mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-12-12 18:10:49 +01:00
231 lines
7.9 KiB
Go
231 lines
7.9 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"
|
|
"encoding/xml"
|
|
"fmt"
|
|
"io"
|
|
"net/http"
|
|
"net/url"
|
|
|
|
apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
|
|
apiutil "github.com/superseriousbusiness/gotosocial/internal/api/util"
|
|
"github.com/superseriousbusiness/gotosocial/internal/gtserror"
|
|
)
|
|
|
|
// webfingerURLFor returns the URL to try a webfinger request against, as
|
|
// well as if the URL was retrieved from cache. When the URL is retrieved
|
|
// from cache we don't have to try and do host-meta discovery
|
|
func (t *transport) webfingerURLFor(targetDomain string) (string, bool) {
|
|
url := "https://" + targetDomain + "/.well-known/webfinger"
|
|
|
|
wc := t.controller.state.Caches.GTS.Webfinger
|
|
|
|
// We're doing the manual locking/unlocking here to be able to
|
|
// safely call Cache.Get instead of Get, as the latter updates the
|
|
// item expiry which we don't want to do here
|
|
wc.Lock()
|
|
item, ok := wc.Cache.Get(targetDomain)
|
|
wc.Unlock()
|
|
|
|
if ok {
|
|
url = item.Value
|
|
}
|
|
|
|
return url, ok
|
|
}
|
|
|
|
func prepWebfingerReq(ctx context.Context, loc, domain, username string) (*http.Request, error) {
|
|
req, err := http.NewRequestWithContext(ctx, http.MethodGet, loc, nil)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
value := url.QueryEscape("acct:" + username + "@" + domain)
|
|
req.URL.RawQuery = "resource=" + value
|
|
|
|
// Prefer application/jrd+json, fall back to application/json.
|
|
// See https://www.rfc-editor.org/rfc/rfc7033#section-10.2.
|
|
//
|
|
// Some implementations don't handle multiple accept headers properly,
|
|
// including Gin itself. So concat the accept header with a comma
|
|
// instead which seems to work reliably
|
|
req.Header.Add("Accept", string(apiutil.AppJRDJSON)+","+string(apiutil.AppJSON))
|
|
|
|
return req, nil
|
|
}
|
|
|
|
func (t *transport) Finger(ctx context.Context, targetUsername string, targetDomain string) ([]byte, error) {
|
|
// Generate new GET request
|
|
url, cached := t.webfingerURLFor(targetDomain)
|
|
req, err := prepWebfingerReq(ctx, url, targetDomain, targetUsername)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Perform the HTTP request
|
|
rsp, err := t.GET(req)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
defer rsp.Body.Close()
|
|
|
|
// Check if the request succeeded so we can bail out early or if we explicitly
|
|
// got a "this resource is gone" response which will happen when a user has
|
|
// deleted the account
|
|
if rsp.StatusCode == http.StatusOK || rsp.StatusCode == http.StatusGone {
|
|
if cached {
|
|
// If we got a response we consider successful on a cached URL, i.e one set
|
|
// by us later on when a host-meta based webfinger request succeeded, set it
|
|
// again here to renew the TTL
|
|
t.controller.state.Caches.GTS.Webfinger.Set(targetDomain, url)
|
|
}
|
|
|
|
if rsp.StatusCode == http.StatusGone {
|
|
return nil, fmt.Errorf("account has been deleted/is gone")
|
|
}
|
|
|
|
// Ensure that the incoming request content-type is expected.
|
|
if ct := rsp.Header.Get("Content-Type"); !apiutil.JSONJRDContentType(ct) {
|
|
err := gtserror.Newf("non webfinger type response: %s", ct)
|
|
return nil, gtserror.SetMalformed(err)
|
|
}
|
|
|
|
return io.ReadAll(rsp.Body)
|
|
}
|
|
|
|
// From here on out, we're handling different failure scenarios and
|
|
// deciding whether we should do a host-meta based fallback or not
|
|
|
|
// Response status codes >= 500 are returned as errors by the wrapped HTTP client.
|
|
//
|
|
// if (rsp.StatusCode >= 500 && rsp.StatusCode < 600) || cached {
|
|
// In case we got a 5xx, bail out irrespective of if the value
|
|
// was cached or not. The target may be broken or be signalling
|
|
// us to back-off.
