Finish minimal feature set, start with tests

database/accessor/accessor-json-string.go

@@ -0,0 +1,101 @@
+package accessor
+
+import (
+	"fmt"
+
+	"github.com/tidwall/gjson"
+	"github.com/tidwall/sjson"
+)
+
+// JSONAccessor is a json string with get functions.
+type JSONAccessor struct {
+	json *string
+}
+
+// NewJSONAccessor adds the Accessor interface to a JSON string.
+func NewJSONAccessor(json *string) *JSONAccessor {
+	return &JSONAccessor{
+		json: json,
+	}
+}
+
+// Set sets the value identified by key.
+func (ja *JSONAccessor) Set(key string, value interface{}) error {
+	result := gjson.Get(*ja.json, key)
+	if result.Exists() {
+		switch value.(type) {
+		case string:
+			if result.Type != gjson.String {
+				return fmt.Errorf("tried to set field %s (%s) to a %T value", key, result.Type.String(), value)
+			}
+		case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64, float32, float64:
+			if result.Type != gjson.Number {
+				return fmt.Errorf("tried to set field %s (%s) to a %T value", key, result.Type.String(), value)
+			}
+		case bool:
+			if result.Type != gjson.True && result.Type != gjson.False {
+				return fmt.Errorf("tried to set field %s (%s) to a %T value", key, result.Type.String(), value)
+			}
+		}
+	}
+
+	new, err := sjson.Set(*ja.json, key, value)
+	if err != nil {
+		return err
+	}
+	*ja.json = new
+	return nil
+}
+
+// GetString returns the string found by the given json key and whether it could be successfully extracted.
+func (ja *JSONAccessor) GetString(key string) (value string, ok bool) {
+	result := gjson.Get(*ja.json, key)
+	if !result.Exists() || result.Type != gjson.String {
+		return emptyString, false
+	}
+	return result.String(), true
+}
+
+// GetInt returns the int found by the given json key and whether it could be successfully extracted.
+func (ja *JSONAccessor) GetInt(key string) (value int64, ok bool) {
+	result := gjson.Get(*ja.json, key)
+	if !result.Exists() || result.Type != gjson.Number {
+		return 0, false
+	}
+	return result.Int(), true
+}
+
+// GetFloat returns the float found by the given json key and whether it could be successfully extracted.
+func (ja *JSONAccessor) GetFloat(key string) (value float64, ok bool) {
+	result := gjson.Get(*ja.json, key)
+	if !result.Exists() || result.Type != gjson.Number {
+		return 0, false
+	}
+	return result.Float(), true
+}
+
+// GetBool returns the bool found by the given json key and whether it could be successfully extracted.
+func (ja *JSONAccessor) GetBool(key string) (value bool, ok bool) {
+	result := gjson.Get(*ja.json, key)
+	switch {
+	case !result.Exists():
+		return false, false
+	case result.Type == gjson.True:
+		return true, true
+	case result.Type == gjson.False:
+		return false, true
+	default:
+		return false, false
+	}
+}
+
+// Exists returns the whether the given key exists.
+func (ja *JSONAccessor) Exists(key string) bool {
+	result := gjson.Get(*ja.json, key)
+	return result.Exists()
+}
+
+// Type returns the accessor type as a string.
+func (ja *JSONAccessor) Type() string {
+	return "JSONAccessor"
+}