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问题:
I have a very simple web sever written in Python. It listens on port 13000, how can I make it deliver a simple "Hello World" webpage if http://localhost:13000 is opened in browser?
Right there is my code:
# set up socket and connection
while True:
sock, addr = servSock.accept()
# WHAT GOES HERE?
sock.close()
As you can see, I am not exactly sure how to actually send back the webpage?
I only have to use the socket library.
EDIT: The problem is not that I don't know how to formulate the HTTP response, I don't know how to actually make it display in my browser! It just keeps spinning/loading.
回答1:
Updated according to question change
Possibly, it keeps spinning because in combination of absense of Content-Length and Connection headers, browser may assume it's Connection: keep-alive, so it continues to receive data from your server forever. Try to send Connection: close, and pass actual Content-Length to see if that helps.
Won't this do what you expect it to? :)
#!/usr/bin/env python
# coding: utf8
import socket
MAX_PACKET = 32768
def recv_all(sock):
r'''Receive everything from `sock`, until timeout occurs, meaning sender
is exhausted, return result as string.'''
# dirty hack to simplify this stuff - you should really use zero timeout,
# deal with async socket and implement finite automata to handle incoming data
prev_timeout = sock.gettimeout()
try:
sock.settimeout(0.01)
rdata = []
while True:
try:
rdata.append(sock.recv(MAX_PACKET))
except socket.timeout:
return ''.join(rdata)
# unreachable
finally:
sock.settimeout(prev_timeout)
def normalize_line_endings(s):
r'''Convert string containing various line endings like \n, \r or \r\n,
to uniform \n.'''
return ''.join((line + '\n') for line in s.splitlines())
def run():
r'''Main loop'''
# Create TCP socket listening on 10000 port for all connections,
# with connection queue of length 1
server_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM, \
socket.IPPROTO_TCP)
server_sock.bind(('0.0.0.0', 13000))
server_sock.listen(1)
while True:
# accept connection
client_sock, client_addr = server_sock.accept()
# headers and body are divided with \n\n (or \r\n\r\n - that's why we
# normalize endings). In real application usage, you should handle
# all variations of line endings not to screw request body
request = normalize_line_endings(recv_all(client_sock)) # hack again
request_head, request_body = request.split('\n\n', 1)
# first line is request headline, and others are headers
request_head = request_head.splitlines()
request_headline = request_head[0]
# headers have their name up to first ': '. In real world uses, they
# could duplicate, and dict drops duplicates by default, so
# be aware of this.
request_headers = dict(x.split(': ', 1) for x in request_head[1:])
# headline has form of "POST /can/i/haz/requests HTTP/1.0"
request_method, request_uri, request_proto = request_headline.split(' ', 3)
response_body = [
'<html><body><h1>Hello, world!</h1>',
'<p>This page is in location %(request_uri)r, was requested ' % locals(),
'using %(request_method)r, and with %(request_proto)r.</p>' % locals(),
'<p>Request body is %(request_body)r</p>' % locals(),
'<p>Actual set of headers received:</p>',
'<ul>',
]
for request_header_name, request_header_value in request_headers.iteritems():
response_body.append('<li><b>%r</b> == %r</li>' % (request_header_name, \
request_header_value))
response_body.append('</ul></body></html>')
response_body_raw = ''.join(response_body)
# Clearly state that connection will be closed after this response,
# and specify length of response body
response_headers = {
'Content-Type': 'text/html; encoding=utf8',
'Content-Length': len(response_body_raw),
'Connection': 'close',
}
response_headers_raw = ''.join('%s: %s\n' % (k, v) for k, v in \
response_headers.iteritems())
# Reply as HTTP/1.1 server, saying "HTTP OK" (code 200).
response_proto = 'HTTP/1.1'
response_status = '200'
response_status_text = 'OK' # this can be random
# sending all this stuff
client_sock.send('%s %s %s' % (response_proto, response_status, \
response_status_text))
client_sock.send(response_headers_raw)
client_sock.send('\n') # to separate headers from body
client_sock.send(response_body_raw)
# and closing connection, as we stated before
client_sock.close()
run()
For more detailed description, please see description of HTTP protocol.
回答2:
Send back something like:
HTTP/1.1 200 OK
Date: Wed, 11 Apr 2012 21:29:04 GMT
Server: Python/6.6.6 (custom)
Content-Type: text/html
Then the actual html code. Make sure there is a newline after the Content-Type line and before the html.
回答3:
# set up socket and connection
while True:
sock, addr = servSock.accept()
sock.send("HTTP/1.1 200 OK\n"
+"Content-Type: text/html\n"
+"\n" # Important!
+"<html><body>Hello World</body></html>\n");
sock.close()
回答4:
or, if you just don't want to remember the full protocol, you can find it again using :
% nc stackoverflow.com 80
GET / HTTP/1.1
Host: stackoverflow.com
HTTP/1.1 200 OK
Cache-Control: public, max-age=60
Content-Type: text/html; charset=utf-8
Expires: Wed, 11 Apr 2012 21:33:49 GMT
Last-Modified: Wed, 11 Apr 2012 21:32:49 GMT
Vary: *
Date: Wed, 11 Apr 2012 21:32:49 GMT
Content-Length: 206008
[...]
