Tornado源码探寻(请求到来)
上一篇中介绍了tornado框架在客户端请求之前所做的准备（下图1、2部分），本质上就是创建了一个socket服务端，并进行了IP和端口的绑定，但是未执行 socket的accept方法，也就是未获取客户端请求信息。
概述:
本篇就来详细介绍tornado服务器（socket服务端）是如何接收用户请求数据以及如何根据用户请求的URL处理并返回数据，也就是上图的3系列所有步骤，如上图【start】是一个死循环，其中利用epoll监听服务端socket句柄，一旦客户端发送请求，则立即调用HttpServer对象的_handle_events方法来进行请求的处理。
对于整个3系列按照功能可以划分为四大部分：
- 获取用户请求数据（上图3.4）
- 根据用户请求URL进行路由匹配，从而使得某个方法处理具体的请求（上图3.5～3.19）
- 将处理后的数据返回给客户端（上图3.21～3.23）
- 关闭客户端socket（上图3.24～3.26）
3.1、HTTPServer对象的_handle_events方法
此处代码主要有三项任务：
1、 socket.accept() 接收了客户端请求。
2、创建封装了客户端socket对象和IOLoop对象的IOStream实例（用于之后获取或输出数据）。
3、创建HTTPConnection对象，其内容是实现整个功能的逻辑。
class HTTPServer(object):
def _handle_events(self, fd, events):
while True:
try:
#======== 获取客户端请求 =========#
connection, address = self._socket.accept()
except socket.error, e:
if e.args[0] in (errno.EWOULDBLOCK, errno.EAGAIN):
return
raise
if self.ssl_options is not None:
assert ssl, "Python 2.6+ and OpenSSL required for SSL"
try:
connection = ssl.wrap_socket(connection,
server_side=True,
do_handshake_on_connect=False,
**self.ssl_options)
except ssl.SSLError, err:
if err.args[0] == ssl.SSL_ERROR_EOF:
return connection.close()
else:
raise
except socket.error, err:
if err.args[0] == errno.ECONNABORTED:
return connection.close()
else:
raise
try:
#这是的条件是选择https和http请求方式
if self.ssl_options is not None:
stream = iostream.SSLIOStream(connection, io_loop=self.io_loop)
else:
#将客户端socket对象和IOLoop对象封装到IOStream对象中
#IOStream用于从客户端socket中读取请求信息
stream = iostream.IOStream(connection, io_loop=self.io_loop)
#创建HTTPConnection对象
#address是客户端IPdizhi
#self.request_callback是Application对象，其中包含了：url映射关系和配置文件等..
#so，HTTPConnection的构造函数就是下一步处理请求的位置了..
HTTPConnection(stream, address, self.request_callback,self.no_keep_alive, self.xheaders)
except:
logging.error("Error in connection callback", exc_info=True)
3.2、IOStream的__init__方法
此处代码主要两项目任务：
- 封装客户端socket和其他信息，以便之后执行该对象的其他方法获取客户端请求的数据和响应客户信息
- 将客户端socket对象添加到epoll，并且指定当客户端socket对象变化时，就去执行 IOStream的_handle_events方法（调用socket.send给用户响应数据）
class IOStream(object):
def __init__(self, socket, io_loop=None, max_buffer_size=104857600,
read_chunk_size=4096):
#客户端socket对象
self.socket = socket
self.socket.setblocking(False)
self.io_loop = io_loop or ioloop.IOLoop.instance()
self.max_buffer_size = max_buffer_size
self.read_chunk_size = read_chunk_size
self._read_buffer = collections.deque()
self._write_buffer = collections.deque()
self._write_buffer_frozen = False
self._read_delimiter = None
self._read_bytes = None
self._read_callback = None
self._write_callback = None
self._close_callback = None
self._connect_callback = None
self._connecting = False
self._state = self.io_loop.ERROR
