import ast import os import re from django.utils.translation import ugettext_lazy as _ from django.utils.functional import Promise from orchestra.utils.paths import get_project_dir class Remove(object): """ used to signal a setting remove """ pass def get_settings_file(): return os.path.join(get_project_dir(), 'settings.py') def _find_updates(changes, settings_file): """ find all updates needed for applying changes on settings_file content """ with open(settings_file, 'rb') as handler: p = ast.parse(handler.read()) updates = [] for elem in p.body: if updates and updates[-1][-1] is None: updates[-1][-1] = elem.lineno-1 targets = getattr(elem, 'targets', None) if targets: var_name = targets[0].id if var_name in changes: updates.append([var_name, elem.lineno, None]) return updates class LazyUgettextRepr(object): def __init__(self, value): self.value = value def __repr__(self): return '_("%s")' % self.value def __len__(self): return len(repr(self.value)) class NotSupported(object): def __repr__(self): return 'Serialization not supported' def __len__(self): return 0 def get_eval_context(): return { 'NotSupported': NotSupported, '_': _, } def serialize(obj, init=True): if isinstance(obj, NotSupported): return obj elif isinstance(obj, Promise): _obj = LazyUgettextRepr(obj) elif isinstance(obj, dict): _obj = {} for name, value in obj.items(): name = serialize(name, init=False) value = serialize(value, init=False) if isinstance(name, NotSupported) or isinstance(value, NotSupported): return NotSupported() _obj[name] = value elif isinstance(obj, (tuple, list)): _obj = [] for nested in obj: nested = serialize(nested, init=False) if isinstance(nested, NotSupported): return nested _obj.append(nested) _obj = type(obj)(_obj) elif isinstance(obj, (str, bool, int, float)): _obj = obj else: _obj = NotSupported() return repr(_obj) if init else _obj def _format_setting(name, value): if isinstance(value, Remove): return "" value = serialize(eval(value), get_eval_context()) return "{name} = {value}".format(name=name, value=value) def apply(changes, settings_file=get_settings_file()): """ returns settings_file content with applied changes """ updates = _find_updates(changes, settings_file) content = [] inside = False lineno = None if updates: name, lineno, end = updates.pop(0) # update existing variable declarations with open(settings_file, 'r') as handler: for num, line in enumerate(handler.readlines(), 1): line = line.rstrip() if num == lineno: value = changes.pop(name) line = _format_setting(name, value) if line: content.append(line) inside = True comments = [] lastend = end try: name, lineno, end = updates.pop(0) except IndexError: if lastend is None: break if not inside: content.append(line) else: # Discard lines since variable will be replaced # But save comments and blank lines if re.match(r'^\s*(#.*)*\s*$', line): comments.append(line) else: comments = [] # End of variable declaration if num == lastend: content.extend(comments) inside = False # insert new variables at the end of file for name, value in changes.items(): content.append(_format_setting(name, value)) return '\n'.join(content) def save(changes, settings_file=get_settings_file(), backup=True): """ apply changes to project.settings file, saving a backup """ new_settings = apply(changes, settings_file) tmp_settings_file = settings_file + '.tmp' with open(tmp_settings_file, 'w') as handle: handle.write(new_settings) if backup: os.rename(settings_file, settings_file + '.backup') os.rename(tmp_settings_file, settings_file)