# Source code for sqlobject.util.csvimport

    """
    Import from a CSV file or directory of files.

    CSV files should have a header line that lists columns.  Headers can
    also be appended with ``:type`` to indicate the type of the field.
    ``escaped`` is the default, though it can be overridden by the importer.
    Supported types:

    ``:python``:
        A python expression, run through ``eval()``.  This can be a
        security risk, pass in ``allow_python=False`` if you don't want to
        allow it.

    ``:int``:
        Integer

    ``:float``:
        Float

    ``:str``:
        String

    ``:escaped``:
        A string with backslash escapes (note that you don't put quotation
        marks around the value)

    ``:base64``:
        A base64-encoded string

    ``:date``:
        ISO date, like YYYY-MM-DD; this can also be ``NOW+days`` or
        ``NOW-days``

    ``:datetime``:
        ISO date/time like YYYY-MM-DDTHH:MM:SS (either T or a space can be
        used to separate the time, and seconds are optional).  This can
        also be ``NOW+seconds`` or ``NOW-seconds``

    ``:bool``:
        Converts true/false/yes/no/on/off/1/0 to boolean value

    ``:ref``:
        This will be resolved to the ID of the object named in this column
        (None if the column is empty).  @@: Since there's no ordering,
        there's no way to promise the object already exists.

    You can also get back references to the objects if you have a special
    ``[name]`` column.

    Any column named ``[comment]`` or with no name will be ignored.

    In any column you can put ``[default]`` to exclude the value and use
    whatever default the class wants.  ``[null]`` will use NULL.

    Lines that begin with ``[comment]`` are ignored.
    """

    import csv
    from datetime import datetime, date, timedelta
    import os
    import time
    import types

    __all__ = ['load_csv_from_directory',
               'load_csv',
               'create_data']

    DEFAULT_TYPE = 'escaped'

    def create_data(data, class_getter, keyorder=None):
        """
        Create the ``data``, which is the return value from
        ``load_csv()``.  Classes will be resolved with the callable
        ``class_getter``; or if ``class_getter`` is a module then the
        class names will be attributes of that.

        Returns a dictionary of ``{object_name: object(s)}``, using the
        names from the ``[name]`` columns (if there are any).  If a name
        is used multiple times, you get a list of objects, not a single
        object.

        If ``keyorder`` is given, then the keys will be retrieved in that
        order.  It can be a list/tuple of names, or a sorting function.
        If not given and ``class_getter`` is a module and has a
        ``soClasses`` function, then that will be used for the order.
        """
        objects = {}
        classnames = data.keys()
        if (not keyorder and isinstance(class_getter, types.ModuleType)
                and hasattr(class_getter, 'soClasses')):
            keyorder = [c.__name__ for c in class_getter.soClasses]
        if not keyorder:
            classnames.sort()
        elif isinstance(keyorder, (list, tuple)):
            all = classnames
            classnames = [name for name in keyorder if name in classnames]
            for name in all:
                if name not in classnames:
                    classnames.append(name)
        else:
            classnames.sort(keyorder)
        for classname in classnames:
            items = data[classname]
            if not items:
                continue
            if isinstance(class_getter, types.ModuleType):
                soClass = getattr(class_getter, classname)
            else:
                soClass = class_getter(classname)
            for item in items:
                for key, value in item.items():
                    if isinstance(value, Reference):
                        resolved = objects.get(value.name)
                        if not resolved:
                            raise ValueError(
                                "Object reference to %r does not have target"
                                % value.name)
                        elif (isinstance(resolved, list) and len(resolved) > 1):
                            raise ValueError(
                                "Object reference to %r is ambiguous (got %r)"
                                % (value.name, resolved))
                        item[key] = resolved.id
                if '[name]' in item:
                    name = item.pop('[name]').strip()
                else:
                    name = None
                inst = soClass(**item)
                if name:
                    if name in objects:
                        if isinstance(objects[name], list):
                            objects[name].append(inst)
                        else:
                            objects[name] = [objects[name], inst]
                    else:
                        objects[name] = inst
        return objects

    def load_csv_from_directory(directory,
                                allow_python=True, default_type=DEFAULT_TYPE,
                                allow_multiple_classes=True):
        """
        Load the data from all the files in a directory.  Filenames
        indicate the class, with ``general.csv`` for data not associated
        with a class.  Return data just like ``load_csv`` does.

