ImportError: No module named twisted.internet

Question

I installed python 2.7.5 which is working fine.

I then install scrapy (which, I think, uses twisted internally). My scrapy spider is also working fine.

I installed twisted:

sudo apt-get install python-twisted

Then, I created a sample program using Echo Server code shown here

Here is the code

from twisted.internet import protocol, reactor


class Echo(protocol.Protocol):
    def dataReceived(self, data):
        self.transport.write(data)

class EchoFactory(protocol.Factory):
    def buildProtocol(self, addr):
        return Echo()

reactor.listenTCP(1234, EchoFactory())
reactor.run()

I try to run this code using this command:

$ python twistedTester.py 
Traceback (most recent call last):
  File "twistedTester.py", line 1, in <module>
    from twisted.internet import protocol, reactor
ImportError: No module named twisted.internet

Can anyone help me with how I can debug why my twisted package is not being picked up by Python installation?

Answer 1

If you use pip just try:

pip install twisted

The same works with w3lib and lxml.

On some *nix systems this might give you a permission error. If that happens, try:

sudo -H pip install twisted

Answer 2

I figured out why this error was happening. For some reason, using apt-get to install a python package was not installing it right.

So, I had to download a tar ball and install the package from them.

I downloaded Twisted tar from here.

I did a tar xjf Twisted-13.1.0.tar.bz2 - this created a directory called Twisted-13.1.0

next, cd Twisted-13.1.0 Finally, python setup.py install

This gave me an error. Twisted required another package called zope.interface. So, I downloaded tar ball for zope.interface from here. Then, ran this command tar xzf zope.interface-3.6.1.tar.gz That created a folder called zope.interface-3.6.1. So, cd into zope.interface-3.6.1 and run python setup.py install

Note: Depending on your user's rights, you may want to do these commands in sudo mode. Just add the keyword sudo before every command.