Simplify shortpath code

http.go

@@ -226,7 +226,7 @@ func (a *goBlog) servePostsAliasesRedirects() http.HandlerFunc {
 		select 'post', status, 200 from posts where path = @path
 		union all
 		-- short paths
-		select 'alias', path, 301 from shortpath where printf('/s/`+"%"+`x', id) = @path
+		select 'alias', path, 301 from shortpath where printf('/s/%x', id) = @path
 		union all
 		-- post aliases
 		select 'alias', path, 302 from post_parameters where parameter = 'aliases' and value = @path

shortPath.go

@@ -3,49 +3,38 @@ package main
 import (
 	"database/sql"
 	"errors"
-	"fmt"
 )
 
 func (db *database) shortenPath(p string) (string, error) {
 	if p == "" {
 		return "", errors.New("empty path")
 	}
-	idi, err, _ := db.sp.Do(p, func() (interface{}, error) {
-		id := db.getShortPathID(p)
-		if id == -1 {
-			_, err := db.exec("insert or ignore into shortpath (path) values (@path)", sql.Named("path", p))
-			if err != nil {
-				return nil, err
-			}
-			id = db.getShortPathID(p)
+	spi, err, _ := db.sp.Do(p, func() (interface{}, error) {
+		// Check if already cached
+		if spi, ok := db.spc.Load(p); ok {
+			return spi.(string), nil
 		}
-		return id, nil
+		// Insert in case it isn't shortened yet
+		_, err := db.exec("insert or ignore into shortpath (path) values (@path)", sql.Named("path", p))
+		if err != nil {
+			return nil, err
+		}
+		// Query short path
+		row, err := db.queryRow("select printf('/s/%x', id) from shortpath where path = @path", sql.Named("path", p))
+		if err != nil {
+			return nil, err
+		}
+		var sp string
+		err = row.Scan(&sp)
+		if err != nil {
+			return nil, err
+		}
+		// Cache result
+		db.spc.Store(p, sp)
+		return sp, nil
 	})
 	if err != nil {
 		return "", err
 	}
-	id := idi.(int)
-	if id == -1 {
-		return "", errors.New("failed to retrieve short path for " + p)
-	}
-	return fmt.Sprintf("/s/%x", id), nil
-}
-
-func (db *database) getShortPathID(p string) (id int) {
-	if p == "" {
-		return -1
-	}
-	if idi, ok := db.spc.Load(p); ok {
-		return idi.(int)
-	}
-	row, err := db.queryRow("select id from shortpath where path = @path", sql.Named("path", p))
-	if err != nil {
-		return -1
-	}
-	err = row.Scan(&id)
-	if err != nil {
-		return -1
-	}
-	db.spc.Store(p, id)
-	return id
+	return spi.(string), nil
 }