Optimice the partial queries

admin.go

@@ -23,7 +23,7 @@ func deleteHandler(coll *mgo.Collection, url string) func(http.ResponseWriter, *
 
 		// cutre hack: /delete/ and /delnew/ have the same lenght:
 		id := bson.ObjectIdHex(r.URL.Path[len("/delete/"):])
-		books, err := GetBook(coll, bson.M{"_id": id})
+		books, _, err := GetBook(coll, bson.M{"_id": id})
 		if err != nil {
 			http.NotFound(w, r)
 			return
@@ -47,7 +47,7 @@ func editHandler(coll *mgo.Collection) func(http.ResponseWriter, *http.Request)
 			return
 		}
 		id := bson.ObjectIdHex(r.URL.Path[len("/edit/"):])
-		books, err := GetBook(coll, bson.M{"_id": id})
+		books, _, err := GetBook(coll, bson.M{"_id": id})
 		if err != nil {
 			http.NotFound(w, r)
 			return
@@ -122,10 +122,10 @@ func newHandler(coll *mgo.Collection) func(http.ResponseWriter, *http.Request) {
 			return
 		}
 
-		res, _ := GetBook(coll, bson.M{})
+		res, num, _ := GetBook(coll, bson.M{})
 		var data newData
 		data.S = GetStatus(w, r)
-		data.Found = len(res)
+		data.Found = num
 		data.Books = res
 		loadTemplate(w, "new", data)
 	}
@@ -140,7 +140,7 @@ func storeHandler(newColl, coll *mgo.Collection) func(http.ResponseWriter, *http
 		}
 
 		id := bson.ObjectIdHex(r.URL.Path[len("/store/"):])
-		books, err := GetBook(newColl, bson.M{"_id": id})
+		books, _, err := GetBook(newColl, bson.M{"_id": id})
 		if err != nil {
 			http.NotFound(w, r)
 			return

database.go

@@ -28,12 +28,34 @@ type Book struct {
 	Keywords    []string
 }
 
-func GetBook(coll *mgo.Collection, query bson.M) ([]Book, error) {
+/* optional parameters: length and start index
-	var books []Book
+ * 
-	err := coll.Find(query).All(&books)
+ * Returns: list of books, number found and err
+ */
+func GetBook(coll *mgo.Collection, query bson.M, r ...int) (books []Book, num int, err error) {
+	var start, length int
+	if len(r) > 0 {
+		length = r[0]
+		if len(r) > 1 {
+			start = r[1]
+		}
+	}
+	q := coll.Find(query)
+	num, err = q.Count()
+	if err != nil {
+		return
+	}
+	if start != 0 {
+		q = q.Skip(start)
+	}
+	if length != 0 {
+		q = q.Limit(length)
+	}
+
+	err = q.All(&books)
 	for i, b := range books {
 		books[i].Id = bson.ObjectId(b.Id).Hex()
 	}
-	return books, err
+	return
 
 }

search.go

@@ -47,27 +47,22 @@ func searchHandler(coll *mgo.Collection) func(http.ResponseWriter, *http.Request
 			return
 		}
 		req := strings.Join(r.Form["q"], " ")
-		res, _ := GetBook(coll, buildQuery(req))
-
 		page := 0
 		if len(r.Form["p"]) != 0 {
 			page, err = strconv.Atoi(r.Form["p"][0])
-			if err != nil || len(res) < ITEMS_PAGE*page {
+			if err != nil {
 				page = 0
 			}
 		}
+		res, num, _ := GetBook(coll, buildQuery(req), ITEMS_PAGE, page)
 
 		var data searchData
 		data.S = GetStatus(w, r)
 		data.S.Search = req
-		data.Found = len(res)
+		data.Books = res
-		if len(res) > ITEMS_PAGE*(page+1) {
+		data.Found = num
-			data.Books = res[ITEMS_PAGE*page : ITEMS_PAGE*(page+1)]
-		} else {
-			data.Books = res[ITEMS_PAGE*page:]
-		}
 		data.Page = page + 1
-		if len(res) > (page+1)*ITEMS_PAGE {
+		if num > (page+1)*ITEMS_PAGE {
 			data.Next = "/search/?q=" + req + "&p=" + strconv.Itoa(page+1)
 		}
 		if page > 0 {

trantor.go

@@ -66,7 +66,7 @@ func bookHandler(coll *mgo.Collection) func(http.ResponseWriter, *http.Request)
 	return func(w http.ResponseWriter, r *http.Request) {
 		var data bookData
 		data.S = GetStatus(w, r)
-		books, err := GetBook(coll, bson.M{"title": r.URL.Path[len("/book/"):]})
+		books, _, err := GetBook(coll, bson.M{"title": r.URL.Path[len("/book/"):]})
 		if err != nil || len(books) == 0 {
 			http.NotFound(w, r)
 			return