gotosocial/internal/transport/transport.go

146 lines
5.1 KiB
Go

// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package transport
import (
"context"
"crypto"
"errors"
"io"
"net/http"
"net/url"
"sync"
"time"
"github.com/go-fed/httpsig"
"github.com/superseriousbusiness/gotosocial/internal/gtscontext"
"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
"github.com/superseriousbusiness/gotosocial/internal/httpclient"
)
// Transport implements the pub.Transport interface with some additional functionality for fetching remote media.
//
// Since the transport has the concept of 'shortcuts' for fetching data locally rather than remotely, it is
// not *always* the case that calling a Transport function does an http call, but it usually will for remote
// hosts or resources for which a shortcut isn't provided by the transport controller (also in this package).
//
// For any of the transport functions, if a Fastfail context is passed in as the first parameter, the function
// will return after the first transport failure, instead of retrying + backing off.
type Transport interface {
/*
POST functions
*/
// Deliver sends an ActivityStreams object.
Deliver(ctx context.Context, b []byte, to *url.URL) error
// BatchDeliver sends an ActivityStreams object to multiple recipients.
BatchDeliver(ctx context.Context, b []byte, recipients []*url.URL) error
/*
GET functions
*/
// Dereference fetches the ActivityStreams object located at this IRI with a GET request.
Dereference(ctx context.Context, iri *url.URL) ([]byte, error)
// DereferenceMedia fetches the given media attachment IRI, returning the reader and filesize.
DereferenceMedia(ctx context.Context, iri *url.URL) (io.ReadCloser, int64, error)
// DereferenceInstance dereferences remote instance information, first by checking /api/v1/instance, and then by checking /.well-known/nodeinfo.
DereferenceInstance(ctx context.Context, iri *url.URL) (*gtsmodel.Instance, error)
// Finger performs a webfinger request with the given username and domain, and returns the bytes from the response body.
Finger(ctx context.Context, targetUsername string, targetDomain string) ([]byte, error)
}
// transport implements the Transport interface.
type transport struct {
controller *controller
pubKeyID string
privkey crypto.PrivateKey
signerExp time.Time
getSigner httpsig.Signer
postSigner httpsig.Signer
signerMu sync.Mutex
}
// GET will perform given http request using transport client, retrying on certain preset errors.
func (t *transport) GET(r *http.Request) (*http.Response, error) {
if r.Method != http.MethodGet {
return nil, errors.New("must be GET request")
}
ctx := r.Context() // extract, set pubkey ID.
ctx = gtscontext.SetOutgoingPublicKeyID(ctx, t.pubKeyID)
r = r.WithContext(ctx) // replace request ctx.
r.Header.Set("User-Agent", t.controller.userAgent)
return t.controller.client.DoSigned(r, t.signGET())
}
// POST will perform given http request using transport client, retrying on certain preset errors.
func (t *transport) POST(r *http.Request, body []byte) (*http.Response, error) {
if r.Method != http.MethodPost {
return nil, errors.New("must be POST request")
}
ctx := r.Context() // extract, set pubkey ID.
ctx = gtscontext.SetOutgoingPublicKeyID(ctx, t.pubKeyID)
r = r.WithContext(ctx) // replace request ctx.
r.Header.Set("User-Agent", t.controller.userAgent)
return t.controller.client.DoSigned(r, t.signPOST(body))
}
// signGET will safely sign an HTTP GET request.
func (t *transport) signGET() httpclient.SignFunc {
return func(r *http.Request) (err error) {
t.safesign(func() {
err = t.getSigner.SignRequest(t.privkey, t.pubKeyID, r, nil)
})
return
}
}
// signPOST will safely sign an HTTP POST request for given body.
func (t *transport) signPOST(body []byte) httpclient.SignFunc {
return func(r *http.Request) (err error) {
t.safesign(func() {
err = t.postSigner.SignRequest(t.privkey, t.pubKeyID, r, body)
})
return
}
}
// safesign will perform sign function within mutex protection,
// and ensured that httpsig.Signers are up-to-date.
func (t *transport) safesign(sign func()) {
// Perform within mu safety
t.signerMu.Lock()
defer t.signerMu.Unlock()
if now := time.Now(); now.After(t.signerExp) {
const expiry = 120
// Signers have expired and require renewal
t.getSigner, _ = NewGETSigner(expiry)
t.postSigner, _ = NewPOSTSigner(expiry)
t.signerExp = now.Add(time.Second * expiry)
}
// Perform signing
sign()
}