libhosty

Description

libhosty is a pure golang library to manipulate hosts-like files. It is inspired by txeh, with some enrichments.

Table of Contents

• Description
• Table of Contents
• Main Features
• Requirements
• Installation
• Usage
• Contributing
  • Templates
• Credits
• License

Main Features

• Comment/Uncomment a line without removing it from the file
• Restore the default hosts file for your system
• Add/Remove Address lines
• Add/Remove Comment lines
• Add/Remove Empty lines
• Query by hostname
• Automatically handles duplicate entries

Requirements

Requires go >= 1.21

Installation

Ensure you have go on your system

> go version
go version go1.22.5 linux/amd64

and pull the library

> go get github.com/areYouLazy/libhosty

Usage

To use the library, just import it and call the Init() method.

To load a custom hosts file use the InitFromCustomPath(path string) routine

To parse an inline hosts file use the InitFromString(lines string) routine

Note: This code doesn't handle errors for readability purposes, but you SHOULD!

package main

import "github.com/areYouLazy/libhosty"

func main() {
    //you can initialize libhosty with a custom path
    //
    // cnf, _ := libhosty.InitFromCustomPath("/path/to/my/custom/hosts/file")
    
    // or you can parse an inline hosts file
    //
    // hfile := `# Example of an inline hosts file
    // 127.0.0.1  localhost
    // ::1        localhost
    // 1.1.1.1    cloudflare.dns
    // 8.8.8.8    google.dns`
    // cnf, _ := libhosty.InitFromString(hfile)
    
    // load hosts file from default OS location
    hfl, _ := libhosty.Init()
    
    //add an empty line
    hfl.AddEmptyFileLine()
    
    //add a host with a comment
    hfl.AddHostFileLine("12.12.12.12", "my.host.name", "comment on my hostname!")
    
    //add a comment
    hfl.AddCommentFileLine("just a comment")
    
    //add an empty line
    hfl.AddEmptyFileLine()
    
    //add another host without comment
    hfl.AddHostsFileLine("13.13.13.13", "another.host.name", "")
    
    //add another fqdn to the previous ip
    hfl.AddHostsFileLine("12.12.12.12", "second.host.name", "")
    
    // comment for host lines can be done by hostname, row line
    // or IP (as net.IP or string)
    //
    // Comment the line with address 12.12.12.12
    //
    // By-Row-Number
    hfl.CommentHostsFileLineByRow(idx)
    //
    // By-Hostname
    hfl.CommentHostsFileLinesByHostname("second.host.name")
    //
    // By-Address-As-IP
    ip := net.ParseIP("12.12.12.12")
    hfl.CommentHostsFileLinesByIP(ip)
    //
    // By-Address-As-String
    hfl.CommentHostsFileLinesByAddress("12.12.12.12")
    
    // render the hosts file
    fmt.Println(hfl.RenderHostsFile())
    
    // write file to disk
    hfl.WriteHostsFile()
    
    // or to a custom location
    hfl.WriteHostsFileTo("/home/sonica/hosts-export.txt")
    
    // restore the original hosts file based on running OS
    hfl.RestoreTemplate()
    
    // render the hosts file
    fmt.Println(hfl.RenderHostsFile())
    
    // write to disk
    hfl.WriteHostsFile()
}

The 1st fmt.Println() should output something like this (in a linux host)

# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1               localhost.localdomain localhost
::1                     localhost6.localdomain6 localhost6

# 12.12.12.12           my.host.name second.host.name   #comment on my hostname!
# just a comment line

13.13.13.13             another.host.name

While the 2nd fmt.Println() should output the default template for your OS

# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1               localhost.localdomain localhost
::1                     localhost6.localdomain6 localhost6

If you handle errors properly, you'll notice that this example program will fail on the SaveHostsFile() call if started as a normal user, as editing the hosts file requires root privileges. This does not prevent libhosty from loading, managing, rendering and exporting the hosts file

Contributing

Issues and PRs are more than welcome!

Templates

If you find a hosts template (like the Docker one) that you think can be useful to have in this library feel free to open an Issue/Pull Request

Credits

Project Contributors will be listed here

License

Licenses under Apache License 2.0