%
well, you shall usually prefer a site that is less verbose (usually serving only a static file) than stackoverflow ;)
The minimal requirements (you'll find on the answer) is :
sock.send(r'''HTTP/1.0 200 OK
Content-Type: text/plain
Hello, world!
''')
two returns are mandatory for the server to get the answer, otherwise the browser waits indefinitely for headers
But to mimic the behaviour of a webserver, don't forget to send your answer only after the browser sends you some data followed by two carriage returns, usually you can get what it sends using :
% nc -kl localhost 13000
GET / HTTP/1.1
Host: localhost:13000
User-Agent: Mozilla/5.0...
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip, deflate
DNT: 1
Connection: keep-alive
%
so you can improve your test routines
回答5:
I took a previous answer and edited the code for Python3 utf-8 and bytes encoding. Thanks for the original answer it helped out a lot.
import socket
MAX_PACKET = 32768
def recv_all(sock):
r'''Receive everything from `sock`, until timeout occurs, meaning sender
is exhausted, return result as string.'''
# dirty hack to simplify this stuff - you should really use zero timeout,
# deal with async socket and implement finite automata to handle incoming data
prev_timeout = sock.gettimeout()
try:
sock.settimeout(0.1)
rdata = []
while True:
try:
# Gotta watch for the bytes and utf-8 encoding in Py3
rdata.append(sock.recv(MAX_PACKET).decode('utf-8'))
except socket.timeout:
return ''.join(rdata)
# unreachable
finally:
sock.settimeout(prev_timeout)
def normalize_line_endings(s):
r'''Convert string containing various line endings like \n, \r or \r\n,
to uniform \n.'''
test = s.splitlines()
return ''.join((line + '\n') for line in s.splitlines())
def run():
r'''Main loop'''
# Create TCP socket listening on 10000 port for all connections,
# with connection queue of length 1
server_sock = socket.socket(socket.AF_INET,
socket.SOCK_STREAM,
socket.IPPROTO_TCP)
#Added the port 13001 for debuging purposes
try:
server_sock.bind(('0.0.0.0', 13000))
print('PORT 13000')
except:
server_sock.bind(('0.0.0.0', 13001))
print('PORT 13001')
# except:
# server_sock.bind(('0.0.0.0', 13002))
# print('PORT 13002')
server_sock.listen(1)
while True:
# accept connection
try:
client_sock, client_addr = server_sock.accept()
# headers and body are divided with \n\n (or \r\n\r\n - that's why we
# normalize endings). In real application usage, you should handle
# all variations of line endings not to screw request body
request = normalize_line_endings(recv_all(client_sock)) # hack again
request_head, request_body = request.split('\n\n', 1)
# first line is request headline, and others are headers
request_head = request_head.splitlines()
request_headline = request_head[0]
# headers have their name up to first ': '. In real world uses, they
# could duplicate, and dict drops duplicates by default, so
# be aware of this.
request_headers = dict(x.split(': ', 1) for x in request_head[1:])
# headline has form of "POST /can/i/haz/requests HTTP/1.0"
request_method, request_uri, request_proto = request_headline.split(' ', 3)
response_body = [
'<html><body><h1 style="color:red">Hello, world!</h1>',
'<p>This page is in location %(request_uri)r, was requested ' % locals(),
'using %(request_method)r, and with %(request_proto)r.</p>' % locals(),
'<p>Request body is %(request_body)r</p>' % locals(),
'<p>Actual set of headers received:</p>',
'<ul>',
]
for request_header_name, request_header_value in request_headers.items():
response_body.append('<li><b>%r</b> == %r</li>' % (request_header_name,
request_header_value))
response_body.append('</ul></body></html>')
response_body_raw = ''.join(response_body)
# Clearly state that connection will be closed after this response,
# and specify length of response body
response_headers = {
'Content-Type': 'text/html; encoding=utf8',
'Content-Length': len(response_body_raw),
'Connection': 'close',
}
response_headers_raw = ''.join('%s: %s\n' % (k, v) for k, v in \
response_headers.items())
# Reply as HTTP/1.1 server, saying "HTTP OK" (code 200).
response_proto = 'HTTP/1.1'.encode()
response_status = '200'.encode()
response_status_text = 'OK'.encode() # this can be random
# sending all this stuff
client_sock.send(b'%s %s %s' % (response_proto, response_status,
response_status_text))
client_sock.send(response_headers_raw.encode())
client_sock.send(b'\n') # to separate headers from body
client_sock.send(response_body_raw.encode())
# and closing connection, as we stated before
finally:
client_sock.close()
run()
回答6:
You might want to Checkout web objects http://www.webob.org/
It's a simple lightweight project for creating http compatible requests and responses. You can do just about anything with you requests/response objects ... Or just delegate the heavy lifting to WebObjects
Sample
>>> from webob import Response
>>> res = Response()
>>> res.status
'200 OK'
>>> res.headerlist
[('Content-Type', 'text/html; charset=UTF-8'), ('Content-Length', '0')]
>>> res.body
''
