Initial 'Note' support for ActivitiyPub/Mastodon, reconition of @User@domain ActivityPub addresses, skeleton for ActivityPub scan/toss

core/activitypub_activity.js

@@ -1,6 +1,20 @@
 const { isString, isObject } = require('lodash');
 const { v4: UUIDv4 } = require('uuid');
-const { ActivityStreamsContext } = require('./activitypub_util');
+const {
+    ActivityStreamsContext,
+    messageBodyToHtml,
+    selfUrl,
+} = require('./activitypub_util');
+const { Errors } = require('./enig_error');
+const User = require('./user');
+const Actor = require('./activitypub_actor');
+const { getISOTimestampString } = require('./database');
+const UserProps = require('./user_property');
+const { postJson } = require('./http_util');
+
+// deps
+const async = require('async');
+const _ = require('lodash');
 
 module.exports = class Activity {
     constructor(obj) {
@@ -47,7 +61,7 @@ module.exports = class Activity {
 
     // https://www.w3.org/TR/activitypub/#accept-activity-inbox
     static makeAccept(webServer, localActor, followRequest, id = null) {
-        id = id || webServer.buildUrl(`/${UUIDv4()}`);
+        id = id || Activity._makeId(webServer, '/accept');
 
         return new Activity({
             type: 'Accept',
@@ -56,7 +70,131 @@ module.exports = class Activity {
         });
     }
 
-    sendTo(actorUrl, cb) {
-        //  :TODO: https send |this| to actorUrl
+    static noteFromLocalMessage(webServer, message, cb) {
+        const localUserId = message.getLocalFromUserId();
+        if (!localUserId) {
+            return cb(Errors.UnexpectedState('Invalid user ID for local user!'));
+        }
+
+        async.waterfall(
+            [
+                callback => {
+                    return User.getUser(localUserId, callback);
+                },
+                (localUser, callback) => {
+                    const remoteActorAccount = message.getRemoteToUser();
+                    if (!remoteActorAccount) {
+                        return callback(
+                            Errors.UnexpectedState(
+                                'Message does not contain a remote address'
+                            )
+                        );
+                    }
+
+                    const opts = {};
+                    Actor.fromAccountName(
+                        remoteActorAccount,
+                        opts,
+                        (err, remoteActor) => {
+                            return callback(err, localUser, remoteActor);
+                        }
+                    );
+                },
+                (localUser, remoteActor, callback) => {
+                    Actor.fromLocalUser(localUser, webServer, (err, localActor) => {
+                        return callback(err, localUser, localActor, remoteActor);
+                    });
+                },
+                (localUser, localActor, remoteActor, callback) => {
+                    // we'll need the entire |activityId| as a linked reference later
+                    const activityId = Activity._makeId(webServer, '/create');
+
+                    // |remoteActor| is non-null if we fetchd it
+                    //const to = message.isPrivate() ? remoteActor ? remoteActor.id : `${ActivityStreamsContext}#Public`;
+
+                    // const obj = {
+                    //     '@context': ActivityStreamsContext,
+                    //     id: activityId,
+                    //     type: 'Create',
+                    //     to: [remoteActor.id],
+                    //     audience: ['as:Public'],
+                    //     actor: localActor.id,
+                    //     object: {
+                    //         id: Activity._makeId(webServer, '/note'),
+                    //         type: 'Note',
+                    //         attributedTo: localActor.id,
+                    //         to: [remoteActor.id],
+                    //         audience: ['as:Public'],
+                    //         content: messageBodyToHtml(message.message.trim()),
+                    //     },
+                    // };
+
+                    const obj = {
+                        '@context': ActivityStreamsContext,
+                        id: activityId,
+                        type: 'Create',
+                        actor: localActor.id,
+                        object: {
+                            id: Activity._makeId(webServer, '/note'),
+                            type: 'Note',
+                            published: getISOTimestampString(message.modTimestamp),
+                            attributedTo: localActor.id,
+                            // :TODO: inReplyto if this is a reply; we need this store in message meta.
+
+                            //  :TODO: we may want to turn this to a HTML fragment?
+                            content: messageBodyToHtml(message.message.trim()),
+                        },
+                    };
+
+                    //  :TODO: this probably needs to change quite a bit based on "groups"
+                    //  :TODO: verify we need both 'to' fields: https://socialhub.activitypub.rocks/t/problems-posting-to-mastodon-inbox/801/4
+                    if (message.isPrivate()) {
+                        obj.to = remoteActor.id;
+                        obj.object.to = remoteActor.id;
+                    } else {
+                        const publicInbox = `${ActivityStreamsContext}#Public`;
+                        obj.to = publicInbox;
+                        obj.object.to = publicInbox;
+                    }
+
+                    const activity = new Activity(obj);
+                    return callback(null, activity, localUser, remoteActor);
+                },
+            ],
+            (err, activity, fromUser, remoteActor) => {
+                return cb(err, { activity, fromUser, remoteActor });
+            }
+        );
+    }
+
+    sendTo(actorUrl, fromUser, webServer, cb) {
+        const privateKey = fromUser.getProperty(UserProps.PrivateKeyMain);
+        if (_.isEmpty(privateKey)) {
+            return cb(
+                Errors.MissingProperty(
+                    `User "${fromUser.username}" is missing the '${UserProps.PrivateKeyMain}' property`
+                )
+            );
+        }
+
+        const reqOpts = {
+            headers: {
+                'Content-Type': 'application/activity+json',
+            },
+            sign: {
+                //  :TODO: Make a helper for this
+                key: privateKey,
+                keyId: selfUrl(webServer, fromUser) + '#main-key',
+                authorizationHeaderName: 'Signature',
+                headers: ['(request-target)', 'host', 'date', 'digest', 'content-type'],
+            },
+        };
+
+        const activityJson = JSON.stringify(this);
+        return postJson(actorUrl, activityJson, reqOpts, cb);
+    }
+
+    static _makeId(webServer, prefix = '') {
+        return webServer.buildUrl(`${prefix}/${UUIDv4()}`);
     }
 };

