@app.route('/')
def hello_world():
return 'Hello World!'第1步：
class Flask(_PackageBoundObject):
def route(self, rule, **options):
def decorator(f): #f = hello_world
#1.1获取别名
endpoint = options.pop('endpoint', None)
#1.2
self.add_url_rule(rule, endpoint, f, **options)
return f
return decorator
第1.2步：
class Flask(_PackageBoundObject):
def add_url_rule(self, rule, endpoint=None, view_func=None, **options):
#1.2.1如果别名是None，执行_endpoint_from_view_func函数
if endpoint is None:
endpoint = _endpoint_from_view_func(view_func)
#1.2.2 给endpoint赋值
options['endpoint'] = endpoint
#1.2.3 获取允许的请求方法
methods = options.pop('methods', None)
#1.2.4如果方法为None
if methods is None:
#默认为GET
methods = getattr(view_func, 'methods', None) or ('GET',)
#1.2.5如果方法是字符串，抛出异常： 必须是methods=["POST"]这样可迭代的
if isinstance(methods, string_types):
raise TypeError('Allowed methods have to be iterables of strings, '
'for example: @app.route(..., methods=["POST"])')
#1.2.6把方法变成大写
methods = set(item.upper() for item in methods)
#1.2.7把匹配url和允许请求的方法封装到了Rule的一个对象中
rule = self.url_rule_class(rule, methods=methods, **options)
#self.url_rule_class = Rul
#1.2.8
self.url_map.add(rule)
#self.url_map = Map()
if view_func is not None:
#1.2.9 此步完成后： {"别名"：被装饰的函数名}
self.view_functions[endpoint] = view_func
第1.2.1步：
def _endpoint_from_view_func(view_func):
#返回被装饰的函数名
return view_func.__name__
第1.2.8步：
class Map(object):
def add(self, rulefactory):
#1.2.8.1
for rule in rulefactory.get_rules(self):
#1.2.8.2 Rule对象进行re正则绑定
rule.bind(self)
#1.2.8.3 添加到self._rules列表中，此时列表中就有了url
self._rules.append(rule)
#1.2.8.4 此步完成后： {"别名"：url}
self._rules_by_endpoint.setdefault(rule.endpoint, []).append(rule)
第1.2.8.1步：
class Rule(RuleFactory):
def get_rules(self, map):
yield self
#返回Rule对
第1.2.8.2步：
class Rule(RuleFactory):
def bind(self, map, rebind=False):
#1.2.8.2.1
self.compile()
第1.2.8.2.1步： 看不懂，猜里面是把url进行了re正则处理
class Rule(RuleFactory):
def compile(self):
if self.map.host_matching:
domain_rule = self.host or ''
else:
domain_rule = self.subdomain or '' self._trace = []
self._converters = {}
self._static_weights = []
self._argument_weights = []
regex_parts = [] def _build_regex(rule):
index = 0
for converter, arguments, variable in parse_rule(rule):
if converter is None:
regex_parts.append(re.escape(variable))
self._trace.append((False, variable))
for part in variable.split('/'):
if part:
self._static_weights.append((index, -len(part)))
else:
if arguments:
c_args, c_kwargs = parse_converter_args(arguments)
else:
c_args = ()
c_kwargs = {}
convobj = self.get_converter(
variable, converter, c_args, c_kwargs)
regex_parts.append('(?P<%s>%s)' % (variable, convobj.regex))
self._converters[variable] = convobj
self._trace.append((True, variable))
self._argument_weights.append(convobj.weight)
self.arguments.add(str(variable))
index = index + 1 _build_regex(domain_rule)
regex_parts.append('\\|')
self._trace.append((False, '|'))
_build_regex(self.is_leaf and self.rule or self.rule.rstrip('/'))
if not self.is_leaf:
self._trace.append((False, '/')) if self.build_only:
return
regex = r'^%s%s$' % (
u''.join(regex_parts),
(not self.is_leaf or not self.strict_slashes) and
'(?<!/)(?P<__suffix__>/?)' or ''
)
self._regex = re.compile(regex, re.UNICODE)
到此为止：
路由规则列表里新增了一条绑定正则的rule ；{"别名"：rule} ；{"别名"：被装饰的函数名}