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gallery-dl/gallery_dl/formatter.py

421 lines
12 KiB
Python

# -*- coding: utf-8 -*-
# Copyright 2021-2023 Mike Fährmann
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
"""String formatters"""
import os
import time
import string
import _string
import datetime
import operator
from . import text, util
NONE = util.NONE
def parse(format_string, default=NONE, fmt=format):
key = format_string, default, fmt
try:
return _CACHE[key]
except KeyError:
pass
cls = StringFormatter
if format_string.startswith("\f"):
kind, _, format_string = format_string.partition(" ")
kind = kind[1:]
if kind == "T":
cls = TemplateFormatter
elif kind == "E":
cls = ExpressionFormatter
elif kind == "M":
cls = ModuleFormatter
elif kind == "F":
cls = FStringFormatter
formatter = _CACHE[key] = cls(format_string, default, fmt)
return formatter
class StringFormatter():
"""Custom, extended version of string.Formatter
This string formatter implementation is a mostly performance-optimized
variant of the original string.Formatter class. Unnecessary features have
been removed (positional arguments, unused argument check) and new
formatting options have been added.
Extra Conversions:
- "l": calls str.lower on the target value
- "u": calls str.upper
- "c": calls str.capitalize
- "C": calls string.capwords
- "g": calls text.slugify()
- "j": calls json.dumps
- "t": calls str.strip
- "T": calls util.datetime_to_timestamp_string()
- "d": calls text.parse_timestamp
- "s": calls str()
- "S": calls util.to_string()
- "U": calls urllib.parse.unescape
- "r": calls repr()
- "a": calls ascii()
- Example: {f!l} -> "example"; {f!u} -> "EXAMPLE"
# Go to _CONVERSIONS and _SPECIFIERS below to se all of them, read:
# https://github.com/mikf/gallery-dl/blob/master/docs/formatting.md
Extra Format Specifiers:
- "?<before>/<after>/":
Adds <before> and <after> to the actual value if it evaluates to True.
Otherwise the whole replacement field becomes an empty string.
Example: {f:?-+/+-/} -> "-+Example+-" (if "f" contains "Example")
-> "" (if "f" is None, 0, "")
- "L<maxlen>/<replacement>/":
Replaces the output with <replacement> if its length (in characters)
exceeds <maxlen>. Otherwise everything is left as is.
Example: {f:L5/too long/} -> "foo" (if "f" is "foo")
-> "too long" (if "f" is "foobar")
- "J<separator>/":
Joins elements of a list (or string) using <separator>
Example: {f:J - /} -> "a - b - c" (if "f" is ["a", "b", "c"])
- "R<old>/<new>/":
Replaces all occurrences of <old> with <new>
Example: {f:R /_/} -> "f_o_o_b_a_r" (if "f" is "f o o b a r")
"""
def __init__(self, format_string, default=NONE, fmt=format):
self.default = default
self.format = fmt
self.result = []
self.fields = []
for literal_text, field_name, format_spec, conv in \
_string.formatter_parser(format_string):
if literal_text:
self.result.append(literal_text)
if field_name:
self.fields.append((
len(self.result),
self._field_access(field_name, format_spec, conv),
))
self.result.append("")
if len(self.result) == 1:
if self.fields:
self.format_map = self.fields[0][1]
else:
self.format_map = lambda _: format_string
del self.result, self.fields
def format_map(self, kwdict):
"""Apply 'kwdict' to the initial format_string and return its result"""
result = self.result
for index, func in self.fields:
result[index] = func(kwdict)
return "".join(result)
def _field_access(self, field_name, format_spec, conversion):
fmt = self._parse_format_spec(format_spec, conversion)
if "|" in field_name:
return self._apply_list([
parse_field_name(fn)
for fn in field_name.split("|")
], fmt)
else:
key, funcs = parse_field_name(field_name)
if key in _GLOBALS:
return self._apply_globals(_GLOBALS[key], funcs, fmt)
if funcs:
return self._apply(key, funcs, fmt)
return self._apply_simple(key, fmt)
def _apply(self, key, funcs, fmt):
def wrap(kwdict):
try:
obj = kwdict[key]
for func in funcs:
obj = func(obj)
except Exception:
obj = self.default
return fmt(obj)
return wrap
def _apply_globals(self, gobj, funcs, fmt):
def wrap(_):
try:
obj = gobj()
for func in funcs:
obj = func(obj)
except Exception:
obj = self.default
return fmt(obj)
return wrap
def _apply_simple(self, key, fmt):
def wrap(kwdict):
return fmt(kwdict[key] if key in kwdict else self.default)
return wrap
def _apply_list(self, lst, fmt):
def wrap(kwdict):
for key, funcs in lst:
try:
obj = _GLOBALS[key]() if key in _GLOBALS else kwdict[key]
for func in funcs:
obj = func(obj)
if obj:
break
except Exception:
pass
else:
obj = self.default
return fmt(obj)
return wrap
def _parse_format_spec(self, format_spec, conversion):
fmt = _build_format_func(format_spec, self.format)
if not conversion:
return fmt
conversion = _CONVERSIONS[conversion]
if fmt is self.format:
return conversion
else:
return lambda obj: fmt(conversion(obj))
class TemplateFormatter(StringFormatter):
"""Read format_string from file"""