core/activitypub_actor.js

@@ -4,7 +4,6 @@
 //  ENiGMA½
 const actorDb = require('./database.js').dbs.actor;
 const { Errors } = require('./enig_error.js');
-const { ActorProps } = require('./activitypub_actor_property');
 const UserProps = require('./user_property');
 const {
     webFingerProfileUrl,
@@ -14,9 +13,10 @@ const {
     ActivityStreamsContext,
 } = require('./activitypub_util');
 const Log = require('./logger').log;
+const { queryWebFinger } = require('./webfinger');
+const EnigAssert = require('./enigma_assert');
 
 //  deps
-const assert = require('assert');
 const async = require('async');
 const _ = require('lodash');
 const https = require('https');
@@ -102,6 +102,11 @@ module.exports = class Actor {
                 owner: userSelfUrl,
                 publicKeyPem,
             };
+
+            EnigAssert(
+                !_.isEmpty(user.getProperty(UserProps.PrivateKeyMain)),
+                'User has public key but no private key!'
+            );
         } else {
             Log.warn(
                 { username: user.username },
@@ -117,6 +122,8 @@ module.exports = class Actor {
             Accept: 'application/activity+json',
         };
 
+        //  :TODO: use getJson()
+
         https.get(url, { headers }, res => {
             if (res.statusCode !== 200) {
                 return cb(Errors.Invalid(`Bad HTTP status code: ${req.statusCode}`));
@@ -153,6 +160,35 @@ module.exports = class Actor {
         });
     }
 
+    static fromAccountName(actorName, options, cb) {
+        //  :TODO: cache first -- do we have an Actor for this account already with a OK TTL?
+
+        queryWebFinger(actorName, (err, res) => {
+            if (err) {
+                return cb(err);
+            }
+
+            // we need a link with 'application/activity+json'
+            const links = res.links;
+            if (!Array.isArray(links)) {
+                return cb(Errors.DoesNotExist('No "links" object in WebFinger response'));
+            }
+
+            const activityLink = links.find(l => {
+                return l.type === 'application/activity+json' && l.href?.length > 0;
+            });
+
+            if (!activityLink) {
+                return cb(
+                    Errors.DoesNotExist('No Activity link found in WebFinger response')
+                );
+            }
+
+            // we can now query the href value for an Actor
+            return Actor.fromRemoteUrl(activityLink.href, cb);
+        });
+    }
+
     static fromJson(json) {
         const parsed = JSON.parse(json);
         return new Actor(parsed);

