveErrorMessage(w, err)
+				return
+			}
+
+			toRev, err := strconv.Atoi(r.URL.Query().Get("t"))
+			if err != nil {
+				this.serveErrorMessage(w, err)
+				return
+			}
+
+			this.routeDiff(w, r, fromRev, toRev)
+			return
+
 		}
 
 	} else if r.Method == "POST" {

rDiff.go

@@ -0,0 +1,64 @@
+package yatwiki3
+
+import (
+	"bytes"
+	"database/sql"
+	"errors"
+	"fmt"
+	"html/template"
+	"net/http"
+
+	"code.ivysaur.me/yatwiki3/diff"
+)
+
+func (this *WikiServer) routeDiff(w http.ResponseWriter, r *http.Request, oldRev, newRev int) {
+	if oldRev > newRev {
+		oldRev, newRev = newRev, oldRev
+	}
+
+	oa, err := this.db.GetRevision(oldRev)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			this.serveErrorMessage(w, errors.New("Invalid revision selected"))
+			return
+		}
+
+		this.serveErrorMessage(w, err)
+		return
+	}
+
+	na, err := this.db.GetRevision(newRev)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			this.serveErrorMessage(w, errors.New("Invalid revision selected"))
+			return
+		}
+
+		this.serveErrorMessage(w, err)
+		return
+	}
+
+	if oa.TitleID != na.TitleID {
+		this.serveErrorMessage(w, fmt.Errorf("Preventing attempt to compare mismatched articles (%s ≠ %s)", oa.Title, na.Title))
+		return
+	}
+
+	b := bytes.Buffer{}
+	diff.HtmlDiff(string(oa.Body), string(na.Body), &b)
+
+	pto := DefaultPageTemplateOptions(this.opts)
+	pto.CurrentPageName = oa.Title
+	pto.CurrentPageIsArticle = true
+
+	pto.Content = template.HTML(
+		`<h2>` +
+			`Comparing ` + string(this.viewLink(oa.Title)) + ` versions ` +
+			`<a href="` + template.HTMLEscapeString(this.opts.ExpectBaseURL+`archive/`+fmt.Sprintf("%d", oa.ID)) + `">r` + fmt.Sprintf("%d", oa.ID) + `</a>` +
+			` - ` +
+			`<a href="` + template.HTMLEscapeString(this.opts.ExpectBaseURL+`archive/`+fmt.Sprintf("%d", na.ID)) + `">r` + fmt.Sprintf("%d", na.ID) + `</a>` +
+			`</h2>` +
+			`<pre>` + string(b.Bytes()) + `</pre>`,
+	)
+	this.servePageResponse(w, r, pto)
+	return
+}

rErrors.go

@@ -44,3 +44,7 @@ func (this *WikiServer) formatTimestamp(m int64) string {
 	// TODO add a more detailed timestamp on hover
 	return template.HTMLEscapeString(time.Unix(m, 0).In(this.loc).Format(this.opts.DateFormat))
 }
+
+func (this *WikiServer) viewLink(articleTitle string) template.HTML {
+	return template.HTML(`&quot;<a href="` + template.HTMLEscapeString(this.opts.ExpectBaseURL+`view/`+url.QueryEscape(articleTitle)) + `">` + template.HTMLEscapeString(articleTitle) + `</a>&quot;`)
+}