Execute POST GET request in golang, create headers

request.go

package request

import (
	"bytes"
	"encoding/json"
	"go.uber.org/zap"
	"io/ioutil"
	"net/http"
	"strings"
)

// CreateHeaderList is delegated to initialize a list of headers.
// Every row of the matrix contains [key,value]
func CreateHeaderList(headers ...string) [][]string {
	var list [][]string
	lenght := len(headers)

	list = make([][]string, lenght/2)
	counter := 0
	for i := 0; i < lenght; i += 2 {
		tmp := make([]string, 2)
		key := headers[i]
		value := headers[i+1]
		tmp[0] = key
		tmp[1] = value
		zap.S().Debug("createHeaderList | ", i, ") Key: ", key, " Value: ", value)
		list[counter] = tmp
		counter++
	}
	zap.S().Debug("createHeaderList | LIST: ", list)
	return list
}

func SendRequest(url, method string, headers [][]string, jsonStr []byte) map[string]string {

	// Create a custom request
	var req *http.Request
	var err error
	// Used for decode the JSON response
	var result map[string]string

	switch method {
	case "GET":
		zap.S().Debug("sendRequest | Creating GET REQ")
		req, err = http.NewRequest("GET", url, nil)
	case "POST":
		zap.S().Debug("sendRequest | Creating GET POST")
		req, err = http.NewRequest("POST", url, bytes.NewBuffer(jsonStr))
	case "PUT":
		zap.S().Debug("sendRequest | Creating GET PUT")
		return nil
	default:
		zap.S().Debug("sendRequest | Unkown method -> ", method)
		return nil
	}
	if err != nil {
		zap.S().Error("AuthenticateRequest | Unable to create request! ", err)
		return nil
	}

	lenght := len(headers)
	for i := 0; i < lenght; i++ {
		zap.S().Debug("sendRequest | Adding header: ", headers[i], " Len: ", len(headers[i]))

		key := headers[i][0]
		value := headers[i][1]
		if strings.Compare(`Authorization`, key) == 0 {
			req.Header.Add(key, value)
		} else {
			req.Header.Set(key, value)
		}
		zap.S().Debug("sendRequest | Adding header: {", key, "|", value, "}")
	}
	zap.S().Debug("sendRequest | Executing request ...")
	client := &http.Client{}
	resp, err := client.Do(req)
	if err != nil {
		zap.S().Debug("Error on response.\n[ERRO] -", err)
		return nil
	}
	defer resp.Body.Close()
	zap.S().Debug("sendRequest | Request executed, reading response ...")
	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		zap.S().Error("sendRequest | Unable to read response! ", err)
		return nil
	}
	json.Unmarshal(body, &result)
	return result
}

/*
Usage

func PingUrl(token, url string) bool {
	url += `/all_dbs`
	headers := request.CreateHeaderList("Authorization", "Bearer "+token)
	fmt.Println(request.SendRequest(url, `GET`, headers, nil))
	return true
}

func RetrieveToken(apikey string) string {
	headers := request.CreateHeaderList(`Accept`, `application/json`, `Content-Type`, `application/x-www-form-urlencoded`)
	encoded := url.Values{}
	encoded.Set("grant_type", "urn:ibm:params:oauth:grant-type:apikey")
	encoded.Set("apikey", apikey)
	url := "https://iam.cloud.ibm.com/identity/token"
	token := request.SendRequest(url, `POST`, headers, []byte(encoded.Encode()))
	zap.S().Debug("Token retrieved -> ", token)
	return token[`access_token`]
}

*/