with stack_context.NullContext():
#将客户端socket句柄添加的epoll中，并将IOStream的_handle_events方法添加到 Start 的While循环中
#Start 的While循环中监听客户端socket句柄的状态，以便再最后调用IOStream的_handle_events方法把处理后的信息响应给用户
self.io_loop.add_handler(self.socket.fileno(), self._handle_events, self._state)
3.3、HTTPConnections的__init__方法
此处代码主要两项任务：
- 获取请求数据
- 调用 _on_headers 继续处理请求
对于获取请求数据，其实就是执行IOStream的read_until函数来完成，其内部通过socket.recv(4096)方法获取客户端请求的数据，并以 【\r\n\r\n】作为请求信息结束符（http请求头和内容通过\r\n\r\n分割）。
class HTTPConnection(object):
def __init__(self, stream, address, request_callback, no_keep_alive=False,xheaders=False):
self.stream = stream #stream是封装了客户端socket和IOLoop实例的IOStream对象
self.address = address #address是客户端IP地址
self.request_callback = request_callback #request_callback是封装了URL映射和配置文件的Application对象。
self.no_keep_alive = no_keep_alive
self.xheaders = xheaders
self._request = None
self._request_finished = False
#获取请求信息（请求头和内容），然后执行 HTTPConnection的_on_headers方法继续处理请求
self._header_callback = stack_context.wrap(self._on_headers)
self.stream.read_until("\r\n\r\n", self._header_callback)
请求数据格式：
GET / HTTP/1.1
Host: localhost:8888
Connection: keep-alive
Cache-Control: max-age=0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
User-Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.118 Safari/537.36
Accept-Encoding: gzip, deflate, sdch
Accept-Language: zh-CN,zh;q=0.8,en;q=0.6,zh-TW;q=0.4
If-None-Match: "e02aa1b106d5c7c6a98def2b13005d5b84fd8dc8"
详细代码解析：
class IOStream(object):
def read_until(self, delimiter, callback):
"""Call callback when we read the given delimiter."""
assert not self._read_callback, "Already reading"
#终止界定 \r\n\r\n
self._read_delimiter = delimiter
#回调函数，即：HTTPConnection的 _on_headers 方法
self._read_callback = stack_context.wrap(callback)
while True:
#代码概述：
#先从socket中读取信息并保存到buffer中
#然后再读取buffer中的数据，以其为参数执行回调函数（HTTPConnection的 _on_headers 方法）
#buffer其实是一个线程安装的双端队列collections.deque
#从buffer中读取数据，并执行回调函数。
#注意：首次执行时buffer中没有数据
if self._read_from_buffer():
return
self._check_closed()
#从socket中读取信息到buffer（线程安全的一个双向消息队列）
if self._read_to_buffer() == 0:
break
self._add_io_state(self.io_loop.READ)
IOStream.read_until
class IOStream(object):
def _read_to_buffer(self):
#省略部分代码
chunk = self._read_from_socket()
self._read_buffer.append(chunk)
return len(chunk)
def _read_from_socket(self):
#socket对象的recv函数接收数据
#read_chunk_size在构造函数中默认设置为：4096
chunk = self.socket.recv(self.read_chunk_size)
if not chunk:
self.close()
return None
return chunk
IOStream._read_to_buffer
class IOStream(object):
def _read_from_buffer(self):
"""Attempts to complete the currently-pending read from the buffer.
Returns True if the read was completed.