core/activitypub_util.js

@@ -20,6 +20,7 @@ exports.selfUrl = selfUrl;
 exports.userFromAccount = userFromAccount;
 exports.accountFromSelfUrl = accountFromSelfUrl;
 exports.getUserProfileTemplatedBody = getUserProfileTemplatedBody;
+exports.messageBodyToHtml = messageBodyToHtml;
 
 //  :TODO: more info in default
 // this profile template is the *default* for both WebFinger
@@ -160,3 +161,12 @@ function getUserProfileTemplatedBody(
         }
     );
 }
+
+//
+//  Apply very basic HTML to a message following
+//  Mastodon's supported tags of 'p', 'br', 'a', and 'span':
+//  https://blog.joinmastodon.org/2018/06/how-to-implement-a-basic-activitypub-server/
+//
+function messageBodyToHtml(body) {
+    return `<p>${body.replace(/\r?\n/g, '<br>')}</p>`;
+}

core/enig_error.js

@@ -54,6 +54,8 @@ exports.Errors = {
     HttpError: (reason, reasonCode) =>
         new EnigError('HTTP error', -32013, reason, reasonCode),
     Timeout: (reason, reasonCode) => new EnigError('Timeout', -32014, reason, reasonCode),
+    MissingProperty: (reason, reasonCode) =>
+        new EnigError('Missing property', -32014, reason, reasonCode),
 };
 
 exports.ErrorReasons = {

core/fse.js

@@ -16,7 +16,11 @@ const { MessageAreaConfTempSwitcher } = require('./mod_mixins.js');
 const { isAnsi, stripAnsiControlCodes, insert } = require('./string_util.js');
 const { stripMciColorCodes, controlCodesToAnsi } = require('./color_codes.js');
 const Config = require('./config.js').get;
-const { getAddressedToInfo } = require('./mail_util.js');
+const {
+    getAddressedToInfo,
+    setExternalAddressedToInfo,
+    copyExternalAddressedToInfo,
+} = require('./mail_util.js');
 const Events = require('./events.js');
 const UserProps = require('./user_property.js');
 const SysProps = require('./system_property.js');
@@ -589,15 +593,9 @@ exports.FullScreenEditorModule =
                             self.replyToMessage &&
                             self.replyToMessage.isFromRemoteUser()
                         ) {
-                            self.message.setRemoteToUser(
-                                self.replyToMessage.meta.System[
-                                    Message.SystemMetaNames.RemoteFromUser
-                                ]
-                            );
-                            self.message.setExternalFlavor(
-                                self.replyToMessage.meta.System[
-                                    Message.SystemMetaNames.ExternalFlavor
-                                ]
+                            copyExternalAddressedToInfo(
+                                self.replyToMessage,
+                                self.message
                             );
                             return callback(null);
                         }
@@ -605,21 +603,16 @@ exports.FullScreenEditorModule =
                         //
                         //  Detect if the user is attempting to send to a remote mail type that we support
                         //
-                        //  :TODO: how to plug in support without tying to various types here? isSupportedExteranlType() or such
                         const addressedToInfo = getAddressedToInfo(
                             self.message.toUserName
                         );
-                        if (
-                            addressedToInfo.name &&
-                            Message.AddressFlavor.FTN === addressedToInfo.flavor
-                        ) {
-                            self.message.setRemoteToUser(addressedToInfo.remote);
-                            self.message.setExternalFlavor(addressedToInfo.flavor);
-                            self.message.toUserName = addressedToInfo.name;
+
+                        if (setExternalAddressedToInfo(addressedToInfo, self.message)) {
+                            // setExternalAddressedToInfo() did what we need
                             return callback(null);
                         }
 
-                        //  we need to look it up
+                        //  Local user -- we need to look it up
                         User.getUserIdAndNameByLookup(
                             self.message.toUserName,
                             (err, toUserId) => {

core/http_util.js

@@ -1,18 +1,46 @@
 const { Errors } = require('./enig_error.js');
 
