gotosocial/internal/transport/derefinstance.go

323 lines
9.5 KiB
Go

/*
GoToSocial
Copyright (C) 2021-2023 GoToSocial Authors admin@gotosocial.org
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/json"
"errors"
"fmt"
"io"
"net/http"
"net/url"
"strings"
apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
apiutil "github.com/superseriousbusiness/gotosocial/internal/api/util"
"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
"github.com/superseriousbusiness/gotosocial/internal/id"
"github.com/superseriousbusiness/gotosocial/internal/log"
"github.com/superseriousbusiness/gotosocial/internal/util"
"github.com/superseriousbusiness/gotosocial/internal/validate"
)
func (t *transport) DereferenceInstance(ctx context.Context, iri *url.URL) (*gtsmodel.Instance, error) {
var i *gtsmodel.Instance
var err error
// First try to dereference using /api/v1/instance.
// This will provide the most complete picture of an instance, and avoid unnecessary api calls.
//
// This will only work with Mastodon-api compatible instances: Mastodon, some Pleroma instances, GoToSocial.
log.Debugf("trying to dereference instance %s by /api/v1/instance", iri.Host)
i, err = dereferenceByAPIV1Instance(ctx, t, iri)
if err == nil {
log.Debugf("successfully dereferenced instance using /api/v1/instance")
return i, nil
}
log.Debugf("couldn't dereference instance using /api/v1/instance: %s", err)
// If that doesn't work, try to dereference using /.well-known/nodeinfo.
// This will involve two API calls and return less info overall, but should be more widely compatible.
log.Debugf("trying to dereference instance %s by /.well-known/nodeinfo", iri.Host)
i, err = dereferenceByNodeInfo(ctx, t, iri)
if err == nil {
log.Debugf("successfully dereferenced instance using /.well-known/nodeinfo")
return i, nil
}
log.Debugf("couldn't dereference instance using /.well-known/nodeinfo: %s", err)
// we couldn't dereference the instance using any of the known methods, so just return a minimal representation
log.Debugf("returning minimal representation of instance %s", iri.Host)
id, err := id.NewRandomULID()
if err != nil {
return nil, fmt.Errorf("error creating new id for instance %s: %s", iri.Host, err)
}
return &gtsmodel.Instance{
ID: id,
Domain: iri.Host,
URI: iri.String(),
}, nil
}
func dereferenceByAPIV1Instance(ctx context.Context, t *transport, iri *url.URL) (*gtsmodel.Instance, error) {
cleanIRI := &url.URL{
Scheme: iri.Scheme,
Host: iri.Host,
Path: "api/v1/instance",
}
// Build IRI just once
iriStr := cleanIRI.String()
req, err := http.NewRequestWithContext(ctx, "GET", iriStr, nil)
if err != nil {
return nil, err
}
req.Header.Add("Accept", string(apiutil.AppJSON))
req.Header.Set("Host", cleanIRI.Host)
resp, err := t.GET(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", iriStr, resp.StatusCode, resp.Status)
}
b, err := io.ReadAll(resp.Body)
if err != nil {
return nil, err
} else if len(b) == 0 {
return nil, errors.New("response bytes was len 0")
}
// try to parse the returned bytes directly into an Instance model
apiResp := &apimodel.Instance{}
if err := json.Unmarshal(b, apiResp); err != nil {
return nil, err
}
var contactUsername string
if apiResp.ContactAccount != nil {
contactUsername = apiResp.ContactAccount.Username
}
ulid, err := id.NewRandomULID()
if err != nil {
return nil, err
}
i := &gtsmodel.Instance{
ID: ulid,
Domain: iri.Host,
Title: apiResp.Title,
URI: fmt.Sprintf("%s://%s", iri.Scheme, iri.Host),
ShortDescription: apiResp.ShortDescription,
Description: apiResp.Description,
ContactEmail: apiResp.Email,
ContactAccountUsername: contactUsername,
Version: apiResp.Version,
}
return i, nil
}
func dereferenceByNodeInfo(c context.Context, t *transport, iri *url.URL) (*gtsmodel.Instance, error) {
niIRI, err := callNodeInfoWellKnown(c, t, iri)
if err != nil {
return nil, fmt.Errorf("dereferenceByNodeInfo: error during initial call to well-known nodeinfo: %s", err)
}
ni, err := callNodeInfo(c, t, niIRI)
if err != nil {
return nil, fmt.Errorf("dereferenceByNodeInfo: error doing second call to nodeinfo uri %s: %s", niIRI.String(), err)
}
// we got a response of some kind! take what we can from it...
