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gotosocial/internal/transport/transport.go

198 lines
6.5 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/superseriousbusiness/gotosocial/internal/gtscontext"
"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
"github.com/superseriousbusiness/gotosocial/internal/httpclient"
"github.com/superseriousbusiness/gotosocial/internal/transport/delivery"
"github.com/superseriousbusiness/httpsig"
)
// 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
*/
// POST will perform given the http request using
// transport client, retrying on certain preset errors.
POST(*http.Request, []byte) (*http.Response, error)
// SignDelivery adds HTTP request signing client "middleware"
// to the request context within given delivery.Delivery{}.
SignDelivery(*delivery.Delivery) error
// Deliver sends an ActivityStreams object.
Deliver(ctx context.Context, obj map[string]interface{}, to *url.URL) error
// BatchDeliver sends an ActivityStreams object to multiple recipients.
BatchDeliver(ctx context.Context, obj map[string]interface{}, recipients []*url.URL) error
/*
GET functions
*/
// GET will perform the given http request using
// transport client, retrying on certain preset errors.
GET(*http.Request) (*http.Response, error)
// Dereference fetches the ActivityStreams object located at this IRI with a GET request.
Dereference(ctx context.Context, iri *url.URL) (*http.Response, error)
// DereferenceMedia fetches the given media attachment IRI, returning the reader limited to given max.
DereferenceMedia(ctx context.Context, iri *url.URL, maxsz int64) (io.ReadCloser, 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.SignerWithOptions
postSigner httpsig.SignerWithOptions
signerMu sync.Mutex
}
func (t *transport) GET(r *http.Request) (*http.Response, error) {
if r.Method != http.MethodGet {
return nil, errors.New("must be GET request")
}
// Prepare HTTP GET signing func with opts.
sign := t.signGET(httpsig.SignatureOption{
ExcludeQueryStringFromPathPseudoHeader: false,
})
ctx := r.Context() // update with signing details.
ctx = gtscontext.SetOutgoingPublicKeyID(ctx, t.pubKeyID)
ctx = gtscontext.SetHTTPClientSignFunc(ctx, sign)
r = r.WithContext(ctx) // replace request ctx.
// Set our predefined controller user-agent.
r.Header.Set("User-Agent", t.controller.userAgent)
// Pass to underlying HTTP client.
resp, err := t.controller.client.Do(r)
if err != nil || resp.StatusCode != http.StatusUnauthorized {
return resp, err
}
// Ignore this response.
_ = resp.Body.Close()
// Try again without the path included in
// the HTTP signature for better compatibility.
sign = t.signGET(httpsig.SignatureOption{
ExcludeQueryStringFromPathPseudoHeader: true,
})
ctx = r.Context() // update with signing details.
ctx = gtscontext.SetHTTPClientSignFunc(ctx, sign)
r = r.WithContext(ctx) // replace request ctx.
// Pass to underlying HTTP client.
return t.controller.client.Do(r)
}
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")
}
// Prepare POST signer.
sign := t.signPOST(body)
ctx := r.Context() // update with signing details.
ctx = gtscontext.SetOutgoingPublicKeyID(ctx, t.pubKeyID)
ctx = gtscontext.SetHTTPClientSignFunc(ctx, sign)
r = r.WithContext(ctx) // replace request ctx.
// Set our predefined controller user-agent.
r.Header.Set("User-Agent", t.controller.userAgent)
// Pass to underlying HTTP client.
return t.controller.client.Do(r)
}
// signGET will safely sign an HTTP GET request.
func (t *transport) signGET(opts httpsig.SignatureOption) httpclient.SignFunc {
return func(r *http.Request) (err error) {
t.safesign(func() {
err = t.getSigner.SignRequestWithOptions(t.privkey, t.pubKeyID, r, nil, opts)
})
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()
}