move to ssb gofed fork (#298)

vendor/github.com/superseriousbusiness/activity/pub/transport.go

@@ -0,0 +1,207 @@
+package pub
+
+import (
+	"bytes"
+	"context"
+	"crypto"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"strings"
+	"sync"
+
+	"github.com/go-fed/httpsig"
+)
+
+const (
+	// acceptHeaderValue is the Accept header value indicating that the
+	// response should contain an ActivityStreams object.
+	acceptHeaderValue = "application/ld+json; profile=\"https://www.w3.org/ns/activitystreams\""
+)
+
+// isSuccess returns true if the HTTP status code is either OK, Created, or
+// Accepted.
+func isSuccess(code int) bool {
+	return code == http.StatusOK ||
+		code == http.StatusCreated ||
+		code == http.StatusAccepted
+}
+
+// Transport makes ActivityStreams calls to other servers in order to send or
+// receive ActivityStreams data.
+//
+// It is responsible for setting the appropriate request headers, signing the
+// requests if needed, and facilitating the traffic between this server and
+// another.
+//
+// The transport is exclusively used to issue requests on behalf of an actor,
+// and is never sending requests on behalf of the server in general.
+//
+// It may be reused multiple times, but never concurrently.
+type Transport interface {
+	// Dereference fetches the ActivityStreams object located at this IRI
+	// with a GET request.
+	Dereference(c context.Context, iri *url.URL) ([]byte, error)
+	// Deliver sends an ActivityStreams object.
+	Deliver(c context.Context, b []byte, to *url.URL) error
+	// BatchDeliver sends an ActivityStreams object to multiple recipients.
+	BatchDeliver(c context.Context, b []byte, recipients []*url.URL) error
+}
+
+// Transport must be implemented by HttpSigTransport.
+var _ Transport = &HttpSigTransport{}
+
+// HttpSigTransport makes a dereference call using HTTP signatures to
+// authenticate the request on behalf of a particular actor.
+//
+// No rate limiting is applied.
+//
+// Only one request is tried per call.
+type HttpSigTransport struct {
+	client       HttpClient
+	appAgent     string
+	gofedAgent   string
+	clock        Clock
+	getSigner    httpsig.Signer
+	getSignerMu  *sync.Mutex
+	postSigner   httpsig.Signer
+	postSignerMu *sync.Mutex
+	pubKeyId     string
+	privKey      crypto.PrivateKey
+}
+
+// NewHttpSigTransport returns a new Transport.
+//
+// It sends requests specifically on behalf of a specific actor on this server.
+// The actor's credentials are used to add an HTTP Signature to requests, which
+// requires an actor's private key, a unique identifier for their public key,
+// and an HTTP Signature signing algorithm.
+//
+// The client lets users issue requests through any HTTP client, including the
+// standard library's HTTP client.
+//
+// The appAgent uniquely identifies the calling application's requests, so peers
+// may aid debugging the requests incoming from this server. Note that the
+// agent string will also include one for go-fed, so at minimum peer servers can
+// reach out to the go-fed library to aid in notifying implementors of malformed
+// or unsupported requests.
+func NewHttpSigTransport(
+	client HttpClient,
+	appAgent string,
+	clock Clock,
+	getSigner, postSigner httpsig.Signer,
+	pubKeyId string,
+	privKey crypto.PrivateKey) *HttpSigTransport {
+	return &HttpSigTransport{
+		client:       client,
+		appAgent:     appAgent,
+		gofedAgent:   goFedUserAgent(),
+		clock:        clock,
+		getSigner:    getSigner,
+		getSignerMu:  &sync.Mutex{},
+		postSigner:   postSigner,
+		postSignerMu: &sync.Mutex{},
+		pubKeyId:     pubKeyId,
+		privKey:      privKey,
+	}
+}
+
+// Dereference sends a GET request signed with an HTTP Signature to obtain an
+// ActivityStreams value.
+func (h HttpSigTransport) Dereference(c context.Context, iri *url.URL) ([]byte, error) {
+	req, err := http.NewRequest("GET", iri.String(), nil)
+	if err != nil {
+		return nil, err
+	}
+	req = req.WithContext(c)
+	req.Header.Add(acceptHeader, acceptHeaderValue)
+	req.Header.Add("Accept-Charset", "utf-8")
+	req.Header.Add("Date", h.clock.Now().UTC().Format("Mon, 02 Jan 2006 15:04:05")+" GMT")
+	req.Header.Add("User-Agent", fmt.Sprintf("%s %s", h.appAgent, h.gofedAgent))
+	req.Header.Set("Host", iri.Host)
+	h.getSignerMu.Lock()
+	err = h.getSigner.SignRequest(h.privKey, h.pubKeyId, req, nil)
+	h.getSignerMu.Unlock()
+	if err != nil {
+		return nil, err
+	}
+	resp, err := h.client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("GET request to %s failed (%d): %s", iri.String(), resp.StatusCode, resp.Status)
+	}
+	return ioutil.ReadAll(resp.Body)
+}
+
+// Deliver sends a POST request with an HTTP Signature.
+func (h HttpSigTransport) Deliver(c context.Context, b []byte, to *url.URL) error {
+	req, err := http.NewRequest("POST", to.String(), bytes.NewReader(b))
+	if err != nil {
+		return err
+	}
+	req = req.WithContext(c)
+	req.Header.Add(contentTypeHeader, contentTypeHeaderValue)
+	req.Header.Add("Accept-Charset", "utf-8")
+	req.Header.Add("Date", h.clock.Now().UTC().Format("Mon, 02 Jan 2006 15:04:05")+" GMT")
+	req.Header.Add("User-Agent", fmt.Sprintf("%s %s", h.appAgent, h.gofedAgent))
+	req.Header.Set("Host", to.Host)
+	h.postSignerMu.Lock()
+	err = h.postSigner.SignRequest(h.privKey, h.pubKeyId, req, b)
+	h.postSignerMu.Unlock()
+	if err != nil {
+		return err
+	}
+	resp, err := h.client.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	if !isSuccess(resp.StatusCode) {
+		return fmt.Errorf("POST request to %s failed (%d): %s", to.String(), resp.StatusCode, resp.Status)
+	}
+	return nil
+}
+
+// BatchDeliver sends concurrent POST requests. Returns an error if any of the
+// requests had an error.
+func (h HttpSigTransport) BatchDeliver(c context.Context, b []byte, recipients []*url.URL) error {
+	var wg sync.WaitGroup
+	errCh := make(chan error, len(recipients))
+	for _, recipient := range recipients {
+		wg.Add(1)
+		go func(r *url.URL) {
+			defer wg.Done()
+			if err := h.Deliver(c, b, r); err != nil {
+				errCh <- err
+			}
+		}(recipient)
+	}
+	wg.Wait()
+	errs := make([]string, 0, len(recipients))
+outer:
+	for {
+		select {
+		case e := <-errCh:
+			errs = append(errs, e.Error())
+		default:
+			break outer
+		}
+	}
+	if len(errs) > 0 {
+		return fmt.Errorf("batch deliver had at least one failure: %s", strings.Join(errs, "; "))
+	}
+	return nil
+}
+
+// HttpClient sends http requests, and is an abstraction only needed by the
+// HttpSigTransport. The standard library's Client satisfies this interface.
+type HttpClient interface {
+	Do(req *http.Request) (*http.Response, error)
+}
+
+// HttpClient must be implemented by http.Client.
+var _ HttpClient = &http.Client{}