Reintroduce ConvertValue(interface{}) (#41)

* Reintroduce ConvertValue(interface{})

This PR re-introduces the ConvertValue(interface{}) method, but relocates it to
the definitions package.

* Updated ConvertValue

* Fix lint issues

Author: jeremyrickard

bundle/definition/schema.go

@@ -2,6 +2,8 @@ package definition
 
 import (
 	"encoding/json"
+	"strconv"
+	"strings"
 
 	"github.com/pkg/errors"
 	"github.com/qri-io/jsonschema"
@@ -107,3 +109,34 @@ func (s *Schema) UnmarshalJSON(data []byte) error {
 	}
 	return json.Unmarshal(data, &wrapper)
 }
+
+// ConvertValue attempts to convert the given string value to the type from the
+// definition. Note: this is only applicable to string, number, integer and boolean types
+func (s *Schema) ConvertValue(val string) (interface{}, error) {
+	dataType, ok, err := s.GetType()
+	if !ok {
+		return nil, errors.Wrapf(err, "unable to determine type: %v", s.Type)
+	}
+	switch dataType {
+	case "string":
+		return val, nil
+	case "number":
+		num, err := strconv.ParseFloat(val, 64)
+		if err != nil {
+			return nil, errors.Wrapf(err, "unable to convert %s to number", val)
+		}
+		return num, nil
+	case "integer":
+		return strconv.Atoi(val)
+	case "boolean":
+		if strings.ToLower(val) == "true" {
+			return true, nil
+		} else if strings.ToLower(val) == "false" {
+			return false, nil
+		} else {
+			return false, errors.Errorf("%q is not a valid boolean", val)
+		}
+	default:
+		return nil, errors.New("invalid definition")
+	}
+}

bundle/definition/schema_test.go

@@ -269,3 +269,69 @@ func valueTestJSON(kind, def, enum string) []byte {
 		"enum": [ %s ]
 	}`, kind, def, enum))
 }
+
+func TestConvertValue(t *testing.T) {
+	pd := Schema{
+		Type: "boolean",
+	}
+	is := assert.New(t)
+
+	out, _ := pd.ConvertValue("true")
+	is.True(out.(bool))
+	out, _ = pd.ConvertValue("false")
+	is.False(out.(bool))
+	out, _ = pd.ConvertValue("barbeque")
+	is.False(out.(bool))
+
+	pd.Type = "string"
+	out, err := pd.ConvertValue("hello")
+	is.NoError(err)
+	is.Equal("hello", out.(string))
+
+	pd.Type = "integer"
+	out, err = pd.ConvertValue("123")
+	is.NoError(err)
+	is.Equal(123, out.(int))
+
+	_, err = pd.ConvertValue("onetwothree")
+	is.Error(err)
+
+	pd.Type = "number"
+	out, err = pd.ConvertValue("123")
+	is.NoError(err)
+	is.Equal(float64(123), out.(float64))
+
+	out, err = pd.ConvertValue("5.5")
+	is.NoError(err)
+	is.Equal(5.5, out.(float64))
+
+	_, err = pd.ConvertValue("nope")
+	is.Error(err)
+
+	pd.Type = "array"
+	_, err = pd.ConvertValue("nope")
+	is.Error(err)
+
+	_, err = pd.ConvertValue("123")
+	is.Error(err)
+
+	_, err = pd.ConvertValue("true")
+	is.Error(err)
+
+	_, err = pd.ConvertValue("123.5")
+	is.Error(err)
+
+	pd.Type = "object"
+	_, err = pd.ConvertValue("nope")
+	is.Error(err)
+
+	_, err = pd.ConvertValue("123")
+	is.Error(err)
+
+	_, err = pd.ConvertValue("true")
+	is.Error(err)
+
+	_, err = pd.ConvertValue("123.5")
+	is.Error(err)
+
+}