Resolves #32 - Add support for URL Encoded filters

.editorconfig

@@ -0,0 +1,7 @@
+; https://editorconfig.org/
+root = true
+; Primarily to fix the tab width of GitHub
+
+[{go.mod,go.sum,*.go,.gitmodules}]
+indent_style = tab
+indent_size = 4

external/epsearchast/v3/ast.go

@@ -4,6 +4,7 @@ package epsearchast_v3
 import (
 	"encoding/json"
 	"fmt"
+	"net/url"
 	"strings"
 )
 
@@ -21,8 +22,21 @@ func GetAst(jsonTxt string) (*AstNode, error) {
 	err := json.Unmarshal([]byte(jsonTxt), astNode)
 
 	if err != nil {
-		return nil, fmt.Errorf("could not parse filter:%w", err)
-	} else if err := astNode.checkValid(); err != nil {
+		// url decode jsonTxt
+		decoded, urlDecodingError := url.QueryUnescape(jsonTxt)
+
+		if urlDecodingError == nil {
+			urlDecodingError = json.Unmarshal([]byte(decoded), astNode)
+
+			if urlDecodingError != nil {
+				return nil, fmt.Errorf("could not parse filter:%w, error parsing decoded filter: %v", err, urlDecodingError)
+			}
+		} else {
+			return nil, fmt.Errorf("could not parse filter:%w, error decoding: %v", err, urlDecodingError)
+		}
+	}
+
+	if err := astNode.checkValid(); err != nil {
 		return nil, fmt.Errorf("error validating filter:%w", err)
 	} else {
 		return astNode, nil

external/epsearchast/v3/ast_test.go

@@ -2,6 +2,7 @@ package epsearchast_v3
 
 import (
 	"github.com/stretchr/testify/require"
+	"net/url"
 	"testing"
 )
 
@@ -283,3 +284,47 @@ func TestAndReturnsErrorWithAnInvalidChild(t *testing.T) {
 	require.ErrorContains(t, err, "unknown operator FOO")
 	require.Nil(t, astNode)
 }
+
+func TestValidObjectThatIsUrlEncodedReturnsAst(t *testing.T) {
+	// Fixture Setup
+	// language=JSON
+	jsonTxt := `
+{
+	"type": "EQ",
+	"args": [ "status",  "paid"]
+}
+`
+	// Execute SUT
+	astNode, err := GetAst(url.QueryEscape(jsonTxt))
+
+	// Verify
+	require.NoError(t, err)
+	require.NotNil(t, astNode)
+}
+
+func TestInValidObjectThatIsUrlEncodedReturnsError(t *testing.T) {
+	// Fixture Setup
+	jsonTxt := `
+{
+	"type": "EQ",
+	"args": [ "status",  "paid"]
+`
+	// Execute SUT
+	astNode, err := GetAst(url.QueryEscape(jsonTxt))
+
+	// Verify
+	require.Error(t, err)
+	require.ErrorContains(t, err, "unexpected end of JSON input")
+	require.Nil(t, astNode)
+}
+
+func TestInValidUrlEncodingReturnsError(t *testing.T) {
+	// Fixture Setup
+	// Execute SUT
+	astNode, err := GetAst("%4")
+
+	// Verify
+	require.Error(t, err)
+	require.ErrorContains(t, err, "invalid URL escape")
+	require.Nil(t, astNode)
+}