implement json.Marshaler and json.Unmarshaler for Float4, Float8

Author: KirillMironov

pgtype/float4.go

@@ -3,6 +3,7 @@ package pgtype
 import (
 	"database/sql/driver"
 	"encoding/binary"
+	"encoding/json"
 	"fmt"
 	"math"
 	"strconv"
@@ -65,6 +66,29 @@ func (f Float4) Value() (driver.Value, error) {
 	return float64(f.Float32), nil
 }
 
+func (f Float4) MarshalJSON() ([]byte, error) {
+	if !f.Valid {
+		return []byte("null"), nil
+	}
+	return json.Marshal(f.Float32)
+}
+
+func (f *Float4) UnmarshalJSON(b []byte) error {
+	var n *float32
+	err := json.Unmarshal(b, &n)
+	if err != nil {
+		return err
+	}
+
+	if n == nil {
+		*f = Float4{}
+	} else {
+		*f = Float4{Float32: *n, Valid: true}
+	}
+
+	return nil
+}
+
 type Float4Codec struct{}
 
 func (Float4Codec) FormatSupported(format int16) bool {

pgtype/float4_test.go

@@ -21,3 +21,44 @@ func TestFloat4Codec(t *testing.T) {
 		{nil, new(*float32), isExpectedEq((*float32)(nil))},
 	})
 }
+
+func TestFloat4MarshalJSON(t *testing.T) {
+	successfulTests := []struct {
+		source pgtype.Float4
+		result string
+	}{
+		{source: pgtype.Float4{Float32: 0}, result: "null"},
+		{source: pgtype.Float4{Float32: 1.23, Valid: true}, result: "1.23"},
+	}
+	for i, tt := range successfulTests {
+		r, err := tt.source.MarshalJSON()
+		if err != nil {
+			t.Errorf("%d: %v", i, err)
+		}
+
+		if string(r) != tt.result {
+			t.Errorf("%d: expected %v to convert to %v, but it was %v", i, tt.source, tt.result, string(r))
+		}
+	}
+}
+
+func TestFloat4UnmarshalJSON(t *testing.T) {
+	successfulTests := []struct {
+		source string
+		result pgtype.Float4
+	}{
+		{source: "null", result: pgtype.Float4{Float32: 0}},
+		{source: "1.23", result: pgtype.Float4{Float32: 1.23, Valid: true}},
+	}
+	for i, tt := range successfulTests {
+		var r pgtype.Float4
+		err := r.UnmarshalJSON([]byte(tt.source))
+		if err != nil {
+			t.Errorf("%d: %v", i, err)
+		}
+
+		if r != tt.result {
+			t.Errorf("%d: expected %v to convert to %v, but it was %v", i, tt.source, tt.result, r)
+		}
+	}
+}

pgtype/float8.go

@@ -74,6 +74,29 @@ func (f Float8) Value() (driver.Value, error) {
 	return f.Float64, nil
 }
 
+func (f Float8) MarshalJSON() ([]byte, error) {
+	if !f.Valid {
+		return []byte("null"), nil
+	}
+	return json.Marshal(f.Float64)
+}
+
+func (f *Float8) UnmarshalJSON(b []byte) error {
+	var n *float64
+	err := json.Unmarshal(b, &n)
+	if err != nil {
+		return err
+	}
+
+	if n == nil {
+		*f = Float8{}
+	} else {
+		*f = Float8{Float64: *n, Valid: true}
+	}
+
+	return nil
+}
+
 type Float8Codec struct{}
 
 func (Float8Codec) FormatSupported(format int16) bool {
@@ -109,13 +132,6 @@ func (Float8Codec) PlanEncode(m *Map, oid uint32, format int16, value any) Encod
 	return nil
 }
 
-func (f *Float8) MarshalJSON() ([]byte, error) {
-	if !f.Valid {
-		return []byte("null"), nil
-	}
-	return json.Marshal(f.Float64)
-}
-
 type encodePlanFloat8CodecBinaryFloat64 struct{}
 
 func (encodePlanFloat8CodecBinaryFloat64) Encode(value any, buf []byte) (newBuf []byte, err error) {

pgtype/float8_test.go

@@ -21,3 +21,44 @@ func TestFloat8Codec(t *testing.T) {
 		{nil, new(*float64), isExpectedEq((*float64)(nil))},
 	})
 }
+
+func TestFloat8MarshalJSON(t *testing.T) {
+	successfulTests := []struct {
+		source pgtype.Float8
+		result string
+	}{
+		{source: pgtype.Float8{Float64: 0}, result: "null"},
+		{source: pgtype.Float8{Float64: 1.23, Valid: true}, result: "1.23"},
+	}
+	for i, tt := range successfulTests {
+		r, err := tt.source.MarshalJSON()
+		if err != nil {
+			t.Errorf("%d: %v", i, err)
+		}
+
+		if string(r) != tt.result {
+			t.Errorf("%d: expected %v to convert to %v, but it was %v", i, tt.source, tt.result, string(r))
+		}
+	}
+}
+
+func TestFloat8UnmarshalJSON(t *testing.T) {
+	successfulTests := []struct {
+		source string
+		result pgtype.Float8
+	}{
+		{source: "null", result: pgtype.Float8{Float64: 0}},
+		{source: "1.23", result: pgtype.Float8{Float64: 1.23, Valid: true}},
+	}
+	for i, tt := range successfulTests {
+		var r pgtype.Float8
+		err := r.UnmarshalJSON([]byte(tt.source))
+		if err != nil {
+			t.Errorf("%d: %v", i, err)
+		}
+
+		if r != tt.result {
+			t.Errorf("%d: expected %v to convert to %v, but it was %v", i, tt.source, tt.result, r)
+		}
+	}
+}