I can't seem to figure out why my code can't handle the exception of reporting an error if my web server does not contain a file. In the directory of my server I have the code for it and HelloWorld.html. For other files it should report an error. I'm looking through my code and it would seem that it is reading any file and just saying that its contents are blank without actually throwing an error that the file is not on the server. What is going on here?
#Tasks: Create a socket, bind to a specific address and port, send and receive an HTTP packet.
#Description: Web server should handle one HTTP request at a time. So the serve closes its TCP connection after response.
#Accept and parse the HTTP request, get the requested file from the server (i.e. HelloWorld.html), create a response
#message with the requested file and header lines, then send the response to the client.
#Error handling: If file not found then send HTTP "404 Not Found" Message back to client.
#import socket module: here we are using a low-level networking class from Python
from socket import *
#create the socket that belongs to the server.
#AF_INTET represents the address families and protocols.
#SOCK_STREAM represents the socket type
serverSocket = socket(AF_INET, SOCK_STREAM)
#Prepare a server socket
#Define variable for serverPort; we'll use the one in the helper page of the book
serverPort = 51350
#Define host address
serverHost = ''
#Bind the socket to the local host machine address and port
serverSocket.bind((serverHost, serverPort))
#Listen for TCP connections from the client
serverSocket.listen(1)
#Verify setup for receiving
print 'Server is ready to receive'
while True:
#Establish the connection
print 'Ready to serve...'
#When the server receive a request from the client it must establish a new connectionSocket and begin taking in the data.
connectionSocket, addr = serverSocket.accept()
try:
#Take data from connectionSocket and place in message.
#.recvfrom doesn't work because it expects data and return address variables.
message = connectionSocket.recv(1024)
#uncomment for header information
#print message
#parse the message
filename = message.split()[1]
f = open(filename[1:])
outputdata = f.read();
#Send one HTTP header line into socket
connectionSocket.send('HTTP/1.1 200 OK\r\n\r\n')
#Send the content of the requested file to the client
for i in range(0, len(outputdata)):
connectionSocket.send(outputdata[i])
connectionSocket.close()
except IOError:
#Send response message for file not found
connectionSocket.send('404 Not Found')
connectionSocket.close()
#Close client socket
serverSocket.close()
Perhaps you need "HTTP/1.1 404 Not Found\r\n\r\n" instead of "404 Not Found".
Also, you seem to close serverSocket within the loop, thus next accept() fails.
Related
I am writing a very simple Python socket program to read an HTML body from the server. If I create a HelloWorld.html file and open it with the designated host and port, I can open the file in my browser with the following server and read the message in the HTML file. However, I am having trouble reading in the same information from my client.
Server
from socket import *
serverSocket = socket(AF_INET,SOCK_STREAM)
host = '127.0.0.1'
port = 6789
serverSocket.bind((host,port))
serverSocket.listen(5)
print("server started...")
(connectionSocket, addr) = serverSocket.accept()
try:
message = connectionSocket.recv(1024).decode()
filename = message.split()[1]
f = open(filename[1:]) # Throws IOError if file not found
print(filename, "found")
connectionSocket.send("HTTP/1.0 200 OK\r\n".encode())
connectionSocket.send("Content-Type: text/html\r\n".encode())
connectionSocket.send(message.encode())
outputdata = f.read()
for i in range(0, len(outputdata)):
connectionSocket.send(outputdata[i].encode())
connectionSocket.send("\r\n".encode())
connectionSocket.close()
print(filename, "delivered")
except IOError:
print(filename, "NOT found")
connectionSocket.send('HTTP/1.0 404 NOT FOUND\r\n')
connectionSocket.close()
print("file not found message delivered")
serverSocket.close()
print("server closed...")
My server seems to be working. However, when my client tries to send the HTML object path to the socket and have the server read it, it does not seem to be picking up the message. I have just started socket programming in Python and I am trying to understand how the server receives the message from the socket. My initial thought was if I send the path of the HTML object (located in same directory as client and server) to the socket, the server should be able to read that information, open it, and return the information to the client.
Client
from socket import *
import sys
client = socket(AF_INET, SOCK_STREAM)
host = sys.argv[1]
port = sys.argv[2]
obj = sys.argv[3]
port = int(port)
client.connect((host, port))
print(client.getsockname())
request = obj
client.send("hello".encode())
client.send(request.encode())
s = client.recv(1024).decode()
print(s)
For my client, I accept the host,port, and the path to the HTML from a commandline argument and establish a connection.
When I run the browser for my HTML file with the url http://127.0.0.1:6789/HelloWorld.html, the server responds well. However, when I run the server and run the client with the command py capClient.py 127.0.0.1 6789 HelloWorld.html on the shell, it returns the filename = message.split()[1] IndexError: list index out of range error. I am assuming that this problem is coming from the server not being able to split the message coming in from the connectionSocket as an acceptable HTML object path.