def __init__(self, path, default=NONE, fmt=format):
with open(util.expand_path(path)) as fp:
format_string = fp.read()
StringFormatter.__init__(self, format_string, default, fmt)
class ExpressionFormatter():
"""Generate text by evaluating a Python expression"""
def __init__(self, expression, default=NONE, fmt=None):
self.format_map = util.compile_expression(expression)
class ModuleFormatter():
"""Generate text by calling an external function"""
def __init__(self, function_spec, default=NONE, fmt=None):
module_name, _, function_name = function_spec.partition(":")
module = __import__(module_name)
self.format_map = getattr(module, function_name)
class FStringFormatter():
"""Generate text by evaluating an f-string literal"""
def __init__(self, fstring, default=NONE, fmt=None):
self.format_map = util.compile_expression("f'''" + fstring + "'''")
def parse_field_name(field_name):
first, rest = _string.formatter_field_name_split(field_name)
funcs = []
if first[0] == "'":
funcs.append(operator.itemgetter(first[1:-1]))
first = "_lit"
for is_attr, key in rest:
if is_attr:
func = operator.attrgetter
else:
func = operator.itemgetter
try:
if ":" in key:
key = _slice(key)
except TypeError:
pass # key is an integer
funcs.append(func(key))
return first, funcs
def _slice(indices):
start, _, stop = indices.partition(":")
stop, _, step = stop.partition(":")
return slice(
int(start) if start else None,
int(stop) if stop else None,
int(step) if step else None,
)
def _build_format_func(format_spec, default):
if format_spec:
return _FORMAT_SPECIFIERS.get(
format_spec[0], _default_format)(format_spec, default)
return default
def _parse_optional(format_spec, default):
before, after, format_spec = format_spec.split(_SEPARATOR, 2)
before = before[1:]
fmt = _build_format_func(format_spec, default)
def optional(obj):
return before + fmt(obj) + after if obj else ""
return optional
def _parse_slice(format_spec, default):
indices, _, format_spec = format_spec.partition("]")
slice = _slice(indices[1:])
fmt = _build_format_func(format_spec, default)
def apply_slice(obj):
return fmt(obj[slice])
return apply_slice
def _parse_maxlen(format_spec, default):
maxlen, replacement, format_spec = format_spec.split(_SEPARATOR, 2)
maxlen = text.parse_int(maxlen[1:])
fmt = _build_format_func(format_spec, default)
def mlen(obj):
obj = fmt(obj)
return obj if len(obj) <= maxlen else replacement
return mlen
def _parse_join(format_spec, default):
separator, _, format_spec = format_spec.partition(_SEPARATOR)
join = separator[1:].join
fmt = _build_format_func(format_spec, default)
def apply_join(obj):
if isinstance(obj, str):
return fmt(obj)
return fmt(join(obj))
return apply_join
def _parse_replace(format_spec, default):
old, new, format_spec = format_spec.split(_SEPARATOR, 2)
old = old[1:]
fmt = _build_format_func(format_spec, default)
def replace(obj):
return fmt(obj.replace(old, new))
return replace
def _parse_datetime(format_spec, default):
dt_format, _, format_spec = format_spec.partition(_SEPARATOR)
dt_format = dt_format[1:]
fmt = _build_format_func(format_spec, default)
def dt(obj):
return fmt(text.parse_datetime(obj, dt_format))
return dt
def _parse_offset(format_spec, default):
offset, _, format_spec = format_spec.partition(_SEPARATOR)
offset = offset[1:]
fmt = _build_format_func(format_spec, default)
if not offset or offset == "local":
is_dst = time.daylight and time.localtime().tm_isdst > 0
offset = -(time.altzone if is_dst else time.timezone)
else:
hours, _, minutes = offset.partition(":")
offset = 3600 * int(hours)
if minutes:
offset += 60 * (int(minutes) if offset > 0 else -int(minutes))
offset = datetime.timedelta(seconds=offset)
def off(obj):
return fmt(obj + offset)
return off
def _parse_sort(format_spec, default):
args, _, format_spec = format_spec.partition(_SEPARATOR)
fmt = _build_format_func(format_spec, default)
if "d" in args or "r" in args:
def sort_desc(obj):
return fmt(sorted(obj, reverse=True))
return sort_desc
else:
def sort_asc(obj):
return fmt(sorted(obj))
return sort_asc
def _default_format(format_spec, default):
def wrap(obj):
return format(obj, format_spec)
return wrap
class Literal():
# __getattr__, __getattribute__, and __class_getitem__
# are all slower than regular __getitem__
@staticmethod
def __getitem__(key):
return key
_literal = Literal()
_CACHE = {}
_SEPARATOR = "/"
_GLOBALS = {
"_env": lambda: os.environ,
"_lit": lambda: _literal,
"_now": datetime.datetime.now,
}
_CONVERSIONS = {
"l": str.lower,
"u": str.upper,
"c": str.capitalize,
"C": string.capwords,
"j": util.json_dumps,
"t": str.strip,
"T": util.datetime_to_timestamp_string,
"d": text.parse_timestamp,
"U": text.unescape,
"g": text.slugify,
"S": util.to_string,
"s": str,
"r": repr,
"a": ascii,
}
_FORMAT_SPECIFIERS = {
"?": _parse_optional,
"[": _parse_slice,
"D": _parse_datetime,
"L": _parse_maxlen,
"J": _parse_join,
"O": _parse_offset,
"R": _parse_replace,
"S": _parse_sort,
}