handlers

**Introduction** Crema uses standard function handler of the type http.HandlerFunc which takes an http.ResponseWriter and an http.Request as its arguments. For example from [[ http://phabricator.hexavara.com/w/crema/routing/ | this endpoints ]], we can define a handler ``` func hello(w http.ResponseWriter, r *http.Request) { w.Write([]byte("Hello World!")) } ``` **Using Generic Handler** Crema provides us with a generic handlers to create a basic application of CRUD faster. As an example, we'll begin by creating the CRUD endpoints for a resource named **users**: ``` server.AddRoutes(http.MethodGet, "/users", crema.MakeGenericGetHandler(GetUser)) server.AddRoutes(http.MethodPost, "/users", crema.MakeGenericPostHandler(PostUser)) server.AddRoutes(http.MethodPut, "/users/{id}", crema.MakeGenericPutHandler(PutUser)) server.AddRoutes(http.MethodDelete, "/users/{id}", crema.MakeGenericDeleteHandler(DeleteUser)) ``` Then we set up the handler corresponding each endpoint. 1. GET users ``` func GetUser(conditions map[string]string) (*sql.Rows, error) { q := crema.GetGenericSelectQuery("users", conditions, "id") return crema.ExecuteQuery(q.QueryString) } ``` 2. POST users ``` func PostUser(tx *sql.Tx, values map[string]string) *sql.Row { q := crema.GetGenericInsertQuery("users", values) return crema.ExecuteQueryRow(tx, q.QueryString) } ``` 3. UPDATE users ``` func PutUser(tx *sql.Tx, values map[string]string) (sql.Result, error) { q := crema.GetGenericUpdateQuery("users", values, "id") return crema.ExecuteNonQuery(q.QueryString) } ``` 4. DELETE users ``` func DeleteUser(tx *sql.Tx, conditions map[string]string) (sql.Result, error) { q := crema.GetGenericDeleteQuery("users", conditions, "id") return crema.ExecuteNonQuery(q.QueryString) } ``` **Explanation** UPDATED SOON