Add support for headers, method, body and json path with arrays

jsonpath/jsonpath.go

@@ -3,28 +3,69 @@ package jsonpath
 import (
 	"encoding/json"
 	"fmt"
+	"strconv"
 	"strings"
 )
 
-func Eval(path string, b []byte) string {
-	var object map[string]interface{}
+func Eval(path string, b []byte) (string, error) {
+	var object interface{}
 	err := json.Unmarshal(b, &object)
 	if err != nil {
-		return ""
+		// Try to unmarshall it into an array instead
+		return "", err
 	}
 	return walk(path, object)
 }
 
-func walk(path string, object map[string]interface{}) string {
+func walk(path string, object interface{}) (string, error) {
 	keys := strings.Split(path, ".")
-	targetKey := keys[0]
-	// if there's only one key and the target key is that key, then return its value
-	if len(keys) == 1 {
-		return fmt.Sprintf("%v", object[targetKey])
-	}
+	currentKey := keys[0]
 	// if there's more than one key, then walk deeper
-	if len(keys) > 0 {
-		return walk(strings.Replace(path, fmt.Sprintf("%s.", targetKey), "", 1), object[targetKey].(map[string]interface{}))
+	if len(keys) > 1 {
+		switch value := extractValue(currentKey, object).(type) {
+		case map[string]interface{}:
+			return walk(strings.Replace(path, fmt.Sprintf("%s.", currentKey), "", 1), value)
+		case interface{}:
+			return fmt.Sprintf("%v", value), nil
+		default:
+			return "", fmt.Errorf("couldn't walk through '%s' because type was '%T', but expected 'map[string]interface{}'", currentKey, value)
+		}
 	}
-	return ""
+	// if there's only one key and the target key is that key, then return its value
+	return fmt.Sprintf("%v", extractValue(currentKey, object)), nil
+}
+
+func extractValue(currentKey string, value interface{}) interface{} {
+	// Check if the current key ends with [#]
+	if strings.HasSuffix(currentKey, "]") && strings.Contains(currentKey, "[") {
+		tmp := strings.SplitN(currentKey, "[", 3)
+		arrayIndex, err := strconv.Atoi(strings.Replace(tmp[1], "]", "", 1))
+		if err != nil {
+			return value
+		}
+		currentKey := tmp[0]
+		// if currentKey contains only an index (i.e. [0] or 0)
+		if len(currentKey) == 0 {
+			array := value.([]interface{})
+			if len(array) > arrayIndex {
+				if len(tmp) > 2 {
+					// Nested array? Go deeper.
+					return extractValue(fmt.Sprintf("%s[%s", currentKey, tmp[2]), array[arrayIndex])
+				}
+				return array[arrayIndex]
+			}
+			return nil
+		}
+		// if currentKey contains both a key and an index (i.e. data[0])
+		array := value.(map[string]interface{})[currentKey].([]interface{})
+		if len(array) > arrayIndex {
+			if len(tmp) > 2 {
+				// Nested array? Go deeper.
+				return extractValue(fmt.Sprintf("[%s", tmp[2]), array[arrayIndex])
+			}
+			return array[arrayIndex]
+		}
+		return nil
+	}
+	return value.(map[string]interface{})[currentKey]
 }