Automatically post attachments. Addresses #7

.gitignore

@@ -13,6 +13,8 @@ config/production.yaml
 config/development.yaml
 test.eml
 
+db/attachments/*.attachment
+
 # Logs
 logs
 *.log

config/default.yaml

@@ -79,6 +79,37 @@ defaultRoomConfig:
   # being posted in the rough to the room.
   plaintextOnly: false
 
+  # Attachment processing settings
+  attachments:
+    # If true, the bot will post allowed attachments to the room
+    post: true
+
+    # If true, the bot will accept all types of attachments (ignoring whatever is defined
+    # in the allowedTypes list). Anything blocked by blockedTypes will not be sent.
+    allowAllTypes: false
+
+    # MIME type mapping to Matrix events. Defaults to m.file if not listed here.
+    # This is intended for advanced usage of the bot.
+    contentMapping:
+      "image/jpeg": "m.image"
+      "image/jpg": "m.image"
+      "image/png": "m.image"
+      "image/gif": "m.image"
+      "video/mp4": "m.video"
+      "audio/aac": "m.audio"
+
+    # The allowed MIME types to be posted to the room. Only applies if allowAllTypes is off
+    allowedTypes:
+    - 'image/png'
+    - 'image/jpeg'
+    - 'image/jpg'
+    - 'image/gif'
+    - 'application/pdf'
+
+    # The blocked MIME types. Attachments of these types will be skipped.
+    blockedTypes:
+    - 'application/exe'
+
   # If true, the bot will post fragments to the room. Fragments are replies, quoted parts of
   # the message, signatures, and other parts that don't appear to be part of the "primary"
   # message. By default this is turned off to avoid flooding the room with quoted messages.

db/attachments/README.txt

@@ -0,0 +1,2 @@
+This folder contains all of the saved attachments for messages. The file names are generated to avoid conflicts - please
+see the database to see which files belong to which messages.

migrations/20170302051233-add-attachments-table.js

@@ -0,0 +1,30 @@
+'use strict';
+
+var dbm;
+var type;
+var seed;
+
+/**
+ * We receive the dbmigrate dependency from dbmigrate initially.
+ * This enables us to not have to rely on NODE_PATH.
+ */
+exports.setup = function (options, seedLink) {
+    dbm = options.dbmigrate;
+    type = dbm.dataType;
+    seed = seedLink;
+};
+
+exports.up = function (db) {
+    return db.createTable('attachments', {
+        id: {type: 'string', primaryKey: true},
+        email_id: 'string'
+    });
+};
+
+exports.down = function (db) {
+    return db.dropTable('attachments');
+};
+
+exports._meta = {
+    "version": 1
+};

package.json

@@ -19,6 +19,7 @@
     "request": "^2.79.0",
     "sanitize-html": "^1.14.1",
     "sqlite3": "^3.1.8",
+    "streamifier": "^0.1.1",
     "striptags": "^3.0.1",
     "uuid": "^3.0.1"
   }

src/DataStore.js

@@ -2,6 +2,8 @@ var sqlite3 = require('sqlite3');
 var uuid = require("uuid");
 var DBMigrate = require("db-migrate");
 var log = require("npmlog");
+var fs = require("fs");
+var path = require("path");
 
 /**
  * Represents the storage mechanism for emails and other information
@@ -107,6 +109,26 @@ class DataStore {
         });
     }
 
+    /**
+     * Saves an attachment
+     * @param {{name: string, content: Buffer}} attachment the attachment to save
+     * @param {String} messageId the message ID to link the attachment to
+     */
+    saveAttachment(attachment, messageId) {
+        log.info("DataStore", "saveAttachment - Starting write for " + attachment.name);
+        return new Promise((resolve, reject) => {
+            var id = uuid.v4();
+            var target = path.join(".", "db", "attachments", id + ".attachment");
+            fs.writeFileSync(target, attachment.content);
+            log.info("DataStore", "saveAttachment - Attachment written to file: " + target);
+            this._db.run("INSERT INTO attachments (id, email_id) VALUES (?, ?)", id, messageId, function (generatedId, error) {
+                log.info("DataStore", "saveAttachment - Attachment saved to DB (" + (error ? false : true) + ": " + id + " to message " + messageId);
+                if (error)reject(error);
+                else resolve();
+            }.bind(this));
+        });
+    }
+
     /**
      * Retrieves a raw email message from the underlying storage system. For example, the database record for the email
      * @param {string} id the record ID to lookup

src/EmailHandler.js

@@ -152,6 +152,31 @@ class EmailHandler {
                         continue;
                     }
 