        This might cause problems on case-insensitive filesystems.
        """
        results = {}
        for filename in os.listdir(directory):
            base, ext = os.path.splitext(filename)
            if ext.lower() != '.csv':
                continue
            f = open(os.path.join(directory, filename), 'rb')
            csvreader = csv.reader(f)
            data = load_csv(csvreader, allow_python=allow_python,
                            default_type=default_type,
                            default_class=base,
                            allow_multiple_classes=allow_multiple_classes)
            f.close()
            for classname, items in data.items():
                results.setdefault(classname, []).extend(items)
        return results

    def load_csv(csvreader, allow_python=True, default_type=DEFAULT_TYPE,
                 default_class=None, allow_multiple_classes=True):
        """
        Loads the CSV file, returning a list of dictionaries with types
        coerced.
        """
        current_class = default_class
        current_headers = None
        results = {}

        for row in csvreader:
            if not [cell for cell in row if cell.strip()]:
                # empty row
                continue

            if row and row[0].strip() == 'CLASS:':
                if not allow_multiple_classes:
                    raise ValueError(
                        "CLASS: line in CSV file, but multiple classes "
                        "are not allowed in this file (line: %r)" % row)
                if not row[1:]:
                    raise ValueError(
                        "CLASS: in line in CSV file, with no class name "
                        "in next column (line: %r)" % row)
                current_class = row[1]
                current_headers = None
                continue

            if not current_class:
                raise ValueError(
                    "No CLASS: line given, and there is no default class "
                    "for this file (line: %r)" % row)

            if current_headers is None:
                current_headers = _parse_headers(row, default_type,
                                                 allow_python=allow_python)
                continue

            if row[0] == '[comment]':
                continue

            # Pad row with empty strings:
            row += [''] * (len(current_headers) - len(row))
            row_converted = {}
            for value, (name, coercer, args) in zip(row, current_headers):
                if name is None:
                    # Comment
                    continue
                if value == '[default]':
                    continue
                if value == '[null]':
                    row_converted[name] = None
                    continue
                args = (value,) + args
                row_converted[name] = coercer(*args)

            results.setdefault(current_class, []).append(row_converted)

        return results

    def _parse_headers(header_row, default_type, allow_python=True):
        headers = []
        for name in header_row:
            original_name = name
            if ':' in name:
                name, type = name.split(':', 1)
            else:
                type = default_type
            if type == 'python' and not allow_python:
                raise ValueError(
                    ":python header given when python headers are not allowed "
                    "(with header %r)" % original_name)
            name = name.strip()
            if name == '[comment]' or not name:
                headers.append((None, None, None))
                continue
            type = type.strip().lower()
            if '(' in type:
                type, arg = type.split('(', 1)
                if not arg.endswith(')'):
                    raise ValueError(
                        "Arguments (in ()'s) do not end with ): %r"
                        % original_name)
                args = (arg[:-1],)
            else:
                args = ()
            if name == '[name]':
                type = 'str'
            coercer, args = get_coercer(type)
            headers.append((name, coercer, args))
        return headers

    _coercers = {}

    def get_coercer(type):
        if type not in _coercers:
            raise ValueError(
                "Coercion type %r not known (I know: %s)"
                % (type, ', '.join(_coercers.keys())))
        return _coercers[type]

    def register_coercer(type, coercer, *args):
        _coercers[type] = (coercer, args)

    def identity(v):
        return v

    register_coercer('str', identity)
    register_coercer('string', identity)

    def decode_string(v, encoding):
        return v.decode(encoding)

    register_coercer('escaped', decode_string, 'string_escape')
    register_coercer('strescaped', decode_string, 'string_escape')
    register_coercer('base64', decode_string, 'base64')

    register_coercer('int', int)
    register_coercer('float', float)

    def parse_python(v):
        return eval(v, {}, {})

    register_coercer('python', parse_python)

    def parse_date(v):
        v = v.strip()
        if not v:
            return None
        if v.startswith('NOW-') or v.startswith('NOW+'):
            days = int(v[3:])
            now = date.today()
            return now + timedelta(days)
        else:
            parsed = time.strptime(v, '%Y-%m-%d')
            return date.fromtimestamp(time.mktime(parsed))

    register_coercer('date', parse_date)

    def parse_datetime(v):
        v = v.strip()
        if not v:
            return None
        if v.startswith('NOW-') or v.startswith('NOW+'):
            seconds = int(v[3:])
            now = datetime.now()
            return now + timedelta(0, seconds)
        else:
            fmts = ['%Y-%m-%dT%H:%M:%S',
                    '%Y-%m-%d %H:%M:%S',
                    '%Y-%m-%dT%H:%M',
                    '%Y-%m-%d %H:%M']
            for fmt in fmts[:-1]:
                try:
                    parsed = time.strptime(v, fmt)
                    break
                except ValueError:
                    pass
            else:
                parsed = time.strptime(v, fmts[-1])
            return datetime.fromtimestamp(time.mktime(parsed))

    register_coercer('datetime', parse_datetime)

    class Reference(object):
        def __init__(self, name):
            self.name = name

    def parse_ref(v):
        if not v.strip():
            return None
        else:
            return Reference(v)

    register_coercer('ref', parse_ref)

    def parse_bool(v):
        v = v.strip().lower()
        if v in ('y', 'yes', 't', 'true', 'on', '1'):
            return True
        elif v in ('n', 'no', 'f', 'false', 'off', '0'):
            return False
        raise ValueError(
            "Value is not boolean-like: %r" % v)

    register_coercer('bool', parse_bool)
    register_coercer('boolean', parse_bool)