I have a python flask api running on my laptop. It starts with a localhost url. Base url is below:
http://localhost:5555/
I am trying to integrate this api with a c++ project but facing few issues with port number. Is it possible to remove the port number and make the base url like below
http://localhost/
Below is the code:
if __name__ == '__main__':
import os
HOST = os.environ.get('SERVER_HOST', 'localhost')
try:
PORT = int(os.environ.get('SERVER_PORT', '5555'))
except ValueError:
PORT = 5555
app.run(HOST, PORT)
If I do app.run(HOST) it still starts with port 5000. Is it not possible to remove port number from the url. Please help. Thanks
Browsers don't show port numbers when you're connecting to the default port for a given protocol (i.e., :80 for http, :443 for https). Running a Flask server on port 80 is doable, but depends on what Operating System you're running on. It's a convention on many operating systems to reserve "low" port numbers (those under 1024) for privileged software, so you'd need to arrange to run Flask in a privileged way.
But you note that the issue is integrating with a C++ project, which hints that you might have a different issue. If the problem you're running in to is that you're unable to make a request from C++ to a local Flask server on localhost:5000, then the issue may be that the HTTP request that the C++ program constructs must include the header Host: localhost:5000.
Related
I'm creating an extremely simple Vega visualization viewer: it's a one file module that serves a base HTML page containing just the Vega graphic and an HTML5 EventSource of updates. The user (me) is working in a Python shell through ssh, creates an object representing the viewer, which prints its IP and port for the user to paste into their (my) web browser. This HTTP server doesn't serve files or take input from clients, so I don't see any security concerns.
The part I'm unsure of is how to set (host, port) such that my web browser can find the HTTP server running in the remote Python. I've been experimenting all afternoon, and I don't know if I'm misunderstanding what's supposed to happen or if the servers I use have changed their access policies.
Here's a minimal example:
import SimpleHTTPServer
import SocketServer
Handler = SimpleHTTPServer.SimpleHTTPRequestHandler
httpd = SocketServer.TCPServer((host, port), Handler)
print(httpd.server_address)
httpd.serve_forever()
If I'm running this locally and want to ensure that outside viewers cannot access it, do I set host to "127.0.0.1" because that means a client would have to access it as 127.0.0.1, which can only happen locally? In this case, port can be 0 to get any open port.
If I'm running this remotely want to to ensure that outside viewers can access it, do I set host to "" or "0.0.0.0" because that means that a client can access it as any address that makes its way to the server? In this case, I might not be able to set port to 0 because many of those ports might be blocked, or is the OS smarter about this?
Basically, how is access control in Python's SocketServer supposed to work?
This is basic TCP. Nothing to do with Python.
If you listen at 127.0.0.1, only clients running in the same host can connect.
If you listen at 0.0.0.0, anybody can connect, firewalls permitting.
I have a server running by using python's base http server. The host name used is '127.0.0.1' the local host, and the port number is set to 8000. I have the public ip address of the computer operating this server.
If I wanted to send a http get request to this from another computer, what would I type into my browser?
Sounds like you've got your server process running on the wrong interface. 127.0.0.1 is not a hostname but an IP address, specifically the local loopback address. It is not reachable from any other machine (unless something's gone tragically wrong with your network configuration).
You can run anything you like on the 127.0.0.1 interface, and no one else can directly connect to it from a remote machine. That's pretty much the point --- it's for testing programs that use the Internet Protocol, and (in recent years) for starting single-user servers without worrying about security. (Python 2's SimpleHTTPServer does this, as do some personal wikis, and I think iPython Notebook.)
The public address for the host running your Web server is a completely unrelated network interface, with its own hardware and its own port 8000. It doesn't know or care that you've got something listening on some other interface's port 8000, so it should refuse attempts to connect to that port.
Since you didn't post any code, I have no idea what you need to change to get your server running on the correct interface. Assuming you've more or less followed the example in the BaseHTTPServer.HTTPServer docs:
def run(
server_class=BaseHTTPServer.HTTPServer,
handler_class=BaseHTTPServer.BaseHTTPRequestHandler,
):
server_address = ('', 8000) # <----= Replace the string.
httpd = server_class(server_address, handler_class)
httpd.serve_forever()
That server_address tuple is a string containing the IP address ('1.2.101.202' or whatever), followed by an integer port number. So replace the string with your host machine's public-facing IP address.