id, err := id.NewRandomULID()
if err != nil {
return nil, fmt.Errorf("dereferenceByNodeInfo: error creating new id for instance %s: %s", iri.Host, err)
}
// this is the bare minimum instance we'll return, and we'll add more stuff to it if we can
i := &gtsmodel.Instance{
ID: id,
Domain: iri.Host,
URI: iri.String(),
}
var title string
if i, present := ni.Metadata["nodeName"]; present {
// it's present, check it's a string
if v, ok := i.(string); ok {
// it is a string!
title = v
}
}
i.Title = title
var shortDescription string
if i, present := ni.Metadata["nodeDescription"]; present {
// it's present, check it's a string
if v, ok := i.(string); ok {
// it is a string!
shortDescription = v
}
}
i.ShortDescription = shortDescription
var contactEmail string
var contactAccountUsername string
if i, present := ni.Metadata["maintainer"]; present {
// it's present, check it's a map
if v, ok := i.(map[string]string); ok {
// see if there's an email in the map
if email, present := v["email"]; present {
if err := validate.Email(email); err == nil {
// valid email address
contactEmail = email
}
}
// see if there's a 'name' in the map
if name, present := v["name"]; present {
// name could be just a username, or could be a mention string eg @whatever@aaaa.com
username, _, err := util.ExtractNamestringParts(name)
if err == nil {
// it was a mention string
contactAccountUsername = username
} else {
// not a mention string
contactAccountUsername = name
}
}
}
}
i.ContactEmail = contactEmail
i.ContactAccountUsername = contactAccountUsername
var software string
if ni.Software.Name != "" {
software = ni.Software.Name
}
if ni.Software.Version != "" {
software = software + " " + ni.Software.Version
}
i.Version = software
return i, nil
}
func callNodeInfoWellKnown(ctx context.Context, t *transport, iri *url.URL) (*url.URL, error) {
cleanIRI := &url.URL{
Scheme: iri.Scheme,
Host: iri.Host,
Path: ".well-known/nodeinfo",
}
// Build IRI just once
iriStr := cleanIRI.String()
req, err := http.NewRequestWithContext(ctx, "GET", iriStr, nil)
if err != nil {
return nil, err
}
req.Header.Add("Accept", string(apiutil.AppJSON))
req.Header.Set("Host", cleanIRI.Host)
resp, err := t.GET(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
return nil, fmt.Errorf("callNodeInfoWellKnown: GET request to %s failed (%d): %s", iriStr, resp.StatusCode, resp.Status)
}
b, err := io.ReadAll(resp.Body)
if err != nil {
return nil, err
} else if len(b) == 0 {
return nil, errors.New("callNodeInfoWellKnown: response bytes was len 0")
}
wellKnownResp := &apimodel.WellKnownResponse{}
if err := json.Unmarshal(b, wellKnownResp); err != nil {
return nil, fmt.Errorf("callNodeInfoWellKnown: could not unmarshal server response as WellKnownResponse: %s", err)
}
// look through the links for the first one that matches the nodeinfo schema, this is what we need
var nodeinfoHref *url.URL
for _, l := range wellKnownResp.Links {
if l.Href == "" || !strings.HasPrefix(l.Rel, "http://nodeinfo.diaspora.software/ns/schema/2") {
continue
}
nodeinfoHref, err = url.Parse(l.Href)
if err != nil {
return nil, fmt.Errorf("callNodeInfoWellKnown: couldn't parse url %s: %s", l.Href, err)
}
}
if nodeinfoHref == nil {
return nil, errors.New("callNodeInfoWellKnown: could not find nodeinfo rel in well known response")
}
return nodeinfoHref, nil
}
func callNodeInfo(ctx context.Context, t *transport, iri *url.URL) (*apimodel.Nodeinfo, error) {
// Build IRI just once
iriStr := iri.String()
req, err := http.NewRequestWithContext(ctx, "GET", iriStr, nil)
if err != nil {
return nil, err
}
req.Header.Add("Accept", string(apiutil.AppJSON))
req.Header.Set("Host", iri.Host)
resp, err := t.GET(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
return nil, fmt.Errorf("callNodeInfo: GET request to %s failed (%d): %s", iriStr, resp.StatusCode, resp.Status)
}
b, err := io.ReadAll(resp.Body)
if err != nil {
return nil, err
} else if len(b) == 0 {
return nil, errors.New("callNodeInfo: response bytes was len 0")
}
niResp := &apimodel.Nodeinfo{}
if err := json.Unmarshal(b, niResp); err != nil {
return nil, fmt.Errorf("callNodeInfo: could not unmarshal server response as Nodeinfo: %s", err)
}
return niResp, nil
}