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https://github.com/liangyaopei/structmap

Golang converts a struct to map, including customizing key name, flatterning the sturct and customizing field's independent method.
https://github.com/liangyaopei/structmap

golang map marshal reflect struct

Last synced: about 1 month ago
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Golang converts a struct to map, including customizing key name, flatterning the sturct and customizing field's independent method.

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[中文版说明](README_zh.md)

This repo provides a function convert a struct in Golang to a map(unmarshal a struct to a map).It supports
1. use tag to define the name of a filed in struct when converted in map. If no tag is specified, it will the name of field as key.
2. a filed in struct can customize its to map method.
To note that the customized method should have `(string,interface{})` as output, with the `string` as key in map and `interface{}` as value in map.

Also, it skips unexported filed , nil pointer and field without tag.

## Tags
For now, it supports 4 tags:
- '-' means ignoring this field
- 'omitempty' means ignoring this field when it is empty
- 'dive' means recursively traversing the struct, converting every filed in struct to be a key in map
- 'wildcard' applies for string value, it returns "%" +value +"%", which is conveniently for db wildcard query

## Example
For example,
```go
type User struct {
Name string `map:"name,omitempty"` // string
Github GithubPage `map:"github,dive,omitempty"` // struct dive
NoDive StructNoDive `map:"no_dive,omitempty"` // no dive struct
MyProfile Profile `map:"my_profile,omitempty"` // struct implements its own method
}

type GithubPage struct {
URL string `map:"url"`
Star int `map:"star"`
}

type StructNoDive struct {
NoDive int `map:"no_dive_int"`
}

type Profile struct {
Experience string `map:"experience"`
Date time.Time `map:"time"`
}

// its own toMap method
func (p Profile) StructToMap() (key string, value interface{}) {
return "time", p.Date.Format(timeLayout)
}
```
by using
```go
res, err := structmap.StructToMap(&user, tag, methodName)
```
can be converted to be
```go
map[string]interface{}{
"name": "user",
"no_dive": map[string]int{"no_dive_int": 1},
// dive struct field
"url": "https://github.com/liangyaopei",
"star": 1,
// customized method
"time": "2020-07-21 12:00:00",
}
```

## Performance
Compared with using `marshal`/`unmarshal` function in `json` package, this repo has better performance.
```go
func BenchmarkStructToMapByJson(b *testing.B) {
user := newBenchmarkUser()
b.ResetTimer()
for i := 0; i < b.N; i++ {
data, _ := json.Marshal(&user)
m := make(map[string]interface{})
json.Unmarshal(data, &m)
}
}

func BenchmarkStructToMapByToMap(b *testing.B) {
user := newBenchmarkUser()
tag := "json"
methodName := ""
b.ResetTimer()
for i := 0; i < b.N; i++ {
struct_to_map.StructToMap(&user, tag, methodName)
}
}
```
The result of using `StructToMap`
```sh
$ go test ./... -bench=BenchmarkStructToMapByToMap -benchmem -run=^$ -count=10

BenchmarkStructToMapByToMap-4 1322222 960 ns/op 488 B/op 14 allocs/op
BenchmarkStructToMapByToMap-4 1225311 965 ns/op 488 B/op 14 allocs/op
BenchmarkStructToMapByToMap-4 1201177 947 ns/op 488 B/op 14 allocs/op
BenchmarkStructToMapByToMap-4 1308039 895 ns/op 488 B/op 14 allocs/op
BenchmarkStructToMapByToMap-4 1201592 936 ns/op 488 B/op 14 allocs/op
BenchmarkStructToMapByToMap-4 1351603 882 ns/op 488 B/op 14 allocs/op
BenchmarkStructToMapByToMap-4 1361508 878 ns/op 488 B/op 14 allocs/op
BenchmarkStructToMapByToMap-4 1355869 876 ns/op 488 B/op 14 allocs/op
BenchmarkStructToMapByToMap-4 1353205 1151 ns/op 488 B/op 14 allocs/op
BenchmarkStructToMapByToMap-4 1278057 1487 ns/op 488 B/op 14 allocs/op
```
The result of using `json` package
```sh
$ go test ./... -bench=BenchmarkStructToMapByJson -benchmem -run=^$ -count=10
BenchmarkStructToMapByJson-4 383409 3171 ns/op 992 B/op 30 allocs/op
BenchmarkStructToMapByJson-4 314690 3297 ns/op 992 B/op 30 allocs/op
BenchmarkStructToMapByJson-4 363764 3009 ns/op 992 B/op 30 allocs/op
BenchmarkStructToMapByJson-4 365799 3122 ns/op 992 B/op 30 allocs/op
BenchmarkStructToMapByJson-4 361111 3057 ns/op 992 B/op 30 allocs/op
BenchmarkStructToMapByJson-4 335830 3176 ns/op 992 B/op 30 allocs/op
BenchmarkStructToMapByJson-4 347206 3069 ns/op 992 B/op 30 allocs/op
BenchmarkStructToMapByJson-4 380973 3067 ns/op 992 B/op 30 allocs/op
BenchmarkStructToMapByJson-4 373834 3000 ns/op 992 B/op 30 allocs/op
BenchmarkStructToMapByJson-4 373597 3206 ns/op 992 B/op 30 allocs/op
```