 // deps
-const { isString, isObject } = require('lodash');
+const { isString, isObject, truncate } = require('lodash');
 const https = require('https');
 const httpSignature = require('http-signature');
 const crypto = require('crypto');
 
+exports.getJson = getJson;
 exports.postJson = postJson;
 
+function getJson(url, options, cb) {
+    const defaultOptions = {
+        method: 'GET',
+    };
+
+    options = Object.assign({}, defaultOptions, options);
+
+    //  :TODO: signing -- DRY this.
+
+    _makeRequest(url, options, (err, body, res) => {
+        if (err) {
+            return cb(err);
+        }
+
+        let parsed;
+        try {
+            parsed = JSON.parse(body);
+        } catch (e) {
+            return cb(e);
+        }
+
+        return cb(null, parsed, res);
+    });
+}
+
 function postJson(url, json, options, cb) {
     if (!isString(json)) {
         json = JSON.stringify(json);
     }
 
+    //  :TODO: DRY this method with _makeRequest()
+
     const defaultOptions = {
         method: 'POST',
         body: json,
@@ -32,6 +60,59 @@ function postJson(url, json, options, cb) {
 
     options.headers['Content-Length'] = json.length;
 
+    const req = https.request(url, options, res => {
+        let body = [];
+        res.on('data', d => {
+            body.push(d);
+        });
+
+        res.on('end', () => {
+            body = Buffer.concat(body).toString();
+
+            if (res.statusCode < 200 || res.statusCode > 299) {
+                return cb(
+                    Errors.HttpError(
+                        `HTTP error ${res.statusCode}: ${truncate(body, { length: 128 })}`
+                    ),
+                    body,
+                    res
+                );
+            }
+
+            return cb(null, body, res);
+        });
+    });
+
+    if (isObject(options.sign)) {
+        try {
+            httpSignature.sign(req, options.sign);
+        } catch (e) {
+            req.destroy();
+            return cb(Errors.Invalid(`Invalid signing material: ${e}`));
+        }
+    }
+
+    req.on('error', err => {
+        return cb(err);
+    });
+
+    req.on('timeout', () => {
+        req.destroy();
+        return cb(Errors.Timeout('Timeout making HTTP request'));
+    });
+
+    req.write(json);
+    req.end();
+}
+
+function _makeRequest(url, options, cb) {
+    if (options.body && options?.sign?.headers?.includes('digest')) {
+        options.headers['Digest'] = `SHA-256=${crypto
+            .createHash('sha256')
+            .update(options.body)
+            .digest('base64')}`;
+    }
+
     const req = https.request(url, options, res => {
         let body = [];
         res.on('data', d => {
@@ -67,6 +148,5 @@ function postJson(url, json, options, cb) {
         return cb(Errors.Timeout('Timeout making HTTP request'));
     });
 
-    req.write(json);
     req.end();
 }

core/mail_util.js

@@ -1,10 +1,14 @@
 /* jslint node: true */
 'use strict';
 
+const EnigmaAssert = require('./enigma_assert.js');
 const Address = require('./ftn_address.js');
+const { AddressFlavor } = require('./message.js');
 const Message = require('./message.js');
 
 exports.getAddressedToInfo = getAddressedToInfo;
+exports.setExternalAddressedToInfo = setExternalAddressedToInfo;
+exports.copyExternalAddressedToInfo = copyExternalAddressedToInfo;
 
 const EMAIL_REGEX =
     /^(([^<>()[\]\\.,;:\s@"]+(\.[^<>()[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
@@ -31,29 +35,29 @@ function getAddressedToInfo(input) {
     if (firstAtPos < 0) {
         let addr = Address.fromString(input);
         if (Address.isValidAddress(addr)) {
-            return { flavor: Message.AddressFlavor.FTN, remote: input };
+            return { flavor: AddressFlavor.FTN, remote: input };
         }
 
         const lessThanPos = input.indexOf('<');
         if (lessThanPos < 0) {
-            return { name: input, flavor: Message.AddressFlavor.Local };
+            return { name: input, flavor: AddressFlavor.Local };
         }
 