+                    var attachments = [];
+                    if (message.attachments) {
+                        var allowedTypes = (roomConfig["attachments"]["allowedTypes"] || []);
+                        var blockedTypes = (roomConfig["attachments"]["blockedTypes"] || []);
+                        for (var attachment of message.attachments) {
+                            if (!roomConfig["attachments"]["allowAllTypes"] && allowedTypes.indexOf(attachment.contentType) === -1) {
+                                log.warn("EmailHandler", "Not processing attachment '" + attachment.generatedFileName + "': Content type '" + attachment.contentType + "' is not allowed");
+                                continue;
+                            }
+
+                            if (blockedTypes.indexOf(attachment.contentType) !== -1) {
+                                log.warn("EmailHandler", "Not processing attachment '" + attachment.generatedFileName + "': Content type '" + attachment.contentType + "' is blocked");
+                                continue;
+                            }
+
+                            attachments.push({
+                                name: attachment.generatedFileName,
+                                content: attachment.content,
+                                post: roomConfig["attachments"]["post"],
+                                type: attachment.contentType
+                            });
+                        }
+                    } else log.warn("EmailHandler", "Not processing attachments: Either no attachments or posting is not permitted");
+                    log.info("EmailHandler", "Found " + attachments.length + " valid attachments");
+
                     rooms.push(roomConfig.roomId);
 
                     var contentTypeHeader = (message.headers['content-type'] || "text/plain").toLowerCase();
@@ -192,15 +217,29 @@ class EmailHandler {
                                 log.info("EmailHandler", "Message saved. Id = " + msg.id);
                                 matrix.postMessageToRoom(msg, roomConfig.roomId, msgType);
                                 msgType = MessageType.FRAGMENT;
+
+                                this._saveAttachments(attachments, msg);
                             });
                         }
                     }
+
+                    for (var attachment of attachments) {
+                        if (!attachment.post) continue;
+                        matrix.postAttachmentToRoom(attachment, roomConfig.roomId);
+                    }
                 }
             }
         }, err => {
             log.error("EmailHandler", "Error checking for message: " + err);
         });
     }
+
+    _saveAttachments(attachments, message) {
+        for (var attachment of attachments) {
+            log.info("EmailHandler", "Linking " + attachment.name + " to message " + message.id);
+            this._db.saveAttachment(attachment, message.id);
+        }
+    }
 }
 
 module.exports = EmailHandler;

src/MatrixHandler.js

@@ -4,6 +4,7 @@ var striptags = require("striptags");
 var log = require("npmlog");
 var util = require("./utils");
 var MessageType = require("./MessageType");
+var streamifier = require("streamifier");
 
 /**
  * Handles matrix traffic for the bot
@@ -111,6 +112,48 @@ class MatrixHandler {
         log.info("MatrixHandler", "Sending message to room " + roomId);
         this._client.sendMessage(roomId, mtxContent);
     }
+
+    /**
+     * Posts an email attachment to the room given
+     * @param {{name: string, content: Buffer, type: string}} attachment the attachment to post
+     * @param {String} roomId the room ID to post to
+     */
+    postAttachmentToRoom(attachment, roomId) {
+        log.info("MatrixHandler", "Posting attachment '" + attachment.name + "' to room " + roomId);
+        if (this._roomList.indexOf(roomId) === -1) {
+            log.warn("MatrixHandler", "Attempt to send message to room " + roomId + ", but not in that room");
+            return; // not in room - skip message
+        }
+
+        var config = util.getRoomConfig(roomId);
+        if (!config) {
+            log.error("MatrixHandler", "No configuration for room " + roomId + ", but a message was supposed to go there");
+            return;
+        }
+
+        var eventType = "m.file";
+        if (config["attachments"]["contentMapping"][attachment.type]) {
+            eventType = config["attachments"]["contentMapping"][attachment.type];
+        }
+
+        log.info("MatrixHandler", "Uploading attachment '" + attachment.name + "' to room " + roomId);
+        this._client.uploadContent({
+            stream: streamifier.createReadStream(attachment.content),
+            name: attachment.name
+        }).then(url => {
+            log.info("MatrixHandler", "Got MXC URL for '" + attachment.name + "': " + url);
+            var content = {
+                msgtype: eventType,
+                body: attachment.name,
+                url: JSON.parse(url).content_uri,
+                info: {
+                    mimetype: attachment.type
+                }
+            };
+            log.info("MatrixHandler", "Posting attachment '" + attachment.name + "' to room " + roomId + " as event type " + eventType);
+            this._client.sendMessage(roomId, content);
+        });
+    }
 }
 
 module.exports = MatrixHandler;