model: Fix direct access to database

Instead a database transaction has to be used. Each database interaction
should be wrapped into a transaction to make sure any possible change
(even side-effects) can be rolled back in case of errors.

2 files changed, 18 insertions, 3 deletions

diff --git a/model/recipes.go b/model/recipes.go
index fd8115f..324589a 100644
--- a/model/recipes.go
+++ b/model/recipes.go
@@ -1,7 +1,9 @@
 package model
 
 import (
+	"database/sql"
 	"errors"
+	"fmt"
 )
 
 type RecipesElement struct {
@@ -11,14 +13,18 @@ type RecipesElement struct {
 
 type Recipes []RecipesElement
 
-func (r *Recipes) Read() error {
+func (r *Recipes) Create(tx *sql.Tx) error {
+	return fmt.Errorf("Impossible to create a recipe list")
+}
+
+func (r *Recipes) Read(tx *sql.Tx) error {
 	if len(*r) != 0 {
 		return errors.New("Recipes has to contain zero elements for .Read()")
 	}
 
 	query := `SELECT id, title FROM recipes`
 
-	rows, err := db.Query(query)
+	rows, err := tx.Query(query)
 	if err != nil {
 		return err
 	}
@@ -36,6 +42,14 @@ func (r *Recipes) Read() error {
 	return nil
 }
 
+func (r *Recipes) Update(tx *sql.Tx) error {
+	return fmt.Errorf("Impossible to update a recipe list")
+}
+
+func (r *Recipes) Delete(tx *sql.Tx) error {
+	return fmt.Errorf("Impossible to delete a recipe list")
+}
+
 func RecipesTestData() Recipes {
 	return []RecipesElement{
 		{
diff --git a/view/recipes.go b/view/recipes.go
index bd4c72b..fe995b2 100644
--- a/view/recipes.go
+++ b/view/recipes.go
@@ -9,7 +9,8 @@ import (
 func RecipesRead(w http.ResponseWriter, r *http.Request) {
 	recipes := make(model.Recipes, 0)
 
-	err := recipes.Read()
+	var obj model.Object = &recipes
+	err := model.Transaction(obj.Read)
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return