# Buggy code
def send_mail(book_id, kindle_mail, calibrepath, user_id):
    """Send email with attachments"""
    book = db.session.query(db.Books).filter(db.Books.id == book_id).first()
    data = db.session.query(db.Data).filter(db.Data.book == book.id).all()

    formats = {}
    for entry in data:
        if entry.format == "MOBI":
            formats["mobi"] = entry.name + ".mobi"
        if entry.format == "EPUB":
            formats["epub"] = entry.name + ".epub"
        if entry.format == "PDF":
            formats["pdf"] = entry.name + ".pdf"

    if len(formats) == 0:
        return _("Could not find any formats suitable for sending by e-mail")

    if "mobi" in formats:
        result = formats["mobi"]
    elif "epub" in formats:
        # returns None if success, otherwise errormessage
        return convert_book_format(
            book_id, calibrepath, "epub", "mobi", user_id, kindle_mail
        )
    elif "pdf" in formats:
        result = formats["pdf"]  # worker.get_attachment()
    else:
        return _("Could not find any formats suitable for sending by e-mail")
    if result:
        global_WorkerThread.add_email(
            _("Send to Kindle"),
            book.path,
            result,
            ub.get_mail_settings(),
            kindle_mail,
            user_id,
            _("E-mail: %(book)s", book=book.title),
            _("This e-mail has been sent via Calibre-Web."),
        )
    else:
        return _("The requested file could not be read. Maybe wrong permissions?")


# Traceback (OperationalError)
ERROR:cps.web:Exception on /book/125 [GET]
Traceback (most recent call last):
File "/Users/jgillman/Code/calibre-web/vendor/flask/app.py", line 1817, in wsgi_app
response = self.full_dispatch_request()
File "/Users/jgillman/Code/calibre-web/vendor/flask/app.py", line 1477, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/Users/jgillman/Code/calibre-web/vendor/flask/app.py", line 1381, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/Users/jgillman/Code/calibre-web/vendor/flask/app.py", line 1475, in full_dispatch_request
rv = self.dispatch_request()
File "/Users/jgillman/Code/calibre-web/vendor/flask/app.py", line 1461, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/Users/jgillman/Code/calibre-web/vendor/flask_login.py", line 717, in decorated_view
return func(*args, **kwargs)
File "/Users/jgillman/Code/calibre-web/cps/web.py", line 381, in show_book
return render_template('detail.html', entry=entries,  cc=cc, title=entries.title, books_shelfs=book_in_shelfs)
File "/Users/jgillman/Code/calibre-web/vendor/flask/templating.py", line 128, in render_template
context, ctx.app)
File "/Users/jgillman/Code/calibre-web/vendor/flask/templating.py", line 110, in _render
rv = template.render(context)
File "/Users/jgillman/Code/calibre-web/vendor/jinja2/environment.py", line 969, in render
return self.environment.handle_exception(exc_info, True)
File "/Users/jgillman/Code/calibre-web/vendor/jinja2/environment.py", line 742, in handle_exception
reraise(exc_type, exc_value, tb)
File "/Users/jgillman/Code/calibre-web/cps/templates/detail.html", line 1, in top-level template code
{% extends "layout.html" %}
File "/Users/jgillman/Code/calibre-web/cps/templates/layout.html", line 136, in top-level template code
{% block body %}{% endblock %}
File "/Users/jgillman/Code/calibre-web/cps/templates/detail.html", line 66, in block "body"
{% if entry['custom_column_' ~ c.id]|length > 0 %}
File "/Users/jgillman/Code/calibre-web/vendor/jinja2/environment.py", line 387, in getitem
return getattr(obj, attr)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/orm/attributes.py", line 316, in __get__
return self.impl.get(instance_state(instance), dict_)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/orm/attributes.py", line 613, in get
value = self.callable_(state, passive)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/orm/strategies.py", line 524, in _load_for_state
return self._emit_lazyload(session, state, ident_key, passive)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/orm/strategies.py", line 585, in _emit_lazyload
result = q.all()
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/orm/query.py", line 2241, in all
return list(self)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/orm/query.py", line 2353, in __iter__
return self._execute_and_instances(context)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/orm/query.py", line 2368, in _execute_and_instances
result = conn.execute(querycontext.statement, self._params)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/engine/base.py", line 662, in execute
params)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/engine/base.py", line 761, in _execute_clauseelement
compiled_sql, distilled_params
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/engine/base.py", line 874, in _execute_context
context)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/engine/base.py", line 1024, in _handle_dbapi_exception
exc_info
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/util/compat.py", line 196, in raise_from_cause
reraise(type(exception), exception, tb=exc_tb)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/engine/base.py", line 867, in _execute_context
context)
File "/Users/jgillman/Code/calibre-web/vendor/sqlalchemy/engine/default.py", line 324, in do_execute
cursor.execute(statement, parameters)
OperationalError: (OperationalError) no such table: books_custom_column_1_link u'SELECT custom_column_1.id AS custom_column_1_id, custom_column_1.value AS custom_column_1_value \
nFROM custom_column_1, books_custom_column_1_link \nWHERE ? = books_custom_column_1_link.book AND custom_column_1.id = books_custom_column_1_link.value' (125,)
ERROR:tornado.access:500 GET /book/125 (::1) 89.60ms

# Fixed code
def send_mail(book_id, book_format, convert, kindle_mail, calibrepath, user_id):
    """Send email with attachments"""
    book = db.session.query(db.Books).filter(db.Books.id == book_id).first()

    if convert:
        # returns None if success, otherwise errormessage
        return convert_book_format(
            book_id, calibrepath, "epub", book_format.lower(), user_id, kindle_mail
        )
    else:
        for entry in iter(book.data):
            if entry.format.upper() == book_format.upper():
                result = entry.name + "." + book_format.lower()
                global_WorkerThread.add_email(
                    _("Send to Kindle"),
                    book.path,
                    result,
                    ub.get_mail_settings(),
                    kindle_mail,
                    user_id,
                    _("E-mail: %(book)s", book=book.title),
                    _("This e-mail has been sent via Calibre-Web."),
                )
                return
        return _("The requested file could not be read. Maybe wrong permissions?")