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path: root/client.go
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package acme

import (
	"encoding/json"
	"errors"
	"io/ioutil"
	"log"
	"net/http"
	"regexp"
	"strconv"
	"time"

	"github.com/mgutz/ansi"
)

type Links map[string]string

// Client ...
type Client struct {
	Directory
	nonce chan string
}

type nextStep struct {
	Link       Links
	Location   string
	RetryAfter time.Duration
}

func (c Client) replyNonce(r *http.Response) {
	if rn := r.Header.Get("Replay-Nonce"); rn != "" {
		log.Println(ansi.Color("NONCE", "blue"), rn)
		c.nonce <- rn
	}
}

// NewClient fetches directory and initializes nonce
func NewClient(directory string) (*Client, error) {
	c := &Client{nonce: make(chan string, 10)}
	resp, err := http.Get(directory)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	defer c.replyNonce(resp)
	err = json.NewDecoder(resp.Body).Decode(&c.Directory)
	if err != nil {
		return nil, err
	}
	return c, nil
}

var errNoNonces = errors.New("out of nonces")

// Nonce implements jose nonce provider
func (c Client) Nonce() (string, error) {
	select {
	case nonce := <-c.nonce:
		return nonce, nil
	default:
		return "", errNoNonces
	}
}

// Important header fields
//
// Replay-Nonce		each response, required for next request
// Link			links to next stage
// Retry-After		polling interval
// Location		next step
// Content-Location	cert

// Action		Request		Response
//
// Register		POST new-reg	201 -> reg
// Request challenges	POST new-authz	201 -> authz
// Answer challenges	POST challenge	200
// Poll for status	GET  authz	200
// Request issuance	POST new-cert	201 -> cert
// Check for new cert	GET  cert	200

// request is used for
// new-reg, new-authz, challenge, new-cert
func (c *Client) post(uri string, s Signer, v interface{}) (*http.Response, error) {
	body, err := json.Marshal(v)
	if err != nil {
		return nil, err
	}
	log.Println(ansi.Color("POST", "red+b"), uri, string(body))

	signed, err := s.Sign(body, c)
	if err != nil {
		return nil, err
	}

	resp, err := http.Post(uri, "application/json", signed)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	defer c.replyNonce(resp)
	log.Println(ansi.Color("STATUS", "yellow"), resp.Status)

	if resp.StatusCode >= http.StatusBadRequest {
		var p Problem
		err = json.NewDecoder(resp.Body).Decode(&p)
		if err != nil {
			return resp, err
		}
		if err, ok := urnErrors[p.Type]; ok {
			p.Err = err
		}
		return resp, p
	}

	// DEBUG
	body, err = ioutil.ReadAll(resp.Body)
	if err != nil {
		return resp, err
	}
	log.Println(ansi.Color("RESP", "red"), string(body))
	return resp, json.Unmarshal(body, v)
	//return json.NewDecoder(resp.Body).Decode(v)
}

var linksRe = regexp.MustCompile(`^<(.*)>;rel="(.*)"`)

func parseHeader(r *http.Response) nextStep {
	var ns nextStep

	if lo := r.Header.Get("Location"); lo != "" {
		ns.Location = lo
	}

	ns.Link = make(Links)
	for _, li := range r.Header["Link"] {
		re := linksRe.FindStringSubmatch(li)
		if len(re) == 3 {
			ns.Link[re[2]] = re[1]
		}
	}

	if ra := r.Header.Get("Retry-After"); ra != "" {
		n, err := strconv.Atoi(ra)
		if err == nil {
			ns.RetryAfter = time.Second * time.Duration(n)
		}
	}

	log.Println(ansi.Color("NEXT", "cyan"), ns)
	return ns
}

/*
                              directory
                                  .
                                  .
      ....................................................
      .                  .                  .            .
      .                  .                  .            .
      V     "next"       V      "next"      V            V
   new-reg ---+----> new-authz ---+----> new-cert    revoke-cert
      .       |          .        |         .            ^
      .       |          .        |         .            | "revoke"
      V       |          V        |         V            |
     reg* ----+        authz -----+       cert-----------+
                        . ^                 |
                        . | "up"            | "up"
                        V |                 V
                      challenge         cert-chain
*/

func (c *Client) Register(a *Account) error {
	r := &Registration{
		Resource: ResNewReg,
		Contact:  a.Contact,
	}
	resp, err := c.post(c.NewReg, a, r)
	if err != nil && err.(Problem).Err != ErrMalformed {
		return err
	}
	ns := parseHeader(resp)
	switch resp.StatusCode {
	case http.StatusConflict:
		// Query Location
		r = &Registration{Resource: ResRegister}
		resp, err = c.post(ns.Location, a, r)
		if err != nil {
			return err
		}
		fallthrough
	case http.StatusCreated:
		// Agree to TOS
		if tos := ns.Link["terms-of-service"]; tos != "" {
			r = &Registration{
				Resource:  ResRegister,
				Contact:   a.Contact,
				Agreement: tos,
			}
			_, err = c.post(ns.Location, a, r)
		}
	}
	return err
}

func (c *Client) Authorize(a *Account, domain []string) error {
	ident := Identifier{
		Type:  IdentDNS,
		Value: domain[0],
	}
	r := &Authorization{
		Resource:   ResNewAuthz,
		Identifier: ident,
	}
	resp, err := c.post(c.NewAuthz, a, r)
	if err != nil {
		return err
	}
	switch resp.StatusCode {
	case http.StatusCreated:
		for _, ch := range r.Challenges {
			if ch.Type == ChallengeHTTP {
				ans := &Challenge{
					Resource: ResChallenge,
					Type:     ch.Type,
					Token:    ch.Token,
				}
				_, err = c.post(ch.URI, a, ans)
			}
		}
	}
	return err
}

////////////////////////////////////////////////////////////////////////

// Register
// 1. new-reg
//    arg: contact
//    StatusCreated (201) or StatusConflict (409)
//    Response: Location, Link
// 2. reg
//    arg: contact, tos
//    StatusOk

// Authorize

// Certificate