# Golang Masker

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Golang Masker is a simple utility of creating a mask for sensitive information.

* [Getting Started](#Getting-Started)

# Getting Started

```
$ go get -u github.com/ggwhite/go-masker
```

## Demo

There are two ways to get a masker instance:
#### 1. Get a instance directly from go-masker package
``` golang
package main

import (
	masker "github.com/ggwhite/go-masker"
)

func main() {
	masker.Name("ggwhite")
	masker.ID("A123456789")
	masker.Mobile("0978978978")
}
```

#### 2. Get a instance via `masker.New()`
``` golang
package main

import (
	masker "github.com/ggwhite/go-masker"
)

func main() {
	m := masker.New()
	m.Name("ggwhite")
	m.ID("A123456789")
	m.Mobile("0978978978")
}
```

## Mask Types

|Type        |Const        |Tag        |Description                                                                                            |
|:----------:|:-----------:|:---------:|:------------------------------------------------------------------------------------------------------|
|Name        |MName        |name       |mask the second letter and the third letter                                                            |
|Password    |MPassword    |password   |always return `************`                                                                           |
|Address     |MAddress     |addr       |keep first 6 letters, mask the rest                                                                    |
|Email       |MEmail       |email      |keep domain and the first 3 letters                                                                    |
|Mobile      |MMobile      |mobile     |mask 3 digits from the 4'th digit                                                                      |
|Telephone   |MTelephone   |tel        |remove `(`, `)`, ` `, `-` chart, and mask last 4 digits of telephone number, format to `(??)????-????` |
|ID          |MID          |id         |mask last 4 digits of ID number                                                                        |
|CreditCard  |MCreditCard  |credit     |mask 6 digits from the 7'th digit                                                                      |
|Struct      |MStruct      |struct     |mask the struct                                                                                        |
|URL         |MURL         |url        |mask the password field if present, eg http://admin:mysecretpassword@localhost:1234/uri                |

## Mask the `String`

`String` method requires two parameters, a mask type CONST and a string:
``` golang
package main

import (
	masker "github.com/ggwhite/go-masker"
)

func main() {
	masker.String(masker.MName, "ggwhite")
	masker.String(masker.MID, "A123456789")
	masker.String(masker.MMobile, "0987987987")
}
```
Result:
```
g**hite
A12345****
0987***987
```

## Custom Mask
``` golang
package main

import (
	masker "github.com/ggwhite/go-masker"
)

func main() {
	masker.String(masker.MName, "ggwhite")
	masker.String(masker.MID, "A123456789")
	masker.SetMask("-")
	masker.String(masker.MMobile, "0987987987")
}
```
Result:
```
g**hite
A12345****
0987---987
```


## Mask the `Struct`

You can define your struct and add tag `mask` to let masker know what kind of the format to mask.

> Field must be **public** in the struct.

``` golang
package main

import (
	"log"
	masker "github.com/ggwhite/go-masker"
)

type Foo struct {
	Name   string `mask:"name"`
	Mobile string `mask:"mobile"`
}

func main() {
	foo := &Foo{
		Name:   "ggwhite",
		Mobile: "0987987987",
	}
	t, err := masker.Struct(foo)
	log.Println(t)
	log.Println(t.(*Foo))
	log.Println(err)
}
```

Result:
```
t = &{g**hite 0987***987} 
err = <nil>
```

### Struct contain struct

``` golang
package main

import (
	masker "github.com/ggwhite/go-masker"
)

type Foo struct {
	Name   string `mask:"name"`
	Mobile string `mask:"mobile"`
	Qoo    *Qoo   `mask:"struct"`
}

type Qoo struct {
	Name      string `mask:"name"`
	Telephone string `mask:"tel"`
}

func main() {
	foo := &Foo{
		Name:   "ggwhite",
		Mobile: "0987987987",
		Qoo: &Qoo{
			Name:      "gino",
			Telephone: "0287658765",
		},
	}
	t, err := masker.Struct(foo)
	log.Println(t)
	log.Println(t.(*Foo).Qoo)
	log.Println(err)
}
```

Result:
```
t = &{g**hite 0987***987 0xc00000a080}
t.Qoo = &{g**o (02)8765-****}
err = <nil>
```

### Struct contain string slice
``` golang
package main

import (
	masker "github.com/ggwhite/go-masker"
)

type Foo struct {
	Name   string `mask:"name"`
	Mobile string `mask:"mobile"`
	IDs    []string   `mask:"id"`
}

func main() {
	foo := &Foo{
		Name:   "ggwhite",
		Mobile: "0987987987",
		IDs: []string{
			"A123456789",
			"A987654321",
		},
	}
	t, err := masker.Struct(foo)
	log.Println(t)
	log.Println(err)
}
```

Result:
```
t = &{g**hite 0987***987 [A12345**** A98765****]}
err = <nil>
```