= Publishing Repositories Using CherryPy =
=== Introduction ===
For a really really simple way of publishing your Mercurial repositories on the Web without the need for Apache or IIS.

Some quotes from the !CherryPy Web site:
  !CherryPy is a pythonic, object-oriented HTTP framework.

  !CherryPy powered web applications are in fact stand-alone Python applications embedding their own multi-threaded web server.

  !CherryPy applications run on Windows, Linux, Mac OS X and any other platform supporting Python.
!CherryPy can run WSGI compliant applications like ~+`hgweb`+~ and ~+`hgwebdir`+~.

=== Pre-requisites ===
Python 2.4 or newer (http://www.python.org/download/)

!CherryPy 3.1 or newer (http://www.cherrypy.org/)

If you want authentication you will need Paste (http://pypi.python.org/pypi/Paste), I used version 1.7.2

Read PublishingRepositories and HgWebDirStepByStep first to get an understanding of ~+`hgweb`+~, ~+`hgwebdir`+~, the ~+`hgweb.config`+~ file and Mercurial ~+`Lib`+~ folder setup.

== Running HgWebDir ==
Here is my sample code that uses the ~+`hgwebdir`+~ module.  Edit this code to suit your needs:
{{{
#!python
# cphgwebdir.py

# Adjust host and port to suit your Web presence:
sUrlHost='0.0.0.0'
iUrlPort=8080

# Adjust encoding to suit or comment out:
import os
os.environ['HGENCODING']='UTF-8'

import sys
# Adjust path to your Mercurial Lib folder:
sys.path.append(r'C:\Program Files\Mercurial\Lib')
from mercurial.hgweb.hgwebdir_mod import hgwebdir

import cherrypy
cherrypy.config.update({
    # Default is development environment, uncomment below when in production
    #'environment':'production',
    'server.socket_host':sUrlHost,
    'server.socket_port':iUrlPort,
    #'log.access_file':'access.log',
    'log.error_file':'error.log',
    'log.screen':True
})
# Use same hgweb.config file as for hgwebdir.cgi
cherrypy.tree.graft(hgwebdir('hgweb.config'),script_name='/')
cherrypy.engine.start()
cherrypy.engine.block()
}}}

~+`sUrlHost`+~ can be IP number or domain name (usually, depending on how your network is set up).

Save this code into the same folder as ~+`hgweb.config`+~.  Unless you have added a path, then save to the root of that path.

Suggested filename is ~+`cphgwebdir.py`+~

From a command line just execute the file, like this from its folder:
{{{
/path/to/python cphgwebdir.py
}}}
That's it.
== Running HgWebDir with Digest Authentication ==
This is a modification of the above code.  Edit this code to suit your needs:
{{{
#!python
# cphgwebdir.py with digest authentication
import os
import sys
import cherrypy
from paste.auth.digest import AuthDigestHandler, digest_password

# Adjust host and port to suit your Web presence:
sUrlHost='0.0.0.0'
iUrlPort=8080

# Adjust encoding to suit or comment out:
os.environ['HGENCODING']='UTF-8'

# Adjust path to your Mercurial Lib folder:
sys.path.append(r'C:\Program Files\Mercurial\Lib')
from mercurial.hgweb.hgwebdir_mod import hgwebdir

# Use same hgweb.config file as for hgwebdir.cgi
WsgiApp=hgwebdir('hgweb.config')

# Adjust realm to suit your needs
Realm='Mercurial Repositories'

# This is a sample dictionary of valid users with their digest encrypted password
dAuth={}
dAuth['Alice']=digest_password(Realm,'Alice','secret')
dAuth['Dilbert']=digest_password(Realm,'Dilbert','secret')
dAuth['Wally']=digest_password(Realm,'Wally','secret')
#dAuth['<username>']=digest_password('<realm>','<username>','<password>')

def AuthFunc(environ,realm,username):
    return dAuth.get(username,None)

WsgiApp=AuthDigestHandler(WsgiApp,Realm,AuthFunc)

cherrypy.config.update({
    # Default is development environment, uncomment below when in production
    #'environment':'production',
    'server.socket_host':sUrlHost,
    'server.socket_port':iUrlPort,
    #'log.access_file':'access.log',
    'log.error_file':'error.log',
    'log.screen':True
})
cherrypy.tree.graft(WsgiApp,script_name='/')
cherrypy.engine.start()
cherrypy.engine.block()
}}}
Note: do not try ~+`tools.wsgiapp`+~ as it does not work in this case and has been deprecated, and will be removed in Cherrypy 3.2

== Running HgWeb ==
Use this if you don't want the fancy browser front-end.

