Add a YAML to JSON converter as yaml-helper

Signed-off-by: Knut Ahlers <knut@ahlers.me>

yaml/tojson.go

@@ -0,0 +1,46 @@
+package yaml
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+
+	yaml "gopkg.in/yaml.v2"
+)
+
+// ToJSON takes an io.Reader containing YAML source and converts it into
+// a JSON representation of the YAML object.
+func ToJSON(in io.Reader) (io.Reader, error) {
+	var body interface{}
+
+	if err := yaml.NewDecoder(in).Decode(&body); err != nil {
+		return nil, fmt.Errorf("Unable to unmarshal YAML: %s", err)
+	}
+
+	body = convert(body)
+
+	var buf = new(bytes.Buffer)
+	if err := json.NewEncoder(buf).Encode(body); err != nil {
+		return nil, fmt.Errorf("Unable to marshal JSON: %s", err)
+	}
+
+	return buf, nil
+}
+
+// Source: https://stackoverflow.com/a/40737676/1741281
+func convert(i interface{}) interface{} {
+	switch x := i.(type) {
+	case map[interface{}]interface{}:
+		m2 := map[string]interface{}{}
+		for k, v := range x {
+			m2[k.(string)] = convert(v)
+		}
+		return m2
+	case []interface{}:
+		for i, v := range x {
+			x[i] = convert(v)
+		}
+	}
+	return i
+}

yaml/tojson_test.go

@@ -0,0 +1,32 @@
+package yaml
+
+import (
+	"io/ioutil"
+	"strings"
+	"testing"
+)
+
+func TestToJSON(t *testing.T) {
+	src := `Services:
+-   Orders:
+    -   ID: $save ID1
+        SupplierOrderCode: $SupplierOrderCode
+    -   ID: $save ID2
+        SupplierOrderCode: 111111
+`
+
+	expected := `{"Services":[{"Orders":[{"ID":"$save ID1","SupplierOrderCode":"$SupplierOrderCode"},{"ID":"$save ID2","SupplierOrderCode":111111}]}]}
+`
+
+	j, err := ToJSON(strings.NewReader(src))
+	if err != nil {
+		t.Fatalf("ToJSON failed: %s", err)
+	}
+
+	real, _ := ioutil.ReadAll(j)
+	realString := string(real)
+
+	if expected != realString {
+		t.Errorf("Expected JSON was not created:\nEXPE: %q\nREAL: %q", expected, realString)
+	}
+}