         const greaterThanPos = input.indexOf('>');
         if (greaterThanPos < lessThanPos) {
-            return { name: input, flavor: Message.AddressFlavor.Local };
+            return { name: input, flavor: AddressFlavor.Local };
         }
 
         addr = Address.fromString(input.slice(lessThanPos + 1, greaterThanPos));
         if (Address.isValidAddress(addr)) {
             return {
                 name: input.slice(0, lessThanPos).trim(),
-                flavor: Message.AddressFlavor.FTN,
+                flavor: AddressFlavor.FTN,
                 remote: addr.toString(),
             };
         }
 
-        return { name: input, flavor: Message.AddressFlavor.Local };
+        return { name: input, flavor: AddressFlavor.Local };
     }
 
     if (firstAtPos === 0) {
@@ -63,7 +67,7 @@ function getAddressedToInfo(input) {
             if (m) {
                 return {
                     name: input.slice(1, secondAtPos),
-                    flavor: Message.AddressFlavor.ActivityPub,
+                    flavor: AddressFlavor.ActivityPub,
                     remote: input.slice(firstAtPos),
                 };
             }
@@ -78,36 +82,67 @@ function getAddressedToInfo(input) {
         if (m) {
             return {
                 name: input.slice(0, lessThanPos).trim(),
-                flavor: Message.AddressFlavor.Email,
+                flavor: AddressFlavor.Email,
                 remote: addr,
             };
         }
 
-        return { name: input, flavor: Message.AddressFlavor.Local };
+        return { name: input, flavor: AddressFlavor.Local };
     }
 
     let m = input.match(EMAIL_REGEX);
     if (m) {
         return {
             name: input.slice(0, firstAtPos),
-            flavor: Message.AddressFlavor.Email,
+            flavor: AddressFlavor.Email,
             remote: input,
         };
     }
 
     let addr = Address.fromString(input); //  5D?
     if (Address.isValidAddress(addr)) {
-        return { flavor: Message.AddressFlavor.FTN, remote: addr.toString() };
+        return { flavor: AddressFlavor.FTN, remote: addr.toString() };
     }
 
     addr = Address.fromString(input.slice(firstAtPos + 1).trim());
     if (Address.isValidAddress(addr)) {
         return {
             name: input.slice(0, firstAtPos).trim(),
-            flavor: Message.AddressFlavor.FTN,
+            flavor: AddressFlavor.FTN,
             remote: addr.toString(),
         };
     }
 
-    return { name: input, flavor: Message.AddressFlavor.Local };
+    return { name: input, flavor: AddressFlavor.Local };
+}
+
+/// returns true if it's an external address
+function setExternalAddressedToInfo(addressInfo, message) {
+    const isValidAddressInfo = () => {
+        return addressInfo.name.length > 1 && addressInfo.remote.length > 1;
+    };
+
+    switch (addressInfo.flavor) {
+        case AddressFlavor.FTN:
+        case AddressFlavor.Email:
+        case AddressFlavor.QWK:
+        case AddressFlavor.NNTP:
+        case AddressFlavor.ActivityPub:
+            EnigmaAssert(isValidAddressInfo());
+
+            message.setRemoteToUser(addressInfo.remote);
+            message.setExternalFlavor(addressInfo.flavor);
+            message.toUserName = addressInfo.name;
+            return true;
+
+        default:
+        case AddressFlavor.Local:
+            return false;
+    }
+}
+
+function copyExternalAddressedToInfo(fromMessage, toMessage) {
+    const sm = Message.SystemMetaNames;
+    toMessage.setRemoteToUser(fromMessage.meta.System[sm.RemoteFromUser]);
+    toMessage.setExternalFlavor(fromMessage.meta.System[sm.ExternalFlavor]);
 }

core/message.js

@@ -101,6 +101,10 @@ const QWKPropertyNames = {
     InReplyToNum: 'qwk_in_reply_to_num', //  note that we prefer the 'InReplyToMsgId' kludge if available
 };
 