Note that port 8000 is outside the reserved range (0 up to but not including 1024), so it's possible that some unrelated service is already using that port. (Numerous applications are already squatting port 8000.) If so, you'll just have to choose another port number. You can chose anything from 1024 up to but not including 65536, but as with 8000, someone else might already be using it.
Depending on your operating system and its security setup, you might not have permission to open a socket that listens on an arbitrary port number. If so, that's between you and your ISP or sysadmin.
http://yourip:port/func
yourip is your public ip.
port is 8080
func is your registered function.
and also make sure you port is opened
Server :
HOST = 'localhost'
PORT = 8000
Client :
HOST = '#MyIPAddress' (found on http://www.ip-adress.com/)
PORT = 8000
Client fails connecting to the server. It works if client.HOST = 'localhost' to but that's not the point. I forwarded my router to open that port. I want it to work over the internet. I tried stuff like https://pagekite.net/ but I couldn't make it work.
I would like to see any complete "hello world" example wich would send "hello world" through the internet between two clients. Either server runs on my computer or on a hosted platform I would like to see a full concrete example.
If your server and client are located at the same machine, then just
set client.HOST = 'localhost' as you said.
If your server and client are located at different machines, you
should try ping through each other.
If your server is behind an NAT device, you need to enable port
forwarding (such as upnp, dmz etc.) in order to make sure tcp
request from your client could reach your server first. What your
said sounds more like a network issue than a programming issue. Hope
this could help you.
Imagine you have a HTTP server on your local machine, this is a typical Python/Twisted application. This server is used to access your local data, server is used just as a GUI interface. So user can use his web browser or special application ( acts like a web browser ) to access his local data.
Now you want to be sure that only local user who physically sit near this machine get access to the HTTP server.
Also I will have FTP server and it must be protected the same way too.
At the moment I am running such code for my HTTP server:
class LocalSite(server.Site):
def buildProtocol(self, addr):
if addr.host != '127.0.0.1':
print 'WARNING connection from ' + str(addr)
return None
try:
res = server.Site.buildProtocol(self, addr)
except:
res = None
return res
So I am just check the IP address at the moment and I am not sure this is enough.
Is there any ways to emulate local IP from remote machine.?
Well, If a bad guy get access over my OS I have no way to protect - but this is not my deal. My firewall and antivirus should care about this, right?
Anyway, I would like to listen any extra ideas about increase security of such HTTP server.
May be we can use MAC address to verify connection.?
Check the processes on local machine and detect which is actually executes connection?
We can use HTTPS, but in my understanding this acts in opposite direction: this is for user to trust to the server, not server to trust to the user.
Using CAPTCHA is a kind of solution. But I do not like this at all (it strains users) and this will not work for FTP server.
I am also use random port number every time application starts.
The type of internet connection is not defined - this is a p2p application. Any user in the WEB can use my software and it must be protected against remote access.
I believe the way you handled it is good enough. About it being cross-platform, I believe it is as Windows(starting from windows 7) too maps localhost to 127.0.0.1 but for previous versions, you have to define localhost in the main hosts file.
i am still a novice in these areas so here is my question:
I want to see the dns request sent out by my browser (say chrome).so i set up a udp server in python with host='' and port=21567(can be anything other than the previlaged and reserved ones).i set my server to listen for connections using the udp.recvfrom(1024)
and set the proxy in my browser to localhost and respective port number so my browser should send the request to my server when i type in a url right??? is that right???
if it is then my server is not detecting a connection if it is wrong then please tell me the actual mechanism in technical details
Thanks in advance
Setting up a proxy in your browser tells it where to make TCP connections; it doesn't have anything to do with how it queries DNS, which is determined by your operating system's resolver.
For Linux you'd just shut down bind, e.g. Debian /etc/init.d/bind9 stop; then your Python script would catch the traffic on port 53. And make sure nameserver 127.0.0.1 is at the top of /etc/resolv.conf.
For Windows you'll need to set your DNS to the localhost (127.0.0.1), somewhere in the network settings.