"""
#构造函数中默认设置为None
if self._read_bytes:
if self._read_buffer_size() >= self._read_bytes:
num_bytes = self._read_bytes
callback = self._read_callback
self._read_callback = None
self._read_bytes = None
self._run_callback(callback, self._consume(num_bytes))
return True
#_read_delimiter的值为 \r\n\r\n
elif self._read_delimiter:
#buffer列表首元素合并，合并详细见_merge_prefix函数
_merge_prefix(self._read_buffer, sys.maxint)
#获取 \r\n\r\n 所在 buffer 首元素的位置索引
loc = self._read_buffer[0].find(self._read_delimiter)
if loc != -1:
#如果在请求中找到了 \r\n\r\n
#self._read_callback 是HTTPConnection对象的 _on_headers 方法
callback = self._read_callback
delimiter_len = len(self._read_delimiter) #获取 \r\n\r\n 的长度
self._read_callback = None
self._read_delimiter = None
#============ 执行HTTPConnection对象的 _on_headers 方法 =============
#self._consume(loc + delimiter_len)用来获取 buffer 的首元素（请求的信息其实就被封装到了buffer的首个元素中）
self._run_callback(callback,self._consume(loc + delimiter_len))
return True
return False
IOStream._read_from_buffer
3.4、HTTPConnnection的 _on_headers 方法（含3.5）
上述代码主要有两个任务：
- 根据获取的请求信息生成响应的请求头键值对，并把信息封装到HttpRequest对象中
- 调用Application的__call__方法，继续处理请求
class HTTPConnection(object):
def _on_headers(self, data):
try:
data = native_str(data.decode('latin1'))
eol = data.find("\r\n")
#获取请求的起始行数据，例如：GET / HTTP/1.1
start_line = data[:eol]
try:
#请求方式、请求地址、http版本号
method, uri, version = start_line.split(" ")
except ValueError:
raise _BadRequestException("Malformed HTTP request line")
if not version.startswith("HTTP/"):
raise _BadRequestException("Malformed HTTP version in HTTP Request-Line")
#把请求头信息包装到一个字典中。（不包括第一行）
headers = httputil.HTTPHeaders.parse(data[eol:]) #把请求信息封装到一个HTTPRequest对象中
#注意：self._request = HTTPRequest，
#HTTPRequest中封装了HTTPConnection
#HTTPConnection中封装了stream和application
self._request = HTTPRequest(connection=self, method=method, uri=uri, version=version,headers=headers, remote_ip=self.address[0])
#从请求头中获取 Content-Length
content_length = headers.get("Content-Length")
if content_length:
content_length = int(content_length)
if content_length > self.stream.max_buffer_size:
raise _BadRequestException("Content-Length too long")
if headers.get("Expect") == "100-continue":
self.stream.write("HTTP/1.1 100 (Continue)\r\n\r\n")
self.stream.read_bytes(content_length, self._on_request_body)
return
#**************** 执行Application对象的 __call__ 方法，也就是路由系统的入口 *******************
self.request_callback(self._request)
except _BadRequestException, e:
logging.info("Malformed HTTP request from %s: %s",
self.address[0], e)
self.stream.close()
return
class HTTPRequest(object):
def __init__(self, method, uri, version="HTTP/1.0", headers=None,
body=None, remote_ip=None, protocol=None, host=None,
files=None, connection=None):
self.method = method
self.uri = uri
self.version = version
self.headers = headers or httputil.HTTPHeaders()
self.body = body or ""
if connection and connection.xheaders:
# Squid uses X-Forwarded-For, others use X-Real-Ip
self.remote_ip = self.headers.get(
"X-Real-Ip", self.headers.get("X-Forwarded-For", remote_ip))
# AWS uses X-Forwarded-Proto
self.protocol = self.headers.get(
"X-Scheme", self.headers.get("X-Forwarded-Proto", protocol))
if self.protocol not in ("http", "https"):
self.protocol = "http"
else:
self.remote_ip = remote_ip
if protocol:
self.protocol = protocol
elif connection and isinstance(connection.stream,
iostream.SSLIOStream):
self.protocol = "https"
else:
self.protocol = "http"
self.host = host or self.headers.get("Host") or "127.0.0.1"
self.files = files or {}
self.connection = connection
self._start_time = time.time()
self._finish_time = None
scheme, netloc, path, query, fragment = urlparse.urlsplit(uri)
self.path = path
self.query = query
arguments = cgi.parse_qs(query)
self.arguments = {}
for name, values in arguments.iteritems():
values = [v for v in values if v]
if values: self.arguments[name] = values
HTTPRequest.__init__
3.6、Application的__call__方法(含3.7、3.8、3.9)
此处代码主要有三个项任务：
- 根据请求的url和封装在Application对象中的url映射做匹配，获取url所对应的Handler对象。ps：Handlers泛指继承RequestHandler的类
- 创建Handler对象，即：执行Handler的__init__方法
- 执行Handler对象的 _execute 方法
注意：
1、执行Application的 __call__ 方法时，其参数request是HTTPRequest对象（其中封装HTTPConnetion、Stream、Application对象、请求头信息）
2、Handler泛指就是我们定义的用于处理请求的类并且她还继承自RequestHandler
class Application(object):
def __call__(self, request):
"""Called by HTTPServer to execute the request."""
