Implement Marshal porting Rack's code and tests

marshal.go

@@ -0,0 +1,69 @@
+package qs
+
+import (
+	"fmt"
+	"net/url"
+)
+
+func Marshal(hash map[string]interface{}) (string, error) {
+	return buildNestedQuery(hash, "")
+}
+
+func buildNestedQuery(value interface{}, prefix string) (string, error) {
+	components := ""
+
+	switch vv := value.(type) {
+	case []interface{}:
+		for i, v := range vv {
+			component, err := buildNestedQuery(v, prefix+"[]")
+
+			if err != nil {
+				return "", err
+			}
+
+			components += component
+
+			if i < len(vv)-1 {
+				components += "&"
+			}
+		}
+
+	case map[string]interface{}:
+		length := len(vv)
+
+		for k, v := range vv {
+			childPrefix := ""
+
+			if prefix != "" {
+				childPrefix = prefix + "[" + url.QueryEscape(k) + "]"
+			} else {
+				childPrefix = url.QueryEscape(k)
+			}
+
+			component, err := buildNestedQuery(v, childPrefix)
+
+			if err != nil {
+				return "", err
+			}
+
+			components += component
+			length -= 1
+
+			if length > 0 {
+				components += "&"
+			}
+		}
+
+	case string:
+		if prefix == "" {
+			return "", fmt.Errorf("value must be a map[string]interface{}")
+		}
+
+		components += prefix + "=" + url.QueryEscape(vv)
+
+	default:
+		components += prefix
+	}
+
+	return components, nil
+}

marshal_test.go

@@ -0,0 +1,47 @@
+package qs
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMarshal(t *testing.T) {
+	testables := []map[string]interface{}{
+		map[string]interface{}{"foo": "bar"},
+		map[string]interface{}{"foo": "1", "bar": "2"},
+		map[string]interface{}{"my weird field": "q1!2\"'w$5&7/z8)?"},
+		map[string]interface{}{"foo": []interface{}{nil}},
+		map[string]interface{}{"foo": []interface{}{""}},
+		map[string]interface{}{"foo": []interface{}{"bar"}},
+		map[string]interface{}{"foo": nil, "bar": ""},
+		map[string]interface{}{"foo": "bar", "baz": ""},
+		map[string]interface{}{"foo": []interface{}{"1", "2"}},
+		map[string]interface{}{"foo": "bar", "baz": []interface{}{"1", "2", "3"}},
+		map[string]interface{}{"foo": []interface{}{"bar"}, "baz": []interface{}{"1", "2", "3"}},
+		map[string]interface{}{"foo": []interface{}{"1", "2"}},
+		map[string]interface{}{"foo": "bar", "baz": []interface{}{"1", "2", "3"}},
+		map[string]interface{}{"x": map[string]interface{}{"y": map[string]interface{}{"z": "1"}}},
+		map[string]interface{}{"x": map[string]interface{}{"y": map[string]interface{}{"z": []interface{}{"1"}}}},
+		map[string]interface{}{"x": map[string]interface{}{"y": map[string]interface{}{"z": []interface{}{"1", "2"}}}},
+		map[string]interface{}{"x": map[string]interface{}{"y": []interface{}{map[string]interface{}{"z": "1"}}}},
+		map[string]interface{}{"x": map[string]interface{}{"y": []interface{}{map[string]interface{}{"z": []interface{}{"1"}}}}},
+		map[string]interface{}{"x": map[string]interface{}{"y": []interface{}{map[string]interface{}{"z": "1", "w": "2"}}}},
+		map[string]interface{}{"x": map[string]interface{}{"y": []interface{}{map[string]interface{}{"v": map[string]interface{}{"w": "1"}}}}},
+		map[string]interface{}{"x": map[string]interface{}{"y": []interface{}{map[string]interface{}{"z": "1", "v": map[string]interface{}{"w": "2"}}}}},
+		map[string]interface{}{"x": map[string]interface{}{"y": []interface{}{map[string]interface{}{"z": "1"}, map[string]interface{}{"z": "2"}}}},
+		map[string]interface{}{"x": map[string]interface{}{"y": []interface{}{map[string]interface{}{"z": "1", "w": "a"}, map[string]interface{}{"z": "2", "w": "3"}}}},
+	}
+
+	for _, v := range testables {
+		querystring, err := Marshal(v)
+
+		if assert.NoError(t, err) {
+			hash, err := Unmarshal(querystring)
+
+			if assert.NoError(t, err) {
+				assert.Equal(t, hash, v)
+			}
+		}
+	}
+}