// evalRecursive visit the given value recursively and push all of them to result
func (j *JSONPath) evalRecursive(input []reflect.Value, node *RecursiveNode) ([]reflect.Value, error) {
result := []reflect.Value{}
for _, value := range input {
results := []reflect.Value{}
value, isNil := template.Indirect(value)
if isNil {
continue
}
kind := value.Kind()
if kind == reflect.Struct {
for i := 0; i < value.NumField(); i++ {
results = append(results, value.Field(i))
}
} else if kind == reflect.Map {
for _, key := range value.MapKeys() {
results = append(results, value.MapIndex(key))
}
} else if kind == reflect.Array || kind == reflect.Slice || kind == reflect.String {
for i := 0; i < value.Len(); i++ {
results = append(results, value.Index(i))
}
}
if len(results) != 0 {
result = append(result, value)
output, err := j.evalRecursive(results, node)
if err != nil {
return result, err
}
result = append(result, output...)
}
}
return result, nil
}
// evalWildcard extract all contents of the given value
func (j *JSONPath) evalWildcard(input []reflect.Value, node *WildcardNode) ([]reflect.Value, error) {
results := []reflect.Value{}
for _, value := range input {
value, isNil := template.Indirect(value)
if isNil {
continue
}
kind := value.Kind()
if kind == reflect.Struct {
for i := 0; i < value.NumField(); i++ {
results = append(results, value.Field(i))
}
} else if kind == reflect.Map {
for _, key := range value.MapKeys() {
results = append(results, value.MapIndex(key))
}
} else if kind == reflect.Array || kind == reflect.Slice || kind == reflect.String {
for i := 0; i < value.Len(); i++ {
results = append(results, value.Index(i))
}
}
}
return results, nil
}
// evalField evaluates filed of struct or key of map.
func (j *JSONPath) evalField(input []reflect.Value, node *FieldNode) ([]reflect.Value, error) {
results := []reflect.Value{}
// If there's no input, there's no output
if len(input) == 0 {
return results, nil
}
for _, value := range input {
var result reflect.Value
value, isNil := template.Indirect(value)
if isNil {
continue
}
if value.Kind() == reflect.Struct {
var err error
if result, err = j.findFieldInValue(&value, node); err != nil {
return nil, err
}
} else if value.Kind() == reflect.Map {
result = value.MapIndex(reflect.ValueOf(node.Value))
}
if result.IsValid() {
results = append(results, result)
}
}
if len(results) == 0 {
return results, fmt.Errorf("%s is not found", node.Value)
}
return results, nil
}
// evalArray evaluates ArrayNode
func (j *JSONPath) evalArray(input []reflect.Value, node *ArrayNode) ([]reflect.Value, error) {
result := []reflect.Value{}
for _, value := range input {
value, isNil := template.Indirect(value)
if isNil || (value.Kind() != reflect.Array && value.Kind() != reflect.Slice) {
return input, fmt.Errorf("%v is not array or slice", value.Type())
}
params := node.Params
if !params[0].Known {
params[0].Value = 0
}
if params[0].Value < 0 {
params[0].Value += value.Len()
}
if !params[1].Known {
params[1].Value = value.Len()
}
if params[1].Value < 0 {
params[1].Value += value.Len()
}
if !params[2].Known {
value = value.Slice(params[0].Value, params[1].Value)
} else {
value = value.Slice3(params[0].Value, params[1].Value, params[2].Value)
}
for i := 0; i < value.Len(); i++ {
result = append(result, value.Index(i))
}
}
return result, nil
}
// evalArray evaluates ArrayNode
func (j *JSONPath) evalArray(input []reflect.Value, node *ArrayNode) ([]reflect.Value, error) {
result := []reflect.Value{}
for _, value := range input {
value, isNil := template.Indirect(value)
if isNil {
continue
}
if value.Kind() != reflect.Array && value.Kind() != reflect.Slice {
return input, fmt.Errorf("%v is not array or slice", value.Type())
}
params := node.Params
if !params[0].Known {
params[0].Value = 0
}
if params[0].Value < 0 {
params[0].Value += value.Len()
}
if !params[1].Known {
params[1].Value = value.Len()
}
if params[1].Value < 0 {
params[1].Value += value.Len()
}
sliceLength := value.Len()
if params[1].Value != params[0].Value { // if you're requesting zero elements, allow it through.