transforms = [t(request) for t in self.transforms]
handler = None
args = []
kwargs = {}
#根据请求的目标主机，匹配主机模版对应的正则表达式和Handlers
handlers = self._get_host_handlers(request)
if not handlers:
handler = RedirectHandler(
self, request, url="http://" + self.default_host + "/")
else:
for spec in handlers:
match = spec.regex.match(request.path)
if match:
# None-safe wrapper around url_unescape to handle
# unmatched optional groups correctly
def unquote(s):
if s is None: return s
return escape.url_unescape(s, encoding=None)
handler = spec.handler_class(self, request, **spec.kwargs) #创建RquestHandler对象
# Pass matched groups to the handler. Since
# match.groups() includes both named and unnamed groups,
# we want to use either groups or groupdict but not both.
# Note that args are passed as bytes so the handler can
# decide what encoding to use.
kwargs = dict((k, unquote(v))
for (k, v) in match.groupdict().iteritems())
if kwargs:
args = []
else:
args = [unquote(s) for s in match.groups()]
break
if not handler:
handler = ErrorHandler(self, request, status_code=404)
# In debug mode, re-compile templates and reload static files on every
# request so you don't need to restart to see changes
if self.settings.get("debug"):
if getattr(RequestHandler, "_templates", None):
for loader in RequestHandler._templates.values():
loader.reset()
RequestHandler._static_hashes = {}
#＝＝＝＝ 执行RequestHandler的_execute方法 ＝＝＝＝
handler._execute(transforms, *args, **kwargs)
return handler
class Application(object):
def _get_host_handlers(self, request):
#将请求的host和handlers中的主机模型进行匹配
host = request.host.lower().split(':')[0]
for pattern, handlers in self.handlers:
if pattern.match(host):
return handlers
# Look for default host if not behind load balancer (for debugging)
if "X-Real-Ip" not in request.headers:
for pattern, handlers in self.handlers:
if pattern.match(self.default_host):
return handlers
return None
Application._get_host_handlers
class RequestHandler(object):
SUPPORTED_METHODS = ("GET", "HEAD", "POST", "DELETE", "PUT", "OPTIONS") def __init__(self, application, request, **kwargs):
self.application = application
self.request = request
self._headers_written = False
self._finished = False
self._auto_finish = True
self._transforms = None # will be set in _execute
#获取在application中设置的 ui_modules 和ui_method
self.ui = _O((n, self._ui_method(m)) for n, m in
application.ui_methods.iteritems())
self.ui["modules"] = _O((n, self._ui_module(n, m)) for n, m in
application.ui_modules.iteritems())
self.clear() #设置服务器、内容类型编码和连接
# Check since connection is not available in WSGI
#检查连接是否可用，应该是长短连接有关。
if hasattr(self.request, "connection"):
self.request.connection.stream.set_close_callback(self.on_connection_close)
self.initialize(**kwargs) def initialize(self):
pass def clear(self):
"""Resets all headers and content for this response."""
self._headers = {
"Server": "TornadoServer/%s" % tornado.version,
"Content-Type": "text/html; charset=UTF-8",
}
if not self.request.supports_http_1_1():
if self.request.headers.get("Connection") == "Keep-Alive":
self.set_header("Connection", "Keep-Alive")
self._write_buffer = []
self._status_code = 200
RequestHandler.__init__
上述过程中，首先根据请求的URL去路由规则中匹配，一旦匹配成功，则创建路由相对应的handler的实例。例如：如果请求 的url是【/index/11】则会创建IndexHandler实例，然后再执行该对象的 _execute 方法。由于所有的 xxxHandler 类是RequestHandler的派生类，所以会默认执行 RequestHandler的 _execute 方法。
3.10 RequestHandler的_execute方法 （含有3.11、3.12、3.13）
此处代码主要有三项任务：
- 扩展点，因为self.prepare默认是空方法，所有可以在这里被重写
- 通过反射执行Handler的get/post/put/delete等方法
- 完成请求处理后，执行finish方法
class RequestHandler(object):
def _execute(self, transforms, *args, **kwargs):
"""Executes this request with the given output transforms."""
