#!/usr/bin/env python # -*- coding: utf-8 -*- """ flask-07-upgrade ~~~~~~~~~~~~~~~~ This command line script scans a whole application tree and attempts to output an unified diff with all the changes that are necessary to easily upgrade the application to 0.7 and to not yield deprecation warnings. This will also attempt to find `after_request` functions that don't modify the response and appear to be better suited for `teardown_request`. This application is indeed an incredible hack, but because what it attempts to accomplish is impossible to do statically it tries to support the most common patterns at least. The diff it generates should be hand reviewed and not applied blindly without making backups. :copyright: (c) Copyright 2015 by Armin Ronacher. :license: see LICENSE for more details. """ from __future__ import print_function import re import os import inspect import difflib import posixpath from optparse import OptionParser try: import ast except ImportError: ast = None TEMPLATE_LOOKAHEAD = 4096 _app_re_part = r'((?:[a-zA-Z_][a-zA-Z0-9_]*app)|app|application)' _string_re_part = r"('([^'\\]*(?:\\.[^'\\]*)*)'" \ r'|"([^"\\]*(?:\\.[^"\\]*)*)")' _from_import_re = re.compile(r'^\s*from flask import\s+') _url_for_re = re.compile(r'\b(url_for\()(%s)' % _string_re_part) _render_template_re = re.compile(r'\b(render_template\()(%s)' % _string_re_part) _after_request_re = re.compile(r'((?:@\S+\.(?:app_)?))(after_request)(\b\s*$)(?m)') _module_constructor_re = re.compile(r'([a-zA-Z0-9_][a-zA-Z0-9_]*)\s*=\s*Module' r'\(__name__\s*(?:,\s*(?:name\s*=\s*)?(%s))?' % _string_re_part) _error_handler_re = re.compile(r'%s\.error_handlers\[\s*(\d+)\s*\]' % _app_re_part) _mod_route_re = re.compile(r'@([a-zA-Z0-9_][a-zA-Z0-9_]*)\.route') _blueprint_related = [ (re.compile(r'request\.module'), 'request.blueprint'), (re.compile(r'register_module'), 'register_blueprint'), (re.compile(r'%s\.modules' % _app_re_part), '\\1.blueprints') ] def make_diff(filename, old, new): for line in difflib.unified_diff(old.splitlines(), new.splitlines(), posixpath.normpath(posixpath.join('a', filename)), posixpath.normpath(posixpath.join('b', filename)), lineterm=''): print(line) def looks_like_teardown_function(node): returns = [x for x in ast.walk(node) if isinstance(x, ast.Return)] if len(returns) != 1: return return_def = returns[0] resp_name = node.args.args[0] if not isinstance(return_def.value, ast.Name) or \ return_def.value.id != resp_name.id: return for body_node in node.body: for child in ast.walk(body_node): if isinstance(child, ast.Name) and \ child.id == resp_name.id: if child is not return_def.value: return return resp_name.id def fix_url_for(contents, module_declarations=None): if module_declarations is None: skip_module_test = True else: skip_module_test = False mapping = dict(module_declarations) annotated_lines = [] def make_line_annotations(): if not annotated_lines: last_index = 0 for line in contents.splitlines(True): last_index += len(line) annotated_lines.append((last_index, line)) def backtrack_module_name(call_start): make_line_annotations() for idx, (line_end, line) in enumerate(annotated_lines): if line_end > call_start: for _, line in reversed(annotated_lines[:idx]): match = _mod_route_re.search(line) if match is not None: shortname = match.group(1) return mapping.get(shortname) def handle_match(match): if not skip_module_test: modname = backtrack_module_name(match.start()) if modname is None: return match.group(0) prefix = match.group(1) endpoint = ast.literal_eval(match.group(2)) if endpoint.startswith('.'): endpoint = endpoint[1:] elif '.' not in endpoint: endpoint = '.' + endpoint else: return match.group(0) return prefix + repr(endpoint) return _url_for_re.sub(handle_match, contents) def fix_teardown_funcs(contents): def is_return_line(line): args = line.strip().split() return args and args[0] == 'return' def fix_single(match, lines, lineno): if not lines[lineno + 1].startswith('def'): return block_lines = inspect.getblock(lines[lineno + 1:]) func_code = ''.join(block_lines) if func_code[0].isspace(): node = ast.parse('if 1:\n' + func_code).body[0].body else: node = ast.parse(func_code).body[0] response_param_name = looks_like_teardown_function(node) if response_param_name is None: return before = lines[:lineno] decorator = [match.group(1) + match.group(2).replace('after_', 'teardown_') + match.group(3)] body = [line.replace(response_param_name, 'exception') for line in block_lines if not is_return_line(line)] after = lines[lineno + len(block_lines) + 1:] return before + decorator + body + after content_lines = contents.splitlines(True) while 1: found_one = False for idx, line in enumerate(content_lines): match = _after_request_re.match(line) if match is None: continue new_content_lines = fix_single(match, content_lines, idx) if new_content_lines is not None: content_lines = new_content_lines break else: break return ''.join(content_lines) def get_module_autoname(filename): directory, filename = os.path.split(filename) if filename != '__init__.py': return os.path.splitext(filename)[0] return os.path.basename(directory) def rewrite_from_imports(prefix, fromlist, lineiter): import_block = [prefix, fromlist] if fromlist[0] == '(' and fromlist[-1] != ')': for line in lineiter: import_block.append(line) if line.rstrip().endswith(')'): break elif fromlist[-1] == '\\': for line in lineiter: import_block.append(line) if line.rstrip().endswith('\\'): break return ''.join(import_block).replace('Module', 'Blueprint') def rewrite_blueprint_imports(contents): new_file = [] lineiter = iter(contents.splitlines(True)) for line in lineiter: match = _from_import_re.search(line) if match is not None: new_file.extend(rewrite_from_imports(match.group(), line[match.end():], lineiter)) else: new_file.append(line) return ''.join(new_file) def rewrite_for_blueprints(contents, filename): modules_declared = [] def handle_match(match): target = match.group(1) name_param = match.group(2) if name_param is None: modname = get_module_autoname(filename) else: modname = ast.literal_eval(name_param) modules_declared.append((target, modname)) return '%s = %s' % (target, 'Blueprint(%r, __name__' % modname) new_contents = _module_constructor_re.sub(handle_match, contents) if modules_declared: new_contents = rewrite_blueprint_imports(new_contents) for pattern, replacement in _blueprint_related: new_contents = pattern.sub(replacement, new_contents) return new_contents, dict(modules_declared) def upgrade_python_file(filename, contents, teardown): new_contents = contents if teardown: new_contents = fix_teardown_funcs(new_contents) new_contents, modules = rewrite_for_blueprints(new_contents, filename) new_contents = fix_url_for(new_contents, modules) new_contents = _error_handler_re.sub('\\1.error_handler_spec[None][\\2]', new_contents) make_diff(filename, contents, new_contents) def upgrade_template_file(filename, contents): new_contents = fix_url_for(contents, None) make_diff(filename, contents, new_contents) def walk_path(path): this_file = os.path.realpath(__file__).rstrip('c') for dirpath, dirnames, filenames in os.walk(path): dirnames[:] = [x for x in dirnames if not x.startswith('.')] for filename in filenames: filename = os.path.join(dirpath, filename) if os.path.realpath(filename) == this_file: continue if filename.endswith('.py'): yield filename, 'python' # skip files that are diffs. These might be false positives # when run multiple times. elif not filename.endswith(('.diff', '.patch', '.udiff')): with open(filename) as f: contents = f.read(TEMPLATE_LOOKAHEAD) if '{% for' or '{% if' or '{{ url_for' in contents: yield filename, 'template' def scan_path(path=None, teardown=True): for filename, type in walk_path(path): with open(filename) as f: contents = f.read() if type == 'python': upgrade_python_file(filename, contents, teardown) elif type == 'template': upgrade_template_file(filename, contents) def main(): """Entrypoint""" parser = OptionParser(usage='%prog [options] [paths]') parser.add_option('-T', '--no-teardown-detection', dest='no_teardown', action='store_true', help='Do not attempt to ' 'detect teardown function rewrites.') parser.add_option('-b', '--bundled-templates', dest='bundled_tmpl', action='store_true', help='Indicate to the system ' 'that templates are bundled with modules. Default ' 'is auto detect.') options, args = parser.parse_args() if not args: args = ['.'] if ast is None: parser.error('Python 2.6 or later is required to run the upgrade script.') for path in args: scan_path(path, teardown=not options.no_teardown) if __name__ == '__main__': main()