if params[0].Value >= sliceLength {
return input, fmt.Errorf("array index out of bounds: index %d, length %d", params[0].Value, sliceLength)
}
if params[1].Value > sliceLength {
return input, fmt.Errorf("array index out of bounds: index %d, length %d", params[1].Value-1, sliceLength)
}
}
if !params[2].Known {
value = value.Slice(params[0].Value, params[1].Value)
} else {
value = value.Slice3(params[0].Value, params[1].Value, params[2].Value)
}
for i := 0; i < value.Len(); i++ {
result = append(result, value.Index(i))
}
}
return result, nil
}
// evalField evaluates field of struct or key of map.
func (j *JSONPath) evalField(input []reflect.Value, node *FieldNode) ([]reflect.Value, error) {
results := []reflect.Value{}
// If there's no input, there's no output
if len(input) == 0 {
return results, nil
}
for _, value := range input {
var result reflect.Value
value, isNil := template.Indirect(value)
if isNil {
continue
}
if value.Kind() == reflect.Struct {
var err error
if result, err = j.findFieldInValue(&value, node); err != nil {
return nil, err
}
} else if value.Kind() == reflect.Map {
mapKeyType := value.Type().Key()
nodeValue := reflect.ValueOf(node.Value)
// node value type must be convertible to map key type
if !nodeValue.Type().ConvertibleTo(mapKeyType) {
return results, fmt.Errorf("%s is not convertible to %s", nodeValue, mapKeyType)
}
result = value.MapIndex(nodeValue.Convert(mapKeyType))
}
if result.IsValid() {
results = append(results, result)
}
}
if len(results) == 0 {
if j.allowMissingKeys {
return results, nil
}
return results, fmt.Errorf("%s is not found", node.Value)
}
return results, nil
}
// evalFilter filter array according to FilterNode
func (j *JSONPath) evalFilter(input []reflect.Value, node *FilterNode) ([]reflect.Value, error) {
results := []reflect.Value{}
for _, value := range input {
value, _ = template.Indirect(value)
if value.Kind() != reflect.Array && value.Kind() != reflect.Slice {
return input, fmt.Errorf("%v is not array or slice and cannot be filtered", value)
}
for i := 0; i < value.Len(); i++ {
temp := []reflect.Value{value.Index(i)}
lefts, err := j.evalList(temp, node.Left)
//case exists
if node.Operator == "exists" {
if len(lefts) > 0 {
results = append(results, value.Index(i))
}
continue
}
if err != nil {
return input, err
}
var left, right interface{}
if len(lefts) != 1 {
return input, fmt.Errorf("can only compare one element at a time")
}
left = lefts[0].Interface()
rights, err := j.evalList(temp, node.Right)
if err != nil {
return input, err
}
if len(rights) != 1 {
return input, fmt.Errorf("can only compare one element at a time")
}
right = rights[0].Interface()
pass := false
switch node.Operator {
case "<":
pass, err = template.Less(left, right)
case ">":
pass, err = template.Greater(left, right)
case "==":
pass, err = template.Equal(left, right)
case "!=":
pass, err = template.NotEqual(left, right)
case "<=":
pass, err = template.LessEqual(left, right)
case ">=":
pass, err = template.GreaterEqual(left, right)
default:
return results, fmt.Errorf("unrecognized filter operator %s", node.Operator)
}
if err != nil {
return results, err
}
if pass {
results = append(results, value.Index(i))
}
}
}
return results, nil
}