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/getoutbox.go

@@ -0,0 +1,107 @@
+/*
+   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/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+)
+
+func (p *processor) GetOutbox(ctx context.Context, requestedUsername string, page bool, maxID string, minID 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))
+	}
+
+	// authenticate the request
+	requestingAccountURI, authenticated, err := p.federator.AuthenticateFederatedRequest(ctx, requestedUsername)
+	if err != nil || !authenticated {
+		return nil, gtserror.NewErrorNotAuthorized(errors.New("not authorized"), "not authorized")
+	}
+
+	requestingAccount, _, err := p.federator.GetRemoteAccount(ctx, requestedUsername, requestingAccountURI, false)
+	if err != nil {
+		return nil, gtserror.NewErrorNotAuthorized(err)
+	}
+
+	// authorize the request:
+	// 1. check if a block exists between the requester and the requestee
+	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))
+	}
+
+	var data map[string]interface{}
+	// now there are two scenarios:
+	// 1. we're asked for the whole collection and not a page -- we can just return the collection, with no items, but a link to 'first' page.
+	// 2. we're asked for a specific page; this can be either the first page or any other page
+
+	if !page {
+		/*
+			scenario 1: return the collection with no items
+			we want something that looks like this:
+			{
+				"@context": "https://www.w3.org/ns/activitystreams",
+				"id": "https://example.org/users/whatever/outbox",
+				"type": "OrderedCollection",
+				"first": "https://example.org/users/whatever/outbox?page=true",
+				"last": "https://example.org/users/whatever/outbox?min_id=0&page=true"
+			}
+		*/
+		collection, err := p.tc.OutboxToASCollection(ctx, requestedAccount.OutboxURI)
+		if err != nil {
+			return nil, gtserror.NewErrorInternalError(err)
+		}
+
+		data, err = streams.Serialize(collection)
+		if err != nil {
+			return nil, gtserror.NewErrorInternalError(err)
+		}
+
+		return data, nil
+	}
+
+	// scenario 2 -- get the requested page
+	// limit pages to 30 entries per page
+	publicStatuses, err := p.db.GetAccountStatuses(ctx, requestedAccount.ID, 30, true, maxID, minID, false, false, true)
+	if err != nil && err != db.ErrNoEntries {
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
+	outboxPage, err := p.tc.StatusesToASOutboxPage(ctx, requestedAccount.OutboxURI, maxID, minID, publicStatuses)
+	if err != nil {
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+	data, err = streams.Serialize(outboxPage)
+	if err != nil {
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
+	return data, nil
+}