HTTP Headers for spf13/pflag

This package allows use of repeated CLI flags defining HTTP headers, like:

CLI usage

# Long format
mycommand --header "Accept: text/plain" --header "Authorization: bearer sometoken"

# Short format
mycommand -H "Accept: text/plain" -H "Authorization: bearer sometoken"

# Repeated headers are supported and combined
mycommand -H "X-Array-Header: value1" -H "X-Array-Header: value2"
# Will return a slice value with value1 and value2 for key  X-Array-Header

# Headers are canonicalized
mycommand -H "content-type: application/json"
# Will have key Content-Type

Code usage

Simple

package main

import (
	"fmt"

	"github.com/spf13/pflag"
	"github.com/fgm/pflagheaders"
)

func main() {
	// HeaderFlag provides a preconfigured default flag
	h := pflagheaders.HeaderFlag()
	pflag.Parse()

	fmt.Printf("Headers:\n%s\n", h)
	// The resulting http.Header is available after Parse:
	fmt.Printf("Inner header:\n%#v\n", h.Header)
}

In projects using spf13/cobra

// In cmd/root.go
package cmd

import (
	pfh "github.com/fgm/pflagheaders"
	"github.com/spf13/cobra" // and others
)

var header = &pfh.Header{}

var rootCmd = &cobra.Command{
	/* generated by Cobra */
	Run: func(_ *cobra.Command, _ []string) { fmt.Println(header) }
}

func init() {
	cobra.OnInitialize(initConfig) // Generated by Cobra
	// ...other lines generated by Cobra
	// You can use the provided constants, or use other values.
	rootCmd.Flags().VarP(header, pfh.NameLong, pfh.NameShort, pfh.Help)
}