简介
flag库是标准库的增强版本,让你的命令行程序飞起来
演示
功能
兼容go标准库
package main
import (
"fmt"
"github.com/guonaihong/flag"
)
func main() {
op := flag.String("dir", "", "open dir")
flag.Parse()
fmt.Printf("op = %s\n", *op)
}
// 运行
// go run main.go -dir test.file
// 输出
// op = test.file数组类型选项
很方便写出curl -H选项效果
package main
import (
"fmt"
"github.com/guonaihong/flag"
)
func main() {
h := flag.StringSlice("H, header", []string{}, "http header")
flag.Parse()
fmt.Printf("%#v\n", *h)
}
// 运行
// go run main.go -H "appkey:123" -H "User-Agent: main" --header "Accept: */*"
// 输出
// []string{"appkey:123", "User-Agent: main", "Accept: */*"}多选项支持
package main
import (
"fmt"
"github.com/guonaihong/flag"
)
func main() {
long := flag.String("l, long", "", "short long option")
flag.Parse()
fmt.Printf("long = %s\n", *long)
}
// 运行
// go run main.go -l hello
// go run main.go -long hello
// 输出
// long = hellomatchvar
详情 #9 很多时候使用bool选项，都是命令行传递bool选项 代码里面设置一个默认值，如下。
var openNull bool
delimiter := byte('\n')
command.Opt("0, null", "end each output line with NUL, not newline").
Flags(flag.Posix).
Var(&openNull)
if openNull {
delimiter = byte(0)
}现在可以使用MatchVar函数简化类似代码，如果命令函数传递-0或者-null，delimiter的值为'\n'
package main
import (
"fmt"
"github.com/guonaihong/flag"
)
func main() {
delimiter := byte(0)
flag.Opt("0, null", "end each output line with NUL, not newline").
Flags(flag.Posix).
MatchVar(&delimiter, byte('\n'))
flag.Parse()
fmt.Printf("%d\n", delimiter)
}
// 运行
// go run main.go -0
// 输出
// 10posix风格
- 命令组合
package main
import (
"fmt"
"github.com/guonaihong/flag"
)
func main() {
showEnds := flag.Opt("E, show-end", "display $ at end of each line").
Flags(flag.PosixShort).NewBool(false)
showTabs := flag.Opt("T, show-tabs", "display TAB characters as ^I").
Flags(flag.PosixShort).NewBool(false)
flag.Parse()
fmt.Printf("showEnds:%t, showTabs:%t\n", *showEnds, *showTabs)
}
// 运行
// go run main.go -TE
// 输出
// showEnds:true, showTabs:true- 贪婪模式
package main
import (
"fmt"
"github.com/guonaihong/flag"
)
func main() {
var heads []string
flag.Opt("H, header", "Pass custom header LINE to server (H)").
Flags(flag.GreedyMode).Var(&heads)
flag.Parse()
fmt.Printf("%#v\n", heads)
}
// 运行
// go run main.go -H appkey:test hello:world love:you
// 输出
// []string{"appkey:test", "hello:world", "love:you"}- -vvv 或者-v -v -v
package main
import (
"fmt"
"github.com/guonaihong/flag"
)
func main() {
var bs []bool
flag.Opt("v", "test bool slice").Flags(flag.PosixShort).Var(&bs)
flag.Parse()
switch len(bs) {
case 0:
fmt.Printf("No verbose info\n")
case 1:
fmt.Printf("Some verbose info\n")
case 2:
fmt.Printf("Tons of verbose info\n")
default:
fmt.Printf("别闹了\n")
}
}
// 运行
// go run main.go -v
// 输出
// Some verbose info
// 运行
// go run main.go -vv
// 输出
// Tons of verbose info
// 运行
// go run main.go -vvv
// 输出
// 别闹了子母命令
如果要实现一个主命令包含3个子命令(http, websocket, tcp)，其中http子命令又包含5个命令行选项，可以使用如下用法
package main
import (
"fmt"
"github.com/guonaihong/flag"
"os"
)
type httpOption struct {
Header []string
Forms []string
FormString string
Url string
Data string
}
type wsOption struct {
Ac int
An int
}