|
|
//
|
|
// If it's any error but the URL was cached, bail out too
|
|
// return nil, gtserror.NewResponseError(rsp)
|
|
// }
|
|
|
|
// So far we've failed to get a successful response from the expected
|
|
// webfinger endpoint. Lets try and discover the webfinger endpoint
|
|
// through /.well-known/host-meta
|
|
host, err := t.webfingerFromHostMeta(ctx, targetDomain)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("failed to discover webfinger URL fallback for: %s through host-meta: %w", targetDomain, err)
|
|
}
|
|
|
|
// Check if the original and host-meta URL are the same. If they
|
|
// are there's no sense in us trying the request again as it just
|
|
// failed
|
|
if host == url {
|
|
return nil, fmt.Errorf("webfinger discovery on %s returned endpoint we already tried: %s", targetDomain, host)
|
|
}
|
|
|
|
// Now that we have a different URL for the webfinger
|
|
// endpoint, try the request against that endpoint instead
|
|
req, err = prepWebfingerReq(ctx, host, targetDomain, targetUsername)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Perform the HTTP request
|
|
rsp, err = t.GET(req)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
defer rsp.Body.Close()
|
|
|
|
if rsp.StatusCode != http.StatusOK {
|
|
// A HTTP 410 indicates we got a response to our webfinger query, but the resource
|
|
// we asked for is gone. This means the endpoint itself is valid and we should
|
|
// cache it for future queries to the same domain
|
|
if rsp.StatusCode == http.StatusGone {
|
|
t.controller.state.Caches.GTS.Webfinger.Set(targetDomain, host)
|
|
return nil, fmt.Errorf("account has been deleted/is gone")
|
|
}
|
|
// We've reached the end of the line here, both the original request
|
|
// and our attempt to resolve it through the fallback have failed
|
|
return nil, gtserror.NewFromResponse(rsp)
|
|
}
|
|
|
|
// Set the URL in cache here, since host-meta told us this should be the
|
|
// valid one, it's different from the default and our request to it did
|
|
// not fail in any manner
|
|
t.controller.state.Caches.GTS.Webfinger.Set(targetDomain, host)
|
|
|
|
return io.ReadAll(rsp.Body)
|
|
}
|
|
|
|
func (t *transport) webfingerFromHostMeta(ctx context.Context, targetDomain string) (string, error) {
|
|
// Build the request for the host-meta endpoint
|
|
hmurl := "https://" + targetDomain + "/.well-known/host-meta"
|
|
req, err := http.NewRequestWithContext(ctx, http.MethodGet, hmurl, nil)
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
|
|
// We're doing XML
|
|
req.Header.Add("Accept", string(apiutil.AppXML))
|
|
req.Header.Add("Accept", "application/xrd+xml")
|
|
|
|
// Perform the HTTP request
|
|
rsp, err := t.GET(req)
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
defer rsp.Body.Close()
|
|
|
|
// Doesn't look like host-meta is working for this instance
|
|
if rsp.StatusCode != http.StatusOK {
|
|
return "", fmt.Errorf("GET request for %s failed: %s", req.URL.String(), rsp.Status)
|
|
}
|
|
|
|
// Ensure that the incoming request content-type is expected.
|
|
if ct := rsp.Header.Get("Content-Type"); !apiutil.XMLXRDContentType(ct) {
|
|
err := gtserror.Newf("non host-meta type response: %s", ct)
|
|
return "", gtserror.SetMalformed(err)
|
|
}
|
|
|
|
e := xml.NewDecoder(rsp.Body)
|
|
var hm apimodel.HostMeta
|
|
if err := e.Decode(&hm); err != nil {
|
|
// We got something, but it's not a host-meta document we understand
|
|
return "", fmt.Errorf("failed to decode host-meta response for %s at %s: %w", targetDomain, req.URL.String(), err)
|
|
}
|
|
|
|
for _, link := range hm.Link {
|
|
// Based on what we currently understand, there should not be more than one
|
|
// of these with Rel="lrdd" in a host-meta document
|
|
if link.Rel == "lrdd" {
|
|
u, err := url.Parse(link.Template)
|
|
if err != nil {
|
|
return "", fmt.Errorf("lrdd link is not a valid url: %w", err)
|
|
}
|
|
// Get rid of the query template, we only want the scheme://host/path part
|
|
u.RawQuery = ""
|
|
urlStr := u.String()
|
|
return urlStr, nil
|
|
}
|
|
}
|
|
return "", fmt.Errorf("no webfinger URL found")
|
|
}
|