self._transforms = transforms
with stack_context.ExceptionStackContext(
self._stack_context_handle_exception):
if self.request.method not in self.SUPPORTED_METHODS:
raise HTTPError(405)
# If XSRF cookies are turned on, reject form submissions without
# the proper cookie
if self.request.method not in ("GET", "HEAD") and \
self.application.settings.get("xsrf_cookies"):
self.check_xsrf_cookie()
self.prepare()
if not self._finished:
#通过反射的方法，执行 RequestHandler 派生类的的 get、post、put方法
getattr(self, self.request.method.lower())(*args, **kwargs)
if self._auto_finish and not self._finished:
self.finish()
例：用户发送get请求
class MyHandler(tornado.web.RequestHandler):
def get(self):
self.write("Hello, world")
MyHandler.get
class RequestHandler(object):
def write(self, chunk):
assert not self._finished
if isinstance(chunk, dict):
chunk = escape.json_encode(chunk)
self.set_header("Content-Type", "text/javascript; charset=UTF-8")
chunk = _utf8(chunk)
self._write_buffer.append(chunk)
RequestHandler.write
上述在执行RequestHandler的write方法时，将数据保存在Handler对象的 _write_buffer 列表中，在之后执行finish时再讲数据写到IOStream对象的_write_buffer字段中，其类型是双向队列collections.deque()。
3.14、执行RequestHandler的finish
此段代码主要有两项任务：
- 将用户处理请求后返回的数据通过执行flush()方法发送到IOStream的_write_buffer队列中
- 纪录操作日志
class RequestHandler(object):
def finish(self, chunk=None):
"""Finishes this response, ending the HTTP request."""
if self._finished:
raise RuntimeError("finish() called twice") if chunk is not None:
self.write(chunk)
.
if not self._headers_written:
if (self._status_code == 200 and
self.request.method in ("GET", "HEAD") and
"Etag" not in self._headers):
self.set_etag_header()
if self.check_etag_header():
self._write_buffer = []
self.set_status(304)
if self._status_code == 304:
assert not self._write_buffer, "Cannot send body with 304"
self._clear_headers_for_304()
elif "Content-Length" not in self._headers:
content_length = sum(len(part) for part in self._write_buffer)
self.set_header("Content-Length", content_length) if hasattr(self.request, "connection"):
self.request.connection.set_close_callback(None) ＃执行flush方法，将处理请求返回的数据发送到IOStream的_write_buffer队列中
self.flush(include_footers=True)
self.request.finish()
＃纪录日志
self._log()
self._finished = True
self.on_finish() self.ui = None
3.15、执行RequestHandler的flush方法
此处代码主要有一项任务：
- 将处理请求返回的数据发送到IOStream的_write_buffer队列中
class RequestHandler(object):
def flush(self, include_footers=False, callback=None): chunk = b"".join(self._write_buffer)
self._write_buffer = []
if not self._headers_written:
self._headers_written = True
for transform in self._transforms:
self._status_code, self._headers, chunk = \
transform.transform_first_chunk(
self._status_code, self._headers,
chunk, include_footers)
# Ignore the chunk and only write the headers for HEAD requests
if self.request.method == "HEAD":
chunk = None # is sent).