type streamOption struct {
}
func main() {
parent := flag.NewParentCommand(os.Args[0])
parent.SubCommand("http", "Use the http subcommand", func() {
argv0 := os.Args[0]
argv := parent.Args()
command := flag.NewFlagSet(argv0, flag.ExitOnError)
ho := httpOption{}
command.Opt("H, header", "Pass custom header LINE to server (H)").Var(&ho.Header)
command.Opt("F, form", "Specify HTTP multipart POST data (H)").Var(&ho.Forms)
command.Opt("form-string", "Specify HTTP multipart POST data (H)").Var(&ho.Forms)
command.Opt("url", "Specify a URL to fetch").Var(&ho.Url)
command.Opt("d, data", "HTTP POST data").Var(&ho.Data)
command.Parse(argv)
})
parent.SubCommand("ws, websocket", "Use the websocket subcommand", func() {
argv := parent.Args()
command := flag.NewFlagSet(os.Args[0], flag.ExitOnError)
wo := wsOption{}
command.Opt("an", "Number of requests to perform").DefaultVar(&wo.An, 1)
command.Opt("ac", "Number of multiple requests to make").DefaultVar(&wo.Ac, 1)
command.Parse(argv)
fmt.Printf("option = %#v\n", wo)
})
parent.SubCommand("tcp, udp", "Use the tcp or udp subcommand", func() {
//conn.Main(os.Args[0], parent.Args())
})
parent.Parse(os.Args[1:])
}
// 运行帮助信息
// go run main.go -h
// 输出
// Usage of /tmp/go-build387723503/b001/exe/main:
// http Use the http subcommand
// tcp, udp Use the tcp or udp subcommand
// ws, websocket Use the websocket subcommand
// 运行websocket子命令帮助信息
// go run
// Usage of /tmp/go-build229109289/b001/exe/main:
// -ac int
// Number of multiple requests to make
// -an int
// Number of requests to perform
// 运行websocket子命令
// go run main.go websocket -ac 2 -an 2
// 输出
// option = main.wsOption{Ac:2, An:2}泛型接口函数
package main
import (
"fmt"
"github.com/guonaihong/flag"
_ "os"
)
type TestOption struct {
Int int
Int64 int64
Strings []string
Int64s []int64
Int2 int
}
func main() {
option := TestOption{}
// DefaultVar是带默认值的泛型函数
// Var是不带默认值的泛型函数
flag.Opt("i, int", "test int").DefaultVar(&option.Int, 0)
flag.Opt("i64, int64", "test int64").DefaultVar(&option.Int64, int64(0))
flag.Opt("s, strings", "test []string").DefaultVar(&option.Strings, []string{})
flag.Opt("i64s, int64s", "test []int64").DefaultVar(&option.Int64s, []int64{})
flag.Opt("i2", "test int2").Var(&option.Int2)
flag.Parse()
fmt.Printf("%#v\n", option)
}
// 运行
// go run main.go -i 3 -i64 64 -i64s 64 -i64s 1 -i64s 2 -i64s 3 -s a -s b -s c
// 输出
// main.TestOption{Int:3, Int64:64, Strings:[]string{"a", "b", "c"}, Int64s:[]int64{64, 1, 2, 3}, Int2:0}绑定结构体
package main
import (
"fmt"
"github.com/guonaihong/flag"
_ "os"
)
type TestOption struct {
Int int `opt:"i, int" usage:"test int"`
Int64 int64 `opt:"i64, int64" usage:"test int64"`
Strings []string `opt:"s, strings" usage:"test []string"`
Int64s []int64 `opt:"i64s, int64s" usage:"test []int64"`
Int2 int `opt:"i2" usage:"test int2"`
}
func main() {
option := TestOption{}
flag.ParseStruct(&option)
fmt.Printf("%#v\n", option)
}
// 运行
// go run main.go -i 3 -i64 64 -i64s 64 -i64s 1 -i64s 2 -i64s 3 -s a -s b -s c
// 输出
// main.TestOption{Int:3, Int64:64, Strings:[]string{"a", "b", "c"}, Int64s:[]int64{64, 1, 2, 3}, Int2:0}