What are some tips on modifying the client code to receive HTML file from servers?
This trouble is because you await message string is 'hello HelloWorld.html', but it is 'helloHelloWorld.html' and split() get you list ['helloHelloWorld.html'] where index 1 not exists.
f = open(filename[1:])
# must be replaced with [1:] give you a list, not string
f = open(filename)
# there needs encode()
connectionSocket.send('HTTP/1.0 404 NOT FOUND\r\n'.encode())
Im having trouble getting my very basic and simple TCP Server to properly work with http requests. This is what I have so far
from socket import *
import sys
serverSocket = socket(AF_INET, SOCK_STREAM)
serverSocket.bind(('', 4567))
serverSocket.listen(1)
while True:
print('Ready to serve...')
connectionSocket, addr = serverSocket.accept()
print("connected from: ", addr)
try:
message = connectionSocket.recv(1024)
filename = message.split()[1]
f = open(filename[1:])
outputdata = f.read()
connectionSocket.send("HTTP/1.1 200 OK\r\n")
for i in range(0, len(outputdata)):
connectionSocket.send(outputdata[i].encode())
connectionSocket.send("\r\n".encode())
connectionSocket.close()
except IOError:
connectionSocket.send("file not found")
serverSocket.close()
sys.exit()
The error comes from the open statement. I dont fully understand how this line of code's return value is organized.
message = connectionSocket.recv(1024)
I know that the return value is in bytes but when I try to use a fuction to turn it into a string like decode() i get errors as well
I have the .py file and the html file sitting in the same directory on my local machine and the way I test this is I just run this and open up a browser and type in
http://127.0.0.1:4567/helloworld.html
My code then promptly crashes after receiving the HTTP request.
Any and all help will be greatly appreciated!
There are numerous problems with your code and since you don't state what specific issues you are concerned about, here is what I see:
connectionSocket.send(outputdata[i].encode())
connectionSocket.send("\r\n".encode())
That appears to send a newline after every character you send back to the client.
Also, it doesn't deal with the client disconnecting because you're sending back invalid data.
Even if what you were trying to do didn't have these errors in it, you don't appear to be attempting to send back a valid http response.
https://www.w3.org/Protocols/rfc2616/rfc2616-sec6.html
We're learning about sockets in Networking and we've been tasked to fill out a template in Python (teacher's using Python2.x while I'm using Python3.x).
# Import socket module
from socket import *
# Create a TCP server socket
#(AF_INET is used for IPv4 protocols)
#(SOCK_STREAM is used for TCP)
serverSocket = socket(AF_INET, SOCK_STREAM)
# Assign a port number
serverPort = 6789
# Bind the socket to server address and server port
serverSocket.bind(('',serverPort))
# Listen to at most 1 connection at a time
serverSocket.listen(1)
# Server should be up and running and listening to the incoming connections
while True:
print ("Ready to serve...")
# Set up a new connection from the client
connectionSocket, addr = serverSocket.accept()
# If an exception occurs during the execution of try clause
# the rest of the clause is skipped
# If the exception type matches the word after except
# the except clause is executed
try:
# Receive the request message from the client
message = connectionSocket.recv(4096).decode()
# Extract the path of the requested object from the message
# The path is the second part of HTTP header, identified by [1]
filename = message.split()[1]
# Because the extracted path of the HTTP request includes
# a character '\', we read the path from the second character
f = open(filename[1:])
# Store the entire contenet of the requested file in a temporary buffer
outputdata = f.read()
# Send the HTTP response header line to the connection socket
connectionSocket.send(("HTTP/1.1 200 OK \r\n").encode())
# Send the content of the requested file to the connection socket
for i in range(0, len(outputdata.encode())):
connectionSocket.send(outputdata.encode())
connectionSocket.send(("\r\n").encode())
# Close the client connection socket
connectionSocket.close()
break
except IOError:
# Send HTTP response message for file not found
connectionSocket.send(("HTTP/1.1 404 NOT FOUND\r\n").encode())
connectionSocket.send(("<html><head></head><body><h1>ERROR. TRY AGAIN</h1></body></html>\r\n").encode())
# Close the client connection socket
connectionSocket.close()
break
#Close the Socket
serverSocket.close()
The file I'm reading into it is a .htm file:
<html><head><title>HTML Test File</title></head><body><h1>Trying to Get This Frickin' Program to Work</h1></body></html>
When I run the program and enter: localhost:6789/TestFile.htm, it prints the file contents over and over and gives me the error message: line 34, indexerror: list index out of range. edit: break takes care of the error message, but file is still being printed over and over
What am I doing wrong?
edit #2: now I'm trying to do the error handling, but it merely states that no data was sent when I type in a file that doesn't exist (i.e. localhost:6789/Test.htm). How do I get the error message to print?
