rfc1869.js

'use strict';
// RFC 1869 command parser

// 6.  MAIL FROM and RCPT TO Parameters
// [...]
//
//   esmtp-cmd        ::= inner-esmtp-cmd [SP esmtp-parameters] CR LF
//   esmtp-parameters ::= esmtp-parameter *(SP esmtp-parameter)
//   esmtp-parameter  ::= esmtp-keyword ["=" esmtp-value]
//   esmtp-keyword    ::= (ALPHA / DIGIT) *(ALPHA / DIGIT / "-")
//
//                        ; syntax and values depend on esmtp-keyword
//   esmtp-value      ::= 1*<any CHAR excluding "=", SP, and all
//                           control characters (US ASCII 0-31
//                           inclusive)>
//
//                        ; The following commands are extended to
//                        ; accept extended parameters.
//   inner-esmtp-cmd  ::= ("MAIL FROM:" reverse-path)   /
//                        ("RCPT TO:" forward-path)

/* eslint no-control-regex: 0 */
const chew_regexp = /\s+([A-Za-z0-9][A-Za-z0-9-]*(?:=[^= \x00-\x1f]+)?)$/;

exports.parse = (type, line, strict) => {
    let params = [];
    line = (new String(line)).replace(/\s*$/, '');
    if (type === "mail") {
        line = line.replace(strict ? /from:/i : /from:\s*/i, "");
    }
    else {
        line = line.replace(strict ? /to:/i : /to:\s*/i, "");
    }

    while (1) {
        const old_length = line.length;
        line = line.replace(chew_regexp, function repl (str, p1) {
            params.push(p1);
            return '';
        });
        if (old_length === line.length) {
            break;
        }
    }

    params = params.reverse();

    // the above will "fail" (i.e. all of the line in params) on
    // some addresses without <> like
    //    MAIL FROM: user=name@example.net
    // or RCPT TO: postmaster

    // let's see if $line contains nothing and use the first value as address:
    if (line.length) {
        // parameter syntax error, i.e. not all of the arguments were
        // stripped by the while() loop:
        if (line.match(/@.*\s/)) {
            throw new Error(`Syntax error in parameters ("${line}")`);
        }

        params.unshift(line);
    }

    line = params.shift() || '';
    if (strict) {
        if (!line.match(/^<.*>$/)) {
            throw new Error(`Invalid format of ${type} command: ${line}`);
        }
    }

    if (type === "mail") {
        if (!line.length) {
            return ["<>"]; // 'MAIL FROM:' --> 'MAIL FROM:<>'
        }
        if (line.match(/@.*\s/)) {
            throw new Error("Syntax error in parameters");
        }
    }
    else {
        // console.log("Looking at " + line);
        if (line.match(/@.*\s/)) {
            throw new Error("Syntax error in parameters");
        }
        else {
            if (line.match(/\s/)) {
                throw new Error("Syntax error in parameters");
            }
            else if (line.match(/@/)) {
                if (!line.match(/^<.*>$/)) {
                    line = `<${line}>`;
                }
            }
            else if (!line.match(/^(postmaster|abuse)$/i)) {
                throw new Error("Syntax error in address");
            }
        }
    }

    params.unshift(line);

    return params;
}