+const ActivityPubPropertyNames = {
+    ActivityId: 'activitypub_activity_id', //  Activity ID; FK to AP table entries
+};
+
 //  :TODO: this is a ugly hack due to bad variable names - clean it up & just _.camelCase(k)!
 const MESSAGE_ROW_MAP = {
     reply_to_message_id: 'replyToMsgId',
@@ -243,16 +247,29 @@ module.exports = class Message {
         this.meta.System[Message.SystemMetaNames.LocalFromUserID] = userId;
     }
 
+    getLocalFromUserId() {
+        let id = _.get(this, 'meta.System.local_from_user_id', 0);
+        return parseInt(id);
+    }
+
     setRemoteToUser(remoteTo) {
         this.meta.System = this.meta.System || {};
         this.meta.System[Message.SystemMetaNames.RemoteToUser] = remoteTo;
     }
 
+    getRemoteToUser() {
+        return _.get(this, 'meta.System.remote_to_user');
+    }
+
     setExternalFlavor(flavor) {
         this.meta.System = this.meta.System || {};
         this.meta.System[Message.SystemMetaNames.ExternalFlavor] = flavor;
     }
 
+    getAddressFlavor() {
+        return _.get(this, 'meta.System.external_flavor', Message.AddressFlavor.Local);
+    }
+
     static createMessageUUID(areaTag, modTimestamp, subject, body) {
         assert(_.isString(areaTag));
         assert(_.isDate(modTimestamp) || moment.isMoment(modTimestamp));

core/scanner_tossers/activitypub.js

@@ -0,0 +1,87 @@
+const Activity = require('../activitypub_activity');
+const Message = require('../message');
+const { MessageScanTossModule } = require('../msg_scan_toss_module');
+const { getServer } = require('../listening_server');
+
+exports.moduleInfo = {
+    name: 'ActivityPub',
+    desc: 'Provides ActivityPub scanner/tosser integration',
+    author: 'NuSkooler',
+};
+
+exports.getModule = class ActivityPubScannerTosser extends MessageScanTossModule {
+    constructor() {
+        super();
+    }
+
+    startup(cb) {
+        return cb(null);
+    }
+
+    shutdown(cb) {
+        return cb(null);
+    }
+
+    record(message) {
+        if (!this._isEnabled()) {
+            return;
+        }
+
+        Activity.noteFromLocalMessage(this._webServer(), message, (err, noteData) => {
+            if (err) {
+                // :TODO: Log me
+            }
+
+            const { activity, fromUser, remoteActor } = noteData;
+
+            // - persist Activity
+            // - sendTo
+            // - update message properties:
+            //  * exported
+            //  * ActivityPub ID -> activity table
+            activity.sendTo(
+                remoteActor.inbox,
+                fromUser,
+                this._webServer(),
+                (err, respBody, res) => {
+                    if (err) {
+                    }
+                }
+            );
+        });
+    }
+
+    _isEnabled() {
+        //  :TODO: check config to see if AP integration is enabled/etc.
+        return this._webServer();
+    }
+
+    _shouldExportMessage(message) {
+        //
+        // - Private messages: Must be ActivityPub flavor
+        // - Public messages: Must be in area mapped for ActivityPub import/export
+        //
+        //  :TODO: Implement the mapping
+        if (
+            Message.AddressFlavor.ActivityPub === message.getAddressFlavor() &&
+            Message.isPrivateAreaTag()
+        ) {
+            return true;
+        }
+
+        return false;
+    }
+
+    _exportToActivityPub(message, cb) {
+        return cb(null);
+    }
+
+    _webServer() {
+        // we have to lazy init
+        if (undefined === this.webServer) {
+            this.webServer = getServer('codes.l33t.enigma.web.server') || null;
+        }
+
+        return this.webServer ? this.webServer.instance : null;
+    }
+};

core/servers/content/web_handlers/activitypub.js

@@ -212,55 +212,27 @@ exports.getModule = class ActivityPubWebHandler extends WebHandlerModule {
                 //  request for the user to review and decide what to do with
                 //  at a later time.
                 //
+                //  :TODO: Implement the queue
                 const activityPubSettings = ActivityPubSettings.fromUser(user);
                 if (!activityPubSettings.manuallyApproveFollowers) {
-                    //
-                    //  :TODO: Implement the queue
                     Actor.fromLocalUser(user, this.webServer, (err, localActor) => {
                         if (err) {
-                            //  :TODO:
-                            return;
+                            return this.log.warn(
+                                { inbox: actor.inbox, error: err.message },
+                                'Failed to load local Actor for "Accept"'
+                            );
                         }
 
