From 4d59a554970de40dabfb4e2d4dca023810529a15 Mon Sep 17 00:00:00 2001
From: Jan Semmelink <jan@uafrica.com>
Date: Thu, 4 Nov 2021 07:56:36 +0200
Subject: [PATCH] More reflection utilities
---
reflection/get.go | 69 +++++++++++++++++
reflection/reflection.go | 2 +-
reflection/type_clone.go | 68 +++++++++++++++++
reflection/type_clone_test.go | 134 ++++++++++++++++++++++++++++++++++
4 files changed, 272 insertions(+), 1 deletion(-)
create mode 100644 reflection/get.go
create mode 100644 reflection/type_clone.go
create mode 100644 reflection/type_clone_test.go
diff --git a/reflection/get.go b/reflection/get.go
new file mode 100644
index 0000000..99349f1
--- /dev/null
+++ b/reflection/get.go
@@ -0,0 +1,69 @@
+package reflection
+
+import (
+ "fmt"
+ "reflect"
+ "strings"
+
+ "gitlab.com/uafrica/go-utils/errors"
+)
+
+func Get(v reflect.Value, key string) (reflect.Value, error) {
+ return get("", v, key)
+}
+
+func get(name string, v reflect.Value, key string) (reflect.Value, error) {
+ if key == "" {
+ return v, nil
+ }
+
+ switch v.Kind() {
+ case reflect.Ptr:
+ return get(name, v.Elem(), key)
+
+ case reflect.Struct:
+ if key[0] != '.' {
+ return v, errors.Errorf("get(%s): key=\"%s\" does not start with '.'", name, key)
+ }
+ fieldName := key[1:]
+ remainingKey := ""
+ index := strings.IndexAny(fieldName, ".[")
+ if index > 0 {
+ fieldName = key[1 : index+1]
+ remainingKey = key[index+1:]
+ }
+ t := v.Type()
+ fieldIndex := 0
+ for fieldIndex = 0; fieldIndex < t.NumField(); fieldIndex++ {
+ if strings.SplitN(t.Field(fieldIndex).Tag.Get("json"), ",", 2)[0] == fieldName {
+ break
+ }
+ }
+ if fieldIndex >= t.NumField() {
+ return v, errors.Errorf("%s does not have field %s", name, fieldName)
+ }
+ return get(name+"."+fieldName, v.Field(fieldIndex), remainingKey)
+
+ case reflect.Slice:
+ if !strings.HasPrefix(key, "[]") {
+ return v, errors.Errorf("canot get %s from slice, expecting \"[]\" in the key", key)
+ }
+
+ //make array of results from each item in the slice
+ var result reflect.Value
+ for i := 0; i < v.Len(); i++ {
+ if vv, err := get(fmt.Sprintf("%s[%d]", name, i), v.Index(i), key[2:]); err != nil {
+ return v, errors.Wrapf(err, "failed on %s[%d]", name, i)
+ } else {
+ if !result.IsValid() {
+ result = reflect.MakeSlice(reflect.SliceOf(vv.Type()), 0, v.Len())
+ }
+ result = reflect.Append(result, vv)
+ }
+ }
+ return result, nil
+
+ default:
+ }
+ return v, errors.Errorf("Cannot get %s from %s", key, v.Kind())
+}
diff --git a/reflection/reflection.go b/reflection/reflection.go
index 14faf28..b5ddd25 100644
--- a/reflection/reflection.go
+++ b/reflection/reflection.go
@@ -52,7 +52,7 @@ func SetString(field reflect.Value, value string) {
return // Field doesn't exist
}
if field.Kind() != reflect.String {
- logger.Error("Claims: Field is not of type String: %v", field.Kind())
+ logger.Errorf("Claims: Field is not of type String: %v", field.Kind())
return
}
field.SetString(value)
diff --git a/reflection/type_clone.go b/reflection/type_clone.go
new file mode 100644
index 0000000..9cc2d1c
--- /dev/null
+++ b/reflection/type_clone.go
@@ -0,0 +1,68 @@
+package reflection
+
+import (
+ "reflect"
+ "strings"
+
+ "gitlab.com/uafrica/go-utils/errors"
+)
+
+func CloneType(t reflect.Type, replace map[string]reflect.Type) (reflect.Type, error) {
+ return clone("", t, replace)
+}
+
+func clone(name string, t reflect.Type, replace map[string]reflect.Type) (reflect.Type, error) {
+ switch t.Kind() {
+ case reflect.Struct:
+ fields := []reflect.StructField{}
+ for i := 0; i < t.NumField(); i++ {
+ f := t.Field(i)
+ n := strings.SplitN(f.Tag.Get("json"), ",", 2)[0] //exclude ,omitempty...
