Serve outbox for Actor (#289)

* add statusesvisible convenience function

* add minID + onlyPublic to account statuses get

* move swagger collection stuff to common

* start working on Outbox GETting

* move functions into federationProcessor

* outboxToASCollection

* add statusesvisible convenience function

* add minID + onlyPublic to account statuses get

* move swagger collection stuff to common

* start working on Outbox GETting

* move functions into federationProcessor

* outboxToASCollection

* bit more work on outbox paging

* wrapNoteInCreate function

* test + hook up the processor functions

* don't do prev + next links on empty reply

* test get outbox through api

* don't fail on no status entries

* add outbox implementation doc

* typo

internal/processing/federation/getuser.go

@@ -0,0 +1,85 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 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 federation
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/url"
+
+	"github.com/go-fed/activity/streams"
+	"github.com/go-fed/activity/streams/vocab"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/util"
+)
+
+func (p *processor) GetUser(ctx context.Context, requestedUsername string, requestURL *url.URL) (interface{}, gtserror.WithCode) {
+	// get the account the request is referring to
+	requestedAccount, err := p.db.GetLocalAccountByUsername(ctx, requestedUsername)
+	if err != nil {
+		return nil, gtserror.NewErrorNotFound(fmt.Errorf("database error getting account with username %s: %s", requestedUsername, err))
+	}
+
+	var requestedPerson vocab.ActivityStreamsPerson
+	if util.IsPublicKeyPath(requestURL) {
+		// if it's a public key path, we don't need to authenticate but we'll only serve the bare minimum user profile needed for the public key
+		requestedPerson, err = p.tc.AccountToASMinimal(ctx, requestedAccount)
+		if err != nil {
+			return nil, gtserror.NewErrorInternalError(err)
+		}
+	} else if util.IsUserPath(requestURL) {
+		// if it's a user path, we want to fully authenticate the request before we serve any data, and then we can serve a more complete profile
+		requestingAccountURI, authenticated, err := p.federator.AuthenticateFederatedRequest(ctx, requestedUsername)
+		if err != nil || !authenticated {
+			return nil, gtserror.NewErrorNotAuthorized(errors.New("not authorized"), "not authorized")
+		}
+
+		// if we're not already handshaking/dereferencing a remote account, dereference it now
+		if !p.federator.Handshaking(ctx, requestedUsername, requestingAccountURI) {
+			requestingAccount, _, err := p.federator.GetRemoteAccount(ctx, requestedUsername, requestingAccountURI, false)
+			if err != nil {
+				return nil, gtserror.NewErrorNotAuthorized(err)
+			}
+
+			blocked, err := p.db.IsBlocked(ctx, requestedAccount.ID, requestingAccount.ID, true)
+			if err != nil {
+				return nil, gtserror.NewErrorInternalError(err)
+			}
+
+			if blocked {
+				return nil, gtserror.NewErrorNotAuthorized(fmt.Errorf("block exists between accounts %s and %s", requestedAccount.ID, requestingAccount.ID))
+			}
+		}
+
+		requestedPerson, err = p.tc.AccountToAS(ctx, requestedAccount)
+		if err != nil {
+			return nil, gtserror.NewErrorInternalError(err)
+		}
+	} else {
+		return nil, gtserror.NewErrorBadRequest(fmt.Errorf("path was not public key path or user path"))
+	}
+
+	data, err := streams.Serialize(requestedPerson)
+	if err != nil {
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
+	return data, nil
+}