go-cli-prompt

go-cli-prompt

go-cli-prompt is a simple go library that can be used to display a prompt (or series of prompts) for user input and collect the result(s). It is highly configurable and provides a framework for supplying default values, validating input, serializing output, and cancellation via conetex.Context.

By default, I/O takes place on os.Stdin / os.Stdout; However any implementation of io.Reader / io.Writer may be supplied.

Getting Started

Installing

• go get github.com/bchivari/go-cli-prompt

Examples

Simple Prompt

• A simple example of how to display a single prompt
• See code...

Code

namePrompt := prompt.Prompt{
    PromptMessage: "Enter Name",
    AllowNil:      false,
}

// Blocks & re-prompts until valid input is received
name, err := namePrompt.Show()
if err != nil {
    fmt.Printf("Hello %v!", name.(string))
}

Output

Enter Name: Bob
Hello Bob!

Multi-Prompt

• See code...

Code

namePrompt := prompt.CliPrompt{
    PromptMessage: "Name",
    MapKey:        "name",
}

agePrompt := prompt.CliPrompt{
    PromptMessage: "Age",
    InputValidatorFunc: func(s string) bool {
        i, err := strconv.Atoi(s)
        if err != nil {
            return false
        }
        if i >= 0 && i <= 150 {
            return true
        }
        return false
    },
    InvalidInputMessage: "Age should be between 0 - 150",
    MapKey:              "age",
}

var (
    ret map[string]interface{}
    err error
)

ret, err = prompt.MakePromptChain(namePrompt, agePrompt).Show()
if err != nil {
    return
}

fmt.Printf("Got: %#v\n", ret)
fmt.Printf("Hello %v, you are %v years old!", ret["name"].(string), ret["age"].(string))

Output

Name: Bob
Age: 199

Age should be between 0 - 150 [199]

Age: 50
Got: map[string]interface {}{"age":"50", "name":"Bob"}
Hello Bob, you are 50 years old!

Simple Prompt With Regexp Validation

• See code...

Code

namePrompt := prompt.CliPrompt{
    PromptMessage: "Enter Name",
    InputValidatorRegex: regexp.MustCompile(`^[a-zA-Z]*$`),
    AllowNil: true,
}

// Try entering a number
name := namePrompt.Show()
if name != nil {
    fmt.Printf("Hello %v!", name.(string))
}

Output

Enter Name: 123

Invalid Input [123]

Enter Name: Bob
Hello Bob!

Prompt With Default Value and Custom Validation

• See code...

Code

ipPrompt := prompt.CliPrompt{
    PromptMessage:   "IP Address",
    DefaultAsString: "192.168.1.1",
    InputValidatorFunc: func(s string) bool {
        parsedIp := net.ParseIP(s)
        if parsedIp == nil {
            return false
        }
        return true
    },
    OutputSerializerFunc: func(s string) (interface{}, error) {
        parsedIp := net.ParseIP(s)
        if parsedIp == nil {
            return nil, fmt.Errorf("unparsable IP address") // This shouldn't happen if the validator is correct
        }
        return parsedIp, nil
    },
    InvalidInputMessage: "Not a valid IP address",
}

ret := ipPrompt.Show()

fmt.Printf("IP is %v!", ret.(net.IP))

Output 1

IP Address [192.168.1.1]: Not an IP

Not a valid IP address [Not an IP]

IP Address [192.168.1.1]: 10.0.0.1
IP is 10.0.0.1!

Output 2 - Using default

IP Address [192.168.1.1]: 
IP is 192.168.1.1!

More examples

• See code...

Full Documentation

Authors

Brad Chivari
@tracklessca

Version History

• 0.1
  • Initial Release

License

This project is licensed under Apace License, Version 2.0 - see the LICENSE file for details