-                        //  user must have a Private Key
-                        const privateKey = user.getProperty(UserProps.PrivateKeyMain);
-                        if (_.isEmpty(privateKey)) {
-                            //  :TODO: Log me
-                            return;
-                        }
-
-                        //  :TODO: This stuff should probably be lifted out so it can be called ad-hoc from the queue
                         const accept = Activity.makeAccept(
                             this.webServer,
                             localActor,
                             activity
                         );
 
-                        const keyId = selfUrl(this.webServer, user) + '#main-key';
-
-                        const reqOpts = {
-                            headers: {
-                                'Content-Type': 'application/activity+json',
-                            },
-                            sign: {
-                                //  :TODO: Make a helper for this
-                                key: privateKey,
-                                keyId,
-                                authorizationHeaderName: 'Signature',
-                                headers: [
-                                    '(request-target)',
-                                    'host',
-                                    'date',
-                                    'digest',
-                                    'content-type',
-                                ],
-                            },
-                        };
-
-                        postJson(
+                        accept.sendTo(
                             actor.inbox,
-                            JSON.stringify(accept),
-                            reqOpts,
+                            user,
+                            this.webServer,
                             (err, respBody, res) => {
                                 if (err) {
                                     return this.log.warn(

core/system_view_validate.js

@@ -88,10 +88,8 @@ function validateGeneralMailAddressedTo(data, cb) {
     //  - Local username or real name
     //  - Supported remote flavors such as FTN, email, ...
     //
-    //  :TODO: remove hard-coded FTN check here. We need a decent way to register global supported flavors with modules.
     const addressedToInfo = getAddressedToInfo(data);
-
-    if (Message.AddressFlavor.FTN === addressedToInfo.flavor) {
+    if (Message.AddressFlavor.Local !== addressedToInfo.flavor) {
         return cb(null);
     }
 

core/webfinger.js

@@ -0,0 +1,49 @@
+const { Errors } = require('./enig_error');
+const { getAddressedToInfo } = require('./mail_util');
+const Message = require('./message');
+const { getJson } = require('./http_util');
+
+// deps
+const https = require('https');
+
+exports.queryWebFinger = queryWebFinger;
+
+function queryWebFinger(account, cb) {
+    // ex: @NuSkooler@toot.community -> https://toot.community/.well-known/webfinger with acct:NuSkooler resource
+    const addrInfo = getAddressedToInfo(account);
+    if (
+        addrInfo.flavor !== Message.AddressFlavor.ActivityPub &&
+        addrInfo.flavor !== Message.AddressFlavor.Email
+    ) {
+        return cb(Errors.Invalid(`Cannot WebFinger "${accountName}"; Missing domain`));
+    }
+
+    const domain = addrInfo.remote.slice(addrInfo.remote.lastIndexOf('@') + 1);
+    if (!domain) {
+        return cb(Errors.Invalid(`Cannot WebFinger "${accountName}"; Missing domain`));
+    }
+
+    const resource = encodeURIComponent(`acct:${account.slice(1)}`); // we need drop the initial '@' prefix
+    const webFingerUrl = `https://${domain}/.well-known/webfinger?resource=${resource}`;
+    getJson(webFingerUrl, {}, (err, json, res) => {
+        if (err) {
+            return cb(err);
+        }
+
+        if (res.statusCode !== 200) {
+            // only accept 200
+            return cb(Errors.DoesNotExist(`Failed to WebFinger URL ${webFingerUrl}`));
+        }
+
+        const contentType = res.headers['content-type'] || '';
+        if (!contentType.startsWith('application/jrd+json')) {
+            return cb(
+                Errors.Invalid(
+                    `Invalid Content-Type for WebFinger URL ${webFingerUrl}: ${contentType}`
+                )
+            );
+        }
+
+        return cb(null, json);
+    });
+}