gtsocial-umbx

derefinstance.go (9632B)

---

 // 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/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/gtserror"
 	"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(ctx, "trying to dereference instance %s by /api/v1/instance", iri.Host)
 	i, err = dereferenceByAPIV1Instance(ctx, t, iri)
 	if err == nil {
 		log.Debugf(ctx, "successfully dereferenced instance using /api/v1/instance")
 		return i, nil
 	}
 	log.Debugf(ctx, "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(ctx, "trying to dereference instance %s by /.well-known/nodeinfo", iri.Host)
 	i, err = dereferenceByNodeInfo(ctx, t, iri)
 	if err == nil {
 		log.Debugf(ctx, "successfully dereferenced instance using /.well-known/nodeinfo")
 		return i, nil
 	}
 	log.Debugf(ctx, "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(ctx, "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, gtserror.NewFromResponse(resp)
 	}
 
 	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.InstanceV1{}
 	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:                    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, gtserror.NewFromResponse(resp)
 	}
 
 	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, gtserror.NewFromResponse(resp)
 	}
 
 	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
 }