研究rfile如何解析消息头和消息正文，并返回结果的过程。
rfile和wfile 根据 client_socket 由HttpProtocal 类的setup函数生成。
生成流程，如下代码：
def server():
client_socket = sock.accept() pool.spawn_n(serv.process_request,client_socket)
def process_request(self,sock_params):
sock,address = sock_params proto.__init__(sock,address,self)
class BaseRequestHandler:
def __init__(self,request,client_address,server):
self.request = request
self.client_address = client_address
self.server = server
class HttpProtocol
def setup(self):
conn = self.connection = self.request
try:
self.rfile = conn.makefile('rb',self.rbufsize)
self.wfile = conn.makefile('wb',self.wbufsize)
except (AttributeError,NotImplementedError):
if hasattr(conn,'send') and hasattr(conn,'recv'):
# it's an SSL.Connection
self.rfile = socket._fileobject(conn,"rb",self.rbufsize)
self.wfile = socket._fileobject(conn,"wb",self.wbufsize)
其中sock 由 eventlet 所重写的listen函数生成，基于eventlet.greenio模块的GreenSocket 类。
self.connection调用makefile创建一个与该套接字相关连的文件
通过调试 self.rfile.readline函数(位于socket模块)，可以判断python对于http的协议主要是根据数据中的/r/n分隔符，区分开消息头和消息正文,且消息正文长度由content-length消息头决定.
客户端发送数据：
POST /oauth/access_token HTTP/1.1
User-Agent: curl/7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7
NSS/3.14.0.0 zlib/1.2.3 libidn/1.18 libssh2/1.4.2
Host: localhost
Accept: /
Content-Length: 51
Content-Type: application/x-www-form-urlencoded
函数入下：
def readline(self,size=-1):
buf = self._rbuf
buf.seek(0,2) # seek end
if buf.tell() > 0:
# check if we already have it in our buffer
buf.seek(0)
bline = buf.readline(size)
if bline.endswith('\n') or len(bline) == size:
self._rbuf = StringIO()
self._rbuf.write(buf.read())
return bline
del bline
if size < 0:
# Read until \n or EOF,whichever comes first
if self._rbufsize <= 1:
# Speed up unbuffered case
buf.seek(0)
buffers = [buf.read()]
self._rbuf = StringIO()
data = None
recv = self._sock.recv
while True:
try:
while data != "\n":
data = recv(1)
if not data:
break
buffers.append(data)
except error,e:
# The try..except to catch EINTR was moved outside the
# recv loop to avoid the per byte overhead.
if _exception_was_EINTR(e):
continue
raise
break
return "".join(buffers)
buf.seek(0,2) # seek end
self._rbuf = StringIO() # reset _rbuf. we consume it via buf.
while True:
try:
data = self._sock.recv(self._rbufsize)
except error,e:
if _exception_was_EINTR(e):
continue
raise
if not data:
break
nl = data.find('\n')
if nl >= 0:
nl += 1
buf.write(data[:nl])
self._rbuf.write(data[nl:])
del data
break
buf.write(data)
return buf.getvalue()
else:
# Read until size bytes or \n or EOF seen,whichever comes first
buf.seek(0,2) # seek end
buf_len = buf.tell()
if buf_len >= size:
buf.seek(0)
rv = buf.read(size)
self._rbuf = StringIO()
self._rbuf.write(buf.read())
return rv
self._rbuf = StringIO() # reset _rbuf. we consume it via buf.
while True:
try:
data = self._sock.recv(self._rbufsize)
except error,e:
if _exception_was_EINTR(e):
continue
raise
if not data:
break
left = size - buf_len
# did we just receive a newline?
nl = data.find('\n',left)
if nl >= 0:
nl += 1
# save the excess data to _rbuf
self._rbuf.write(data[nl:])
if buf_len:
buf.write(data[:nl])
break
else:
# Shortcut. Avoid data copy through buf when
# returning
# a substring of our first recv().
return data[:nl]
n = len(data)
if n == size and not buf_len:
# Shortcut. Avoid data copy through buf when
# returning exactly all of our first recv().
return data
if n >= left:
buf.write(data[:left])
self._rbuf.write(data[left:])
break
buf.write(data)
buf_len += n
#assert buf_len == buf.tell()
return buf.getvalue()
注：如果消息正文transfer-encoding:chunked 方式传输，则不实用上述解析方式。
最终消息头数据存储在self.environ变量中，消息正文由env[‘eventlet.input’]保存。
其中env[‘eventlet.input’] 的创建方式如下
env[‘wsgi.input’] =Input(self.rfile,length,\
wfile=wfile,wfile_line=wfile_line,chunked_input=chunked)
若self.rfile 所读取的数据为”,则表明收到客户端答复，释放网络资源。