Pocket API authentication demo

README.md

go run main.go -key ...

and go to http://localhost:4343/login

main.go

package main

import (
	"bytes"
	"encoding/json"
	"errors"
	"flag"
	"io/ioutil"
	"log"
	"net/http"
	"net/url"
)

var address *string
var key *string

func init() {
	address = flag.String("address", ":4343", "address to run the server at")
	key = flag.String("key", "", "application key for Pocket API access")
}

func main() {
	flag.Parse()

	if *key == "" {
		log.Fatal("key is required")
	}

	http.HandleFunc("/login", handleLogin)
	http.HandleFunc("/redirect", handleRedirect)

	if err := http.ListenAndServe(*address, nil); err != nil {
		log.Fatal(err)
	}
}

type codeParameters struct {
	ConsumerKey string `json:"consumer_key"`
	RedirectURI string `json:"redirect_uri"`
}

type codeResponse struct {
	Code string `json:"code"`
}

func handleLogin(w http.ResponseWriter, r *http.Request) {
	data, err := json.Marshal(codeParameters{ConsumerKey: *key, RedirectURI: "http://localhost" + *address + "/redirect"})
	if err != nil {
		log.Fatal(err)
	}

	log.Println("data:", string(data))

	d, err := request("https://getpocket.com/v3/oauth/request", data)
	if err != nil {
		log.Fatal(err)
	}

	response := &codeResponse{}
	err = json.Unmarshal(d, response)
	if err != nil {
		log.Fatal(err)
	}

	log.Println("code:", response.Code)

	url := "https://getpocket.com/auth/authorize?request_token=" + response.Code +
		"&redirect_uri=http://localhost" + *address + "/" +
		url.PathEscape("redirect?code="+response.Code)

	http.Redirect(w, r, url, http.StatusFound)
}

type authorizeParameters struct {
	ConsumerKey string `json:"consumer_key"`
	Code        string `json:"code"`
}

type authorizeResponse struct {
	AccessToken string `json:"access_token"`
	Username    string `json:"username"`
}

func handleRedirect(w http.ResponseWriter, r *http.Request) {
	code := r.URL.Query().Get("code")

	data, err := json.Marshal(authorizeParameters{ConsumerKey: *key, Code: code})
	if err != nil {
		log.Fatal(err)
	}

	d, err := request("https://getpocket.com/v3/oauth/authorize", data)
	if err != nil {
		log.Fatal(err)
	}

	response := &authorizeResponse{}
	err = json.Unmarshal(d, response)
	if err != nil {
		log.Fatal(err)
	}

	log.Println("access_token:", response.AccessToken)
	w.Write([]byte("Hello " + response.Username))
}

func request(url string, data []byte) ([]byte, error) {
	req, err := http.NewRequest(http.MethodPost, url, bytes.NewBuffer(data))
	req.Header.Set("Content-Type", "application/json; charset=UTF-8")
	req.Header.Set("X-Accept", "application/json")
	if err != nil {
		return nil, err
	}

	client := &http.Client{}
	res, err := client.Do(req)
	if err != nil {
		return nil, err
	}

	defer res.Body.Close()

	if res.StatusCode != http.StatusOK {
		return nil, errors.New("request to " + url + " failed with status " + res.Status)
	}

	d, err := ioutil.ReadAll(res.Body)
	if err != nil {
		return nil, err
	}

	return d, nil
}