transaction.js

'use strict';
// An SMTP Transaction

// node.js built-in modules
const util   = require('util');

// haraka npm modules
const config = require('haraka-config');
const Notes  = require('haraka-notes');
const utils  = require('haraka-utils');

// Haraka modules
const Header = require('./mailheader').Header;
const body   = require('./mailbody');
const MessageStream = require('./messagestream');

const MAX_HEADER_LINES = config.get('max_header_lines') || 1000;

class Transaction {
    constructor () {
        this.uuid = null;
        this.mail_from = null;
        this.rcpt_to = [];
        this.header_lines = [];
        this.data_lines = [];
        this.attachment_start_hooks = [];
        this.banner = null;
        this.body_filters = [];
        this.data_bytes = 0;
        this.header_pos = 0;
        this.found_hb_sep = false;
        this.body = null;
        this.parse_body = false;
        this.notes = new Notes();
        this.header = new Header();
        this.message_stream = null;
        this.discard_data = false;
        this.resetting = false;
        this.rcpt_count = {
            accept: 0,
            tempfail: 0,
            reject: 0,
        }
        this.msg_status = undefined;
        this.data_post_start = null;
        this.data_post_delay = 0;
        this.encoding = 'utf8';
        this.mime_part_count = 0;
    }

    ensure_body () {
        if (this.body) return;

        this.body = new body.Body(this.header);
        this.body.on('mime_boundary', m => this.incr_mime_count());
        this.attachment_start_hooks.forEach(h => {
            this.body.on('attachment_start', h);
        });

        if (this.banner) {
            this.body.set_banner(this.banner);
        }

        for (const o of this.body_filters) {
            this.body.add_filter((ct, enc, buf) => {
                const re_match = (util.isRegExp(o.ct_match) && o.ct_match.test(ct.toLowerCase()));
                const ct_begins = ct.toLowerCase().indexOf(String(o.ct_match).toLowerCase()) === 0;
                if (re_match || ct_begins) return o.filter(ct, enc, buf);
            })
        }
    }

    add_data (line) {
        if (typeof line === 'string') { // This shouldn't ever happen.
            line = Buffer.from(line, this.encoding);
        }
        // is this the end of headers line?
        if (this.header_pos === 0 &&
            (line[0] === 0x0A || (line[0] === 0x0D && line[1] === 0x0A))) {
            this.header.parse(this.header_lines);
            this.header_pos = this.header_lines.length;
            this.found_hb_sep = true;
            if (this.parse_body) this.ensure_body();
        }
        else if (this.header_pos === 0) {
            // Build up headers
            if (this.header_lines.length < MAX_HEADER_LINES) {
                if (line[0] === 0x2E) line = line.slice(1); // Strip leading '.'
                this.header_lines.push(line.toString(this.encoding).replace(/\r\n$/, '\n'));
            }
        }
        else if (this.header_pos && this.parse_body) {
            let new_line = line;
            if (new_line[0] === 0x2E) new_line = new_line.slice(1); // Strip leading "."

            new_line = this.body.parse_more(new_line.toString(this.encoding).replace(/\r\n$/, '\n'));

            if (!new_line.length) return; // buffering for banners
        }

        if (!this.discard_data) this.message_stream.add_line(line);
    }

    end_data (cb) {
        if (!this.found_hb_sep && this.header_lines.length) {
            // Headers not parsed yet - must be a busted email
            // Strategy: Find the first line that doesn't look like a header.
            // Treat anything before that as headers, anything after as body.
            let header_pos = 0;
            for (let i = 0; i < this.header_lines.length; i++) {
                // Anything that doesn't match a header or continuation
                if (!/^(?:([^\s:]*):\s*([\s\S]*)$|[ \t])/.test(this.header_lines[i])) {
                    break;
                }
                header_pos = i;
            }
            const body_lines = this.header_lines.splice(header_pos + 1);
            this.header.parse(this.header_lines);
            this.header_pos = header_pos;
            if (this.parse_body) {
                this.ensure_body();
                for (let j = 0; j < body_lines.length; j++) {
                    this.body.parse_more(body_lines[j]);
                }
            }
        }
        if (this.header_pos && this.parse_body) {
            let data = this.body.parse_end();
            if (data.length) {
                data = data.toString(this.encoding)
                    .replace(/^\./gm, '..')
                    .replace(/\r?\n/gm, '\r\n');
                const line = Buffer.from(data, this.encoding);

                this.body.force_end();

                if (!this.discard_data) this.message_stream.add_line(line);
            }
        }

        if (this.discard_data) {
            cb();
        }
        else {
            this.message_stream.add_line_end(cb);
        }
    }

    add_header (key, value) {
        this.header.add_end(key, value);
        if (this.header_pos > 0) this.reset_headers();
    }

    add_leading_header (key, value) {
        this.header.add(key, value);
        if (this.header_pos > 0) this.reset_headers();
    }

    reset_headers () {
        const header_lines = this.header.lines();
        this.header_pos = header_lines.length;
    }

    remove_header (key) {
        this.header.remove(key);
        if (this.header_pos > 0) this.reset_headers();
    }

    attachment_hooks (start, data, end) {
        this.parse_body = true;
        this.attachment_start_hooks.push(start);
    }

    set_banner (text, html) {
        // throw "transaction.set_banner is currently non-functional";
        this.parse_body = true;
        if (!html) {
            html = text.replace(/\n/g, '<br/>\n');
        }
        this.banner = [text, html];
    }

    add_body_filter (ct_match, filter) {
        this.parse_body = true;
        this.body_filters.push({ ct_match, filter });
    }

    incr_mime_count (line) {
        this.mime_part_count++;
    }
}

exports.Transaction = Transaction;
exports.MAX_HEADER_LINES = MAX_HEADER_LINES;

exports.createTransaction = uuid => {
    const t = new Transaction();
    t.uuid = uuid || utils.uuid();
    // Initialize MessageStream here to pass in the UUID
    t.message_stream = new MessageStream(
        config.get('smtp.ini'), t.uuid, t.header.header_list);
    return t;
}