Allow much more freedom to query for different things in /api/v1/beatmaps

common/where.go

@@ -0,0 +1,33 @@
+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{}
+}
+
+// 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
+	}
+	// checks passed, if string is empty add "WHERE"
+	if w.Clause == "" {
+		w.Clause += "WHERE "
+	} else {
+		w.Clause += " AND "
+	}
+	w.Clause += clause
+	w.Params = append(w.Params, passedParam)
+	return w
+}
+
+// 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...)
+}