+ if n == "" {
+ n = f.Name
+ }
+ fieldName := name + "." + n
+ for replaceName, replaceType := range replace {
+ if strings.HasPrefix(replaceName, fieldName) {
+ if replaceName == fieldName {
+ f.Type = replaceType
+ } else {
+ clonedType, err := clone(fieldName, f.Type, replace)
+ if err != nil {
+ return t, errors.Wrapf(err, "failed to clone %s", fieldName)
+ }
+ f.Type = clonedType
+ }
+ }
+ }
+ if newType, ok := replace[fieldName]; ok {
+ f.Type = newType
+ }
+ fields = append(fields, f)
+ }
+ return reflect.StructOf(fields), nil
+
+ case reflect.Slice:
+ for replaceName, replaceType := range replace {
+ if strings.HasPrefix(replaceName, name+"[]") {
+ if replaceName == name+"[]" {
+ //full match
+ return replaceType, nil
+ } else {
+ elemType, err := clone(name+"[]", t.Elem(), replace)
+ if err != nil {
+ return t, errors.Wrapf(err, "failed to clone slice elem type")
+ }
+ return reflect.SliceOf(elemType), nil
+ }
+ } else {
+ return t, nil
+ }
+ }
+
+ return t, errors.Errorf("NYI")
+
+ default:
+ }
+ return t, errors.Errorf("cannot clone %v %s", t.Kind(), t.Name())
+}
diff --git a/reflection/type_clone_test.go b/reflection/type_clone_test.go
new file mode 100644
index 0000000..474bc09
--- /dev/null
+++ b/reflection/type_clone_test.go
@@ -0,0 +1,134 @@
+package reflection_test
+
+import (
+ "encoding/json"
+ "reflect"
+ "testing"
+
+ "gitlab.com/uafrica/go-utils/reflection"
+)
+
+func Test1(t *testing.T) {
+ doc := `
+ {
+ "took":872,
+ "timed_out":false,
+ "_shards":{
+ "total":38,
+ "successful":38,
+ "skipped":0,
+ "failed":0
+ },
+ "hits":{
+ "total":{
+ "value":10,
+ "relation":"eq"
+ },
+ "max_score":null,
+ "hits":[
+ {
+ "_index": "go-utils-audit-test-20211030",
+ "_type": "_doc",
+ "_id": "Tj9l5XwBWRiAneoYazic",
+ "_score": 1.2039728,
+ "_source": {
+ "@timestamp": "2021-10-30T15:03:20.000000+02:00",
+ "@end_time": "2021-10-30T15:03:21.000000+02:00",
+ "@duration_ms": 1000,
+ "test1": "6",
+ "test2": "ACC_00098",
+ "test3": 10,
+ "http": {
+ "method": "GET",
+ "path": "/accounts"
+ },
+ "http_method": "GET",
+ "http_path": "/accounts"
+ }
+ }
+ ]
+ }
+ }
+ `
+
+ //using default type, documents in _source:{} are parsed to map[string]interface{}
+ res := SearchResponseBody{}
+ if err := json.Unmarshal([]byte(doc), &res); err != nil {
+ t.Fatalf("cannot unmarshal response into default type: %+v", err)
+ }
+ for hitIndex, hit := range res.Hits.Hits {
+ t.Logf("doc[%d]: (%T)%+v", hitIndex, hit.Source, hit.Source)
+ }
+
+ //create type with own document type to use for _source field:
+ cloned, err := reflection.CloneType(
+ reflect.TypeOf(SearchResponseBody{}),
+ map[string]reflect.Type{
+ ".hits.hits[]._source": reflect.TypeOf(myDoc{}),
+ })
+ if err != nil {
+ t.Fatal(err)
+ }
+ t.Logf("cloned type: %v", cloned)
+
+ //unmarshal using new type to have correct type for each hit
+ resPtrValue := reflect.New(cloned)
+ if err := json.Unmarshal([]byte(doc), resPtrValue.Interface()); err != nil {
+ t.Fatalf("failed to decode into cloned type: %+v", err)
+ }
+ // clonedRes := resPtrValue.Interface()
+ // t.Logf("Coned res: %+v", clonedRes)
+
+ //get the replaced values as an array of docs
+ v, err := reflection.Get(resPtrValue, ".hits.hits[]._source")
+ if err != nil {
+ t.Fatalf("Did not get list: %+v", err)
+ }
+ docs, ok := v.Interface().([]myDoc)
+ if !ok {
+ t.Fatalf("%T is not []myDoc", v.Interface())
+ }
+ if len(docs) != 1 {
+ t.Fatalf("Got %d != 1", len(docs))
+ }
+ for _, doc := range docs {
+ t.Logf("doc: (%T)%+v", doc, doc)
+ }
+}
+
+type SearchResponseBody struct {
+ Took int `json:"took"` //milliseconds
+ TimedOut bool `json:"timed_out"`
+ Shards SearchResponseShards `json:"_shards"`
+ Hits SearchResponseHits `json:"hits"`
+}
+
+type SearchResponseShards struct {
+ Total int `json:"total"`
+ Successful int `json:"successful"`
+ Skipped int `json:"skipped"`
+ Failed int `json:"failed"`
+}
+
+type SearchResponseHits struct {
+ Total SearchResponseHitsTotal `json:"total"`
+ MaxScore *float64 `json:"max_score,omitempty"`
+ Hits []HitDoc `json:"hits"`
+}
+
+type SearchResponseHitsTotal struct {
+ Value int `json:"value"` //e.g. 0 when no docs matched
+ Relation string `json:"relation"` //e.g. "eq"
+}
+
+type HitDoc struct {
+ Index string `json:"_index"` //name of index
+ Type string `json:"_type"` //_doc
+ ID string `json:"_id"`
+ Score float64 `json:"_score"` //
+ Source map[string]interface{} `json:"_source"` //the document of itemType
+}
+
+type myDoc struct {
+ Test1 string `json:"test1"`
+}
--
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