if hasattr(self, "_new_cookie"):
for cookie in self._new_cookie.values():
self.add_header("Set-Cookie", cookie.OutputString(None)) start_line = httputil.ResponseStartLine('',
self._status_code,
self._reason)
# 执行HTTP1Connection下的write——headers方法
return self.request.connection.write_headers(
start_line, self._headers, chunk, callback=callback)
else:
for transform in self._transforms:
chunk = transform.transform_chunk(chunk, include_footers) # Ignore the chunk and only write the headers for HEAD requests
if self.request.method != "HEAD":
# 执行HTTP1Connection下的write方法
return self.request.connection.write(chunk, callback=callback)
else:
future = Future()
future.set_result(None)
return future
RequestHandler.flush()
class HTTP1Connection(httputil.HTTPConnection):
def write_headers(self, start_line, headers, chunk=None, callback=None):
else:
if callback is not None:
self._write_callback = stack_context.wrap(callback)
else:
future = self._write_future = Future()
data = b"\r\n".join(lines) + b"\r\n\r\n"
if chunk:
data += self._format_chunk(chunk)
self._pending_write = self.stream.write(data)
self._pending_write.add_done_callback(self._on_write_complete)
return future def write(self, chunk, callback=None):
else:
if callback is not None:
self._write_callback = stack_context.wrap(callback)
else:
future = self._write_future = Future()
self._pending_write = self.stream.write(self._format_chunk(chunk))
self._pending_write.add_done_callback(self._on_write_complete)
return future
HTTP1Connection
class BaseIOStream(object):
def write(self, data, callback=None): if data:
for i in range(0, len(data), WRITE_BUFFER_CHUNK_SIZE):
#将数据保存到collections.deque()类型的双向队列中_write_buffer中
self._write_buffer.append(data[i:i + WRITE_BUFFER_CHUNK_SIZE])
if callback is not None: self._write_callback = stack_context.wrap(callback)
if not self._connecting:
self._handle_write()
if self._write_buffer:
self._add_io_state(self.io_loop.WRITE)
BaseIOStream
以上代码执行完成之后，请求的处理基本上就完成了。下面就是等待监听客户端socket句柄的epoll触发，然后执行IOStream的_handle_event方法来将 响应数据发送给客户端。
3.20、执行RequestHandler的_log方法
此处代码主要有一项任务：
- 记录操作日志（利用logging模块）
class RequestHandler：
def _log(self): self.application.log_request(self)
class Application：
def log_request(self, handler):
if "log_function" in self.settings:
self.settings["log_function"](handler)
return
if handler.get_status() < 400:
log_method = logging.info
elif handler.get_status() < 500:
log_method = logging.warning
else:
log_method = logging.error
request_time = 1000.0 * handler.request.request_time()
log_method("%d %s %.2fms", handler.get_status(),
handler._request_summary(), request_time)
Application.log_request
3.21、IOStream的Handle_event方法
由于epoll中不但监听了服务器socket句柄还监听了客户端sokcet句柄，所以当客户端socket对象变化时，就会去调用之前指定的IOStream的_handler_events方法。
此段代码主要有一项任务：
- 将处理之后的响应数据发送给客户端
class BaseIOStream(object):
def _handle_events(self, fd, events):
try:
if self._connecting:
self._handle_connect()
if self.closed():
return
if events & self.io_loop.READ:
self._handle_read()
if self.closed():
return
if events & self.io_loop.WRITE:
#执行_handle_write方法，内部调用socket.send将数据响应给客户端
self._handle_write()
if self.closed():
return
if events & self.io_loop.ERROR:
self.error = self.get_fd_error()
IOStream._handle_events
3.22、IOStream的_handle_write方法
此段代码主要有两项任务：
- 调用socket.send给客户端发送响应数据
- 执行回调函数HTTPConnection的_on_write_complete方法
class BaseIOStream(object):
def _handle_write(self):
while self._write_buffer:
try:
if not self._write_buffer_frozen:
_merge_prefix(self._write_buffer, 128 * 1024)
#write_to_fd()内部调用客户端socket对象的send方法发送数据
num_bytes = self.write_to_fd(self._write_buffer[0]) if not self._write_buffer:
if self._write_callback:
callback = self._write_callback
self._write_callback = None
#执行回调函数关闭客户端socket连接（HTTPConnection的_on_write_complete方法）
self._run_callback(callback)
class IOStream(object):
def _run_callback(self, callback, *args, **kwargs):
try:
with stack_context.NullContext():
callback(*args, **kwargs)
except:
logging.error("Uncaught exception, closing connection.",
exc_info=True)
self.close()
raise
IOStream._run_callback
注：IOStream的_run_callback方法内部调用了HTTPConnection的_on_write_complete方法
3.23、执行HTTPConnection的_on_write_complete方法
此处代码主要有一项任务：
- 更新客户端socket所在epoll中的状态为【READ】，以便之后执行3.24时关闭socket客户端。
class HTTPConnection(object):
def _on_write_complete(self):
if self._request_finished:
self._finish_request()
def _finish_request(self):
if self.no_keep_alive:
disconnect = True
else:
connection_header = self._request.headers.get("Connection")
if self._request.supports_http_1_1():
disconnect = connection_header == "close"
elif ("Content-Length" in self._request.headers
or self._request.method in ("HEAD", "GET")):
disconnect = connection_header != "Keep-Alive"
else:
disconnect = True
self._request = None
self._request_finished = False
if disconnect:
self.stream.close()
return
self.stream.read_until("\r\n\r\n", self._header_callback)
HTTP1Connection
class IOStream(object):
def read_until(self, delimiter, callback):
"""Call callback when we read the given delimiter."""