Here is my sample code that uses the ~+`hgweb`+~ module.  Edit this code to suit your needs:
{{{
#!python
# cphgweb.py

# Adjust host and port to suit your Web presence:
sUrlHost='0.0.0.0'
iUrlPort=8080

# Change this to represent your repository/ies:
lRepos=[
    #('<virtual path>','<absolute path>'),
    ('/project1',r'C:\Program Files\DemoRepos\project1'),
    ('/project2',r'C:\Program Files\DemoRepos\project2'),
    ('/project3',r'C:\Program Files\DemoRepos\project3')
]

# Adjust encoding to suit or comment out:
import os
os.environ['HGENCODING']='UTF-8'

import sys
# Adjust path to your Mercurial Lib folder:
sys.path.append(r'C:\Program Files\Mercurial\Lib')
from mercurial.hgweb.hgweb_mod import hgweb

import cherrypy
cherrypy.config.update({
    # Default is development environment, uncomment below when in production
    #'environment':'production',
    'engine.autoreload.on':True,
    'server.socket_host':sUrlHost,
    'server.socket_port':iUrlPort,
    'log.error_file':'error.log',
    'log.screen':True
})
for (sName,sPath) in lRepos:
    cherrypy.tree.graft(hgweb(sPath),script_name=sName)
cherrypy.engine.start()
cherrypy.engine.block()
}}}

~+`sUrlHost`+~ can be IP number or domain name (usually, depending on how your network is set up).

Change tuples in ~+`lRepos`+~ list to indicate the repositories that you want published, first element of each tuple must have a leading forward slash.

Suggested filename is ~+`cphgweb.py`+~

From a command line just execute the file, like this from its folder:
{{{
/path/to/python cphgweb.py
}}}
You can make changes to the ~+`lRepos`+~ list while it is running, saving changes will initiate a restart.

Example command:
{{{
hg clone "http://192.168.0.10:8080/project2"
}}}

== Running HgWebDir As a Windows Service ==

Here is some example code on how to run hgwebdir and cherrypy as a windows service. It is basically a combination of the above example and the example from cherry's web site: http://tools.cherrypy.org/wiki/WindowsService. 

Notice the assignments to sys.__stdout__ and sys.__stderr__ without them you'll get a 500 internal error back when running as a service. It will however run fine in debug mode. Took me a while to figure that out ;-)

{{{
#!python
# cphgwebdir.py

URL_HOST = '127.0.0.1'
URL_PORT = 4040

import sys
import os

import cherrypy
import win32serviceutil
import win32service
import win32event


os.environ['HGENCODING'] = 'UTF-8'
# Change current working dir to the path where hgweb.config is located.
os.chdir('D:/Projects/python/cphgweb')

class MercurialService(win32serviceutil.ServiceFramework):
    """Windows Service"""

    _svc_name_         = "hgservice"
    _svc_display_name_ = "Mercurial Service"

    def __init__(self, args):
        win32serviceutil.ServiceFramework.__init__(self, args)
        # Create an event that SvcDoRun can wait on and SvcStop
        # can set.
        self.stop_event = win32event.CreateEvent(None, 0, 0, None)
    
    def SvcDoRun(self):
        from mercurial.hgweb.hgwebdir_mod import hgwebdir
   
        # Set __stdout__ and __stderr__ to avoid mercurial/hook.py from 
        # throwing an OSError in the hook function when attempting to
        # redirect stdout to stderr.
        sys.__stdout__ = open('NUL', 'a+')
        sys.__stderr__ = open('NUL', 'a+')

        cherrypy.tree.graft(hgwebdir('hgweb.config'), script_name='/')

        cherrypy.config.update({
            'global':{
                #'environment':'production',
                'engine.autoreload_on': False,
                'server.socket_host':URL_HOST,
                'server.socket_port':URL_PORT,
                'log.screen': False,
                'log.error_file':'D:/Projects/python/cphgweb/error.log',
                'engine.SIGHUP': None,
                'engine.SIGTERM': None,
                }
            })
        
        cherrypy.engine.start()

        # now, block until our event is set...
        win32event.WaitForSingleObject(self.stop_event, win32event.INFINITE)

    def SvcStop(self):
        self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING)
        cherrypy.server.stop()
        win32event.SetEvent(self.stop_event)


if __name__ == '__main__':
    win32serviceutil.HandleCommandLine(MercurialService)
}}}

Run:

{{{
python cphgwebdir.py install
python cphgwebdir.py start
}}}

And your service should be running.

=== SSL Problem with Windows Service ===
If you modify the above Windows Service code to add SSL support you may receive the following Windows error message after the service starts causing it to quickly fail:
 Application popup: PythonService.exe - Application Error :
  The instruction at "0x77fcb333" referenced memory at "0x00000000".
   The memory could not be "written".
I have fixed this by adding the following code after ~+`import cherrypy`+~ :
{{{
#!python
from cherrypy import _cpwsgi_server# to fix PythonService.exe SSL problem
}}}
My implementation also includes the authentication code and runs under Win2000.
----
CategoryHowTo