for i in range(0, len(outputdata.encode())):
connectionSocket.send(outputdata.encode())
This code:
encodes the text twice
loops 121 times (which is the length of the file you posted, encoded as ASCII or UTF-8)
sends the entire file each of the 121 times
I am using TCP sockets to communicate between my server and clients. The server code and socket code are as below:
server:
from socket import *
HOST = 'xx.xx.xx.xx'
PORT = 1999
serversocket = socket(AF_INET,SOCK_STREAM)
serversocket.bind((HOST,PORT))
print 'bind success'
serversocket.listen(5)
print 'listening'
while True:
(clientsocket, address) = serversocket.accept()
print ("Got client request from",address)
#clientsocket.send('True')
data = clientsocket.recv(1024)
print data
clientsocket.send('True')
clientsocket.close()
client:
import socket
import sys
# Create a TCP/IP socket
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# Connect the socket to the port on the server given by the caller
server_address = ('xx.xx.xx.xx', 1999)
print >>sys.stderr, 'connecting to %s port %s' % server_address
sock.connect(server_address)
try:
message = 'This is the message. It will be repeated.'
print >>sys.stderr, 'sending'
for x in range (0,1):
name=raw_input ('what is ur name')
print type(name)
sock.send(name)
print sock.recv(1024)
finally:
sock.close()
I am able to communicate with the server from client and able to send and receive data. But the problem I am facing is that I am not able to send and receive data continuously from the server. I have to restart my client code on my laptop to send and receive data again from the server. The way the above client code is working is that when I give a keyboard input, then the socket sends data to server and server responds back. But in the client code, in the for loop if I do two iterations, for the second iteration the data I enter from keyboard is not reaching server. I need to restart my client code to send data again. How do I fix this ?
Also, when once client is connected to the server, the other cannot connect to the server. Any ideas on how to do this ?
You need to design and implement a protocol that specifies what each side is supposed to do and then implement that protocol. You're expecting it to work by magic.
For example:
data = clientsocket.recv(1024)
I suspect you are expecting this to receive a "message". But TCP has no notion of messages. If you need to send and receive messages, you need to define precisely what a "message" is for your protocol and write code to send and receive them.
It may be helpful to look at the specifications for other protocols that use TCP such as HTTP, FTP, or IRC. It really is worth the time to write out a specification of your protocol before you write any code. It will save a lot of pain.
I am trying to connect to URL https://www.ssehl.co.uk/HALO/publicLogon.do in Python.
The simple solution using requests fails:
import requests
r = requests.get('https://www.ssehl.co.uk/HALO/publicLogon.do')
print r.text
with error
File "c:\Python27\lib\site-packages\requests\adapters.py", line 327, in send
raise ConnectionError(e)
requests.exceptions.ConnectionError: HTTPSConnectionPool(host='www.ssehl.co.uk', port=443): Max retries exceeded with url: /HALO/publicLogon.do (Caused by <class 'httplib.BadStatusLine'>: '')
so I tried to get the raw response from the server using library socket:
import socket #for sockets
import sys #for exit
#create an INET, STREAMing socket
try:
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
except socket.error:
print 'Failed to create socket'
sys.exit()
print 'Socket Created'
host = 'www.ssehl.co.uk';
port = 443;
try:
remote_ip = socket.gethostbyname(host)
except socket.gaierror:
#could not resolve
print 'Hostname could not be resolved. Exiting'
sys.exit()
#Connect to remote server
s.connect((remote_ip , port))
print 'Socket Connected to ' + host + ' on ip ' + remote_ip
#Send some data to remote server
message = "GET /HALO/publicLogon.do HTTP/1.1\r\n\r\n"
try :
#Set the whole string
s.sendall(message)
except socket.error:
#Send failed
print 'Send failed'
sys.exit()
print 'Message send successfully'
#Now receive data
reply = s.recv(4096)
print reply
will output:
Socket Created
Socket Connected to www.ssehl.co.uk on ip 161.12.7.194
Message send successfully
Reply:
after reply there is some garbage which I can't paste, however this is a sublime console screenshot:
Screenshot
Is there any way to get a 200 response from the server, just like a browser?
For some reason when you use either Python's built in stuff (urllib2, requests, httplib) or even command line stuff (curl, wget) over https the server spazzes out and gives an erroneous response.
However when you request the page over regular http, it works fine, for example:
import urllib2
print urllib2.urlopen('http://www.ssehl.co.uk/HALO/publicLogon.do').getcode()
prints out
>> 200
My guess is that their servers are configured wrong and your browser somehow deals with it silently.
It worked for me when I used port 80. Sooo:
port = 80;
There must be some error when using HTTPS servers thought Python...
Also, you are sending wrong request. You are not sending the hostname. Fixed request:
message = "GET /HALO/publicLogon.do HTTP/1.1\r\nHostname: %s\r\n\r\n"%host
So here is working code.
I think the problem exists, because port 443 is encrypted. And Python doesn't support encryption (probably).
You should use ssl.wrap_socket if you want support https.
See http://docs.python.org/2/library/ssl.html for details.