assert not self._read_callback, "Already reading"
self._read_delimiter = delimiter
self._read_callback = stack_context.wrap(callback)
while True:
# See if we've already got the data from a previous read
if self._read_from_buffer():
return
self._check_closed()
if self._read_to_buffer() == 0:
break
#更新为READ
self._add_io_state(self.io_loop.READ)
IOStream.read_until
class IOStream(object):
def _add_io_state(self, state):
if self.socket is None:
# connection has been closed, so there can be no future events
return
if not self._state & state:
self._state = self._state | state
#执行IOLoop对象的update_handler方法
self.io_loop.update_handler(self.socket.fileno(), self._state)
IOStream._add_io_state
class IOLoop(object):
def update_handler(self, fd, events):
"""Changes the events we listen for fd."""
#self._impl就是epoll对象
self._impl.modify(fd, events | self.ERROR)
IOLoop.update_handler
3.24、IOStream的_handle_write方法（含3.25、3.26）
此段代码主要有一项任务：
- 关闭客户端socket
class IOStream(object):
def _handle_events(self, fd, events):
if not self.socket:
logging.warning("Got events for closed stream %d", fd)
return
try:
#由于在 2.23 步骤中已经将epoll的状态更新为READ，所以这次会执行_handle_read方法
if events & self.io_loop.READ:
self._handle_read()
#执行完_handle_read后，客户端socket被关闭且置空，所有此处就会执行return
if not self.socket:
return
#===============================终止===========================
if events & self.io_loop.WRITE:
if self._connecting:
self._handle_connect()
self._handle_write()
if not self.socket:
return
if events & self.io_loop.ERROR:
self.close()
return
state = self.io_loop.ERROR
if self.reading():
state |= self.io_loop.READ
if self.writing():
state |= self.io_loop.WRITE
if state != self._state:
self._state = state
self.io_loop.update_handler(self.socket.fileno(), self._state)
except:
logging.error("Uncaught exception, closing connection.",
exc_info=True)
self.close()
raise
Tornado源码探寻(请求到来)的更多相关文章
- 第三篇：白话tornado源码之请求来了
上一篇<白话tornado源码之待请求阶段>中介绍了tornado框架在客户端请求之前所做的准备(下图1.2部分),本质上就是创建了一个socket服务端,并进行了IP和端口的绑定,但是未 ...
- Tornado源码探寻（准备阶段）
上一篇从一个简单的例子大致了解到Tornado框架的一个概述,同时也看清了web框架的本质. 接下来,我们从tornado程序的起始来分析其源码: 一.概述 上图是摘自朋友的博客里的内容,这张图很明确 ...
- Tornado源码探寻(开篇)
一.先从一个简单的socket说起 运行脚本并在浏览器上访问http://127.0.0.1:8080 #!/usr/bin/env python #coding:utf-8 import socke ...
