New Criteria API

model/criteria/criteria.go

@@ -0,0 +1,71 @@
+// Package criteria implements a Criteria API based on Masterminds/squirrel
+package criteria
+
+import (
+	"encoding/json"
+
+	"github.com/Masterminds/squirrel"
+)
+
+type Expression = squirrel.Sqlizer
+
+type Criteria struct {
+	Expression
+	Sort   string
+	Order  string
+	Max    int
+	Offset int
+}
+
+func (c Criteria) ToSql() (sql string, args []interface{}, err error) {
+	return c.Expression.ToSql()
+}
+
+func (c Criteria) MarshalJSON() ([]byte, error) {
+	aux := struct {
+		All    []Expression `json:"all,omitempty"`
+		Any    []Expression `json:"any,omitempty"`
+		Sort   string       `json:"sort"`
+		Order  string       `json:"order,omitempty"`
+		Max    int          `json:"max,omitempty"`
+		Offset int          `json:"offset"`
+	}{
+		Sort:   c.Sort,
+		Order:  c.Order,
+		Max:    c.Max,
+		Offset: c.Offset,
+	}
+	switch rules := c.Expression.(type) {
+	case Any:
+		aux.Any = rules
+	case All:
+		aux.All = rules
+	default:
+		aux.All = All{rules}
+	}
+	return json.Marshal(aux)
+}
+
+func (c *Criteria) UnmarshalJSON(data []byte) error {
+	var aux struct {
+		All    unmarshalConjunctionType `json:"all,omitempty"`
+		Any    unmarshalConjunctionType `json:"any,omitempty"`
+		Sort   string                   `json:"sort"`
+		Order  string                   `json:"order,omitempty"`
+		Max    int                      `json:"max,omitempty"`
+		Offset int                      `json:"offset"`
+	}
+	if err := json.Unmarshal(data, &aux); err != nil {
+		return err
+	}
+	if len(aux.Any) > 0 {
+		c.Expression = Any(aux.Any)
+	} else if len(aux.All) > 0 {
+		c.Expression = All(aux.All)
+	}
+	c.Sort = aux.Sort
+	c.Order = aux.Order
+	c.Max = aux.Max
+	c.Offset = aux.Offset
+	return nil
+}