Simple Twitter API Auth

twitter_auth.go

package twitter

import (
	"github.com/BurntSushi/toml"
	"os"
	"fmt"
	"sync"
	"bufio"
	"net/http"
	"io/ioutil"
	"encoding/base64"
	"encoding/json"
	"strings"
)

const BASE = "https://api.twitter.com"
const STREAM = "https://stream.twitter.com/1.1"

var setBearerTokenOnce sync.Once
var bearerToken string

type BearerTokenData struct {
	Token string `json:"access_token"`
	Type  string `json:"token_type"` 
}

type Client struct {
	ConsumerKey    string `toml:consumerKey`
	ConsumerSecret string `toml:consumerSecret`
	AccessToken    string `toml:accessToken`
	AccessSecret   string `toml:accessSecret`
	Http           *http.Client
}

func setBearerToken(c* Client) {
	unencodedCreds := fmt.Sprintf("%s:%s", c.ConsumerKey, c.ConsumerSecret)
	encodedCreds := base64.StdEncoding.EncodeToString([]byte(unencodedCreds))
	requestBody := strings.NewReader("grant_type=client_credentials")

	req, _ := http.NewRequest("POST", fmt.Sprintf("%s/oauth2/token", BASE), requestBody)
	req.Header.Add("Authorization", fmt.Sprintf("Basic %s", encodedCreds))
	req.Header.Add("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8")

	resp, _ := c.Http.Do(req)
	body, _ := ioutil.ReadAll(resp.Body)

	tokenData := BearerTokenData{}

	err := json.Unmarshal(body, &tokenData)
	if err != nil {
		fmt.Println("Error unmarshaling access token response")
	}
	fmt.Println(tokenData.Token)

	bearerToken = fmt.Sprintf("Bearer %s", tokenData.Token)
}

func NewClient() *Client {
	var client Client
	path := fmt.Sprintf("%s/config/twitter.toml", os.Getenv("GOPATH"))
	if _, err := toml.DecodeFile(path, &client); err != nil {
		panic(err.Error())
	}
	client.Http = &http.Client{}
	setBearerTokenOnce.Do(func() {setBearerToken(&client)})

	return &client
}