- 第五篇：白话tornado源码之褪去模板的外衣
上一篇<白话tornado源码之请求来了>介绍了客户端请求在tornado框架中的生命周期,其本质就是利用epoll和socket来获取并处理请求.在上一篇的内容中,我们只是给客户端返回了 ...
- 第二篇：白话tornado源码之待请求阶段
上篇<白话tornado源码之一个脚本引发的血案>用上帝视角多整个框架做了一个概述,同时也看清了web框架的的本质,下面我们从tornado程序的起始来分析其源码. 概述 上图是torna ...
- 04: 打开tornado源码剖析处理过程
目录:Tornado其他篇 01: tornado基础篇 02: tornado进阶篇 03: 自定义异步非阻塞tornado框架 04: 打开tornado源码剖析处理过程 目录: 1.1 torn ...
- Tornado源码分析系列之一: 化异步为'同步'的Future和gen.coroutine
转自:http://blog.nathon.wang/2015/06/24/tornado-source-insight-01-gen/ 用Tornado也有一段时间,Tornado的文档还是比较匮乏 ...
- Tornado源码分析 --- 静态文件处理模块
每个web框架都会有对静态文件的处理支持,下面对于Tornado的静态文件的处理模块的源码进行分析,以加强自己对静态文件处理的理解. 先从Tornado的主要模块 web.py 入手,可以看到在App ...
- Python框架之Tornado (源码之褪去模板外衣)
上一篇介绍了客户端请求在tornado框架中的生命周期,其本质就是利用epoll和socket来获取并处理请求.在上一篇的内容中,我们只是给客户端返回了简单的字符串,如:“Hello World”,而 ...
随机推荐
- ubuntu sudo
sudo(substitute user 或者 superuser do),是一种程序, 以允许用户通过安全的方式使用特殊的权限运行程序(通常为系统的超级 用户) 语法 sudo [-bhHpV][- ...
- JavaScript学习总结【12】、JS AJAX应用
1.AJAX 简介 AJAX(音译为:阿贾克斯) = Asynchronous JavaScript and XML(异步的 JavaScript 和 XML),是指一种创建交互式网页应用的网页开发技 ...
- 青瓷qici - H5小游戏 抽奖机 0 创建工程
安装运行平台需要nodejs,具体方法请参照官方说明文档. 运行后打开了一个空空的窗口. 首先我们进行工程设置,菜单>工程>设置 菜单里面设置我们游戏的名称,到时候会显示在游戏的title ...
- lamp环境－编译安装
http://my.oschina.net/JerryBaby/blog/292731 http://blog.chinaunix.net/uid-20639775-id-154442.html ht ...
- node开子线程模块--tagg2
tagg2包同样具有tagg包的多线程功能,采用新的node-gyp命令进行编译,同时它跨平台支持,mac,linux,windows下都可以使用,对开发人员的api也更加友好.安装方法很简单,直接n ...
- 如何利用C生成.so供Mono调用
Mono诞生的初衷是为了吸引更多的Windows .Net程序员来加入Linux平台的开发.但在Linux世界中C语言依然是 主流.很多时候一些关键应用(比如大型 笛卡儿 乘积运算.需要调用平台硬件功 ...
- Html DOM 常用属性和方法
Node对象的节点类型***************************************************接口 nodeType常量 nodeType值 备注Element Node ...
- bzoj 3823: 定情信物 线性筛逆元
3823: 定情信物 Time Limit: 10 Sec Memory Limit: 128 MBSubmit: 108 Solved: 2[Submit][Status] Descriptio ...
- 网页增重不可控？试试 OneAPM Cloud Test
再次发生了!HTTP Archive 报告在收集了 50 万个最受欢迎的网站的技术信息,经过整理分析后指出:2015 年,网页的平均「体重」增加了 16%,达到了 2,262 KB,近似于 2014 ...
- AQuery简介：jQuery for Android
jQuery的流行已经成为了事实,它极大地减少了执行异步任务和操作DOM所需要的代码数量.新项目AQuery想要为Android开发者提供同样的功能.为了向你展示Android Query能够够为用户 ...