package common // WhereClause is a struct representing a where clause. // This is made to easily create WHERE clauses from parameters passed from a request. type WhereClause struct { Clause string Params []interface{} useOr bool } // Where adds a new WHERE clause to the WhereClause. func (w *WhereClause) Where(clause, passedParam string, allowedValues ...string) *WhereClause { if passedParam == "" { return w } if len(allowedValues) != 0 && !contains(allowedValues, passedParam) { return w } w.addWhere() w.Clause += clause w.Params = append(w.Params, passedParam) return w } func (w *WhereClause) addWhere() { // if string is empty add "WHERE", else add AND if w.Clause == "" { w.Clause += "WHERE " } else { if w.useOr { w.Clause += " OR " return } w.Clause += " AND " } } // Or enables using OR instead of AND func (w *WhereClause) Or() *WhereClause { w.useOr = true return w } // And enables using AND instead of OR func (w *WhereClause) And() *WhereClause { w.useOr = false return w } // In generates an IN clause. // initial is the initial part, e.g. "users.id". // Fields are the possible values. // Sample output: users.id IN ('1', '2', '3') func (w *WhereClause) In(initial string, fields ...[]byte) *WhereClause { if len(fields) == 0 { return w } w.addWhere() w.Clause += initial + " IN (" + generateQuestionMarks(len(fields)) + ")" fieldsInterfaced := make([]interface{}, len(fields)) for k, f := range fields { fieldsInterfaced[k] = string(f) } w.Params = append(w.Params, fieldsInterfaced...) return w } func generateQuestionMarks(x int) (qm string) { for i := 0; i < x-1; i++ { qm += "?, " } if x > 0 { qm += "?" } return qm } // ClauseSafe returns the clause, always containing something. If w.Clause is // empty, it returns "WHERE 1". func (w *WhereClause) ClauseSafe() string { if w.Clause == "" { return "WHERE 1" } return w.Clause } // Where is the same as WhereClause.Where, but creates a new WhereClause. func Where(clause, passedParam string, allowedValues ...string) *WhereClause { w := new(WhereClause) return w.Where(clause, passedParam, allowedValues...) }