Golang(9)File Management

Golang(9)File Management

7.1 XML 
import (
     “encoding/xml”
     “fmt”
     “io/ioutil”
     “os"
)

xml.Unmarshal(data []byte, v inteface{}) error
xml.Marshal(v interface{}) ([]byte, error)
xml.MarshalIndent(v interface{}, prefix, indent string) ([]byte, error)

7.2 JSON Handling
JSON(Javascript Object Notation)

Here is the sample JSON string
{“servers”:[{“serverName”:”Shanghai_VPN”, “serverIP”:”127.0.0.1”},{“serverName”:”Beijing_VPN”,”serverIP”:”127.0.0.2"}]}

Parse JSON
func Unmarshal(data []byte, v interface{}) error

Here is the example how to use this function.
package main

import (
     "encoding/json"
     "fmt"
)

type Server struct {
     ServerName string
     ServerIP   string
}

type Serverslice struct {
     Servers []Server
}

func main() {
     var s Serverslice
     str := `{"servers":[{"serverName":"Shanghai_VPN","serverIP":"127.0.0.1"},{"serverName":"Beijing_VPN","serverIP":"127.0.0.2"}]}`
     json.Unmarshal([]byte(str), &s)
     fmt.Println(s)
     fmt.Println(s.Servers[0])
     fmt.Println(s.Servers[0].ServerIP)
}

Remember to capital the first property name.

bool <——>JSON booleans
float64 <———>JSON numbers
string <————>JSON strings
nil <————> JSON null

We can use bitly simplejson to parse the unknown format JSON string.
https://github.com/bitly/go-simplejson

>go get github.com/bitly/go-simplejson

package main

import (
     "fmt"
     "github.com/bitly/go-simplejson"
)

func main() {
     js, _ := simplejson.NewJson([]byte(`{
    "test": {
        "array": [1, 2, 3],
        "int": 10,
        "float": 5.150,
        "bignum": 9223372036854775807,
        "string": "simplejson",
        "bool": true
    }
    }`))

     arr, _ := js.Get("test").Get("array").Array()
     i, _ := js.Get("test").Get("int").Int()
     ms := js.Get("test").Get("string").MustString()

     fmt.Println(arr)
     fmt.Println(i)
     fmt.Println(ms)
}

The console output is as follow:
>go run src/com/sillycat/easygoapp/main.go 
[1 2 3] 10 simplejson

Generate JSON
func Marshal(v interface{}) ([]byte, error)

package main

import (
     "encoding/json"
     "fmt"
)

type Server struct {
     ServerName string
     ServerIP   string
}

type Serverslice struct {
     Servers []Server
}

func main() {
     var s Serverslice
     s.Servers = append(s.Servers, Server{ServerName: "Shanghai_VPN", ServerIP: "127.0.0.1"})
     s.Servers = append(s.Servers, Server{ServerName: "Beijing_VPN", ServerIP: "127.0.0.2"})
     b, err := json.Marshal(s)
     if err != nil {
          fmt.Println("json err:", err)
     }
     fmt.Println(string(b))
}

The console output should be as follow:
{"Servers":[{"ServerName":"Shanghai_VPN","ServerIP":"127.0.0.1"},{"ServerName":"Beijing_VPN","ServerIP":"127.0.0.2"}]}

7.3 Regex
https://github.com/astaxie/build-web-application-with-golang/blob/master/ebook/07.3.md

7.4 Template
https://github.com/astaxie/build-web-application-with-golang/blob/master/ebook/07.4.md

7.5 File Operation
https://github.com/astaxie/build-web-application-with-golang/blob/master/ebook/07.5.md

7.6 String Operation
https://github.com/astaxie/build-web-application-with-golang/blob/master/ebook/07.6.md



References:
https://github.com/astaxie/build-web-application-with-golang/blob/master/ebook/07.0.md