mercurial/hgweb/common.py

dagparser: parses and formats DAGs as concise text

As discussed during the sprint. See the doc comment and doctests
for specification and examples. This is used in subsequent patches
to export revlog and changelog DAGs, and to generate a repo with
a given changelog DAG.

# hgweb/common.py - Utility functions needed by hgweb_mod and hgwebdir_mod
#
# Copyright 21 May 2005 - (c) 2005 Jake Edge <[e-mail]>
# Copyright 2005, 2006 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

import errno, mimetypes, os

HTTP_OK = 200
HTTP_BAD_REQUEST = 400
HTTP_UNAUTHORIZED = 401
HTTP_FORBIDDEN = 403
HTTP_NOT_FOUND = 404
HTTP_METHOD_NOT_ALLOWED = 405
HTTP_SERVER_ERROR = 500

# Hooks for hgweb permission checks; extensions can add hooks here. Each hook
# is invoked like this: hook(hgweb, request, operation), where operation is
# either read, pull or push. Hooks should either raise an ErrorResponse
# exception, or just return.
# It is possible to do both authentication and authorization through this.
permhooks = []

def checkauthz(hgweb, req, op):
    '''Check permission for operation based on request data (including
    authentication info). Return if op allowed, else raise an ErrorResponse
    exception.'''

    user = req.env.get('REMOTE_USER')

    deny_read = hgweb.configlist('web', 'deny_read')
    if deny_read and (not user or deny_read == ['*'] or user in deny_read):
        raise ErrorResponse(HTTP_UNAUTHORIZED, 'read not authorized')

    allow_read = hgweb.configlist('web', 'allow_read')
    result = (not allow_read) or (allow_read == ['*'])
    if not (result or user in allow_read):
        raise ErrorResponse(HTTP_UNAUTHORIZED, 'read not authorized')

    if op == 'pull' and not hgweb.allowpull:
        raise ErrorResponse(HTTP_UNAUTHORIZED, 'pull not authorized')
    elif op == 'pull' or op is None: # op is None for interface requests
        return

    # enforce that you can only push using POST requests
    if req.env['REQUEST_METHOD'] != 'POST':
        msg = 'push requires POST request'
        raise ErrorResponse(HTTP_METHOD_NOT_ALLOWED, msg)

    # require ssl by default for pushing, auth info cannot be sniffed
    # and replayed
    scheme = req.env.get('wsgi.url_scheme')
    if hgweb.configbool('web', 'push_ssl', True) and scheme != 'https':
        raise ErrorResponse(HTTP_OK, 'ssl required')

    deny = hgweb.configlist('web', 'deny_push')
    if deny and (not user or deny == ['*'] or user in deny):
        raise ErrorResponse(HTTP_UNAUTHORIZED, 'push not authorized')

    allow = hgweb.configlist('web', 'allow_push')
    result = allow and (allow == ['*'] or user in allow)
    if not result:
        raise ErrorResponse(HTTP_UNAUTHORIZED, 'push not authorized')

# Add the default permhook, which provides simple authorization.
permhooks.append(checkauthz)


class ErrorResponse(Exception):
    def __init__(self, code, message=None, headers=[]):
        Exception.__init__(self)
        self.code = code
        self.headers = headers
        if message is not None:
            self.message = message
        else:
            self.message = _statusmessage(code)

def _statusmessage(code):
    from BaseHTTPServer import BaseHTTPRequestHandler
    responses = BaseHTTPRequestHandler.responses
    return responses.get(code, ('Error', 'Unknown error'))[0]

def statusmessage(code, message=None):
    return '%d %s' % (code, message or _statusmessage(code))

def get_mtime(spath):
    cl_path = os.path.join(spath, "00changelog.i")
    if os.path.exists(cl_path):
        return os.stat(cl_path).st_mtime
    else:
        return os.stat(spath).st_mtime

def staticfile(directory, fname, req):
    """return a file inside directory with guessed Content-Type header

    fname always uses '/' as directory separator and isn't allowed to
    contain unusual path components.
    Content-Type is guessed using the mimetypes module.
    Return an empty string if fname is illegal or file not found.

    """
    parts = fname.split('/')
    for part in parts:
        if (part in ('', os.curdir, os.pardir) or
            os.sep in part or os.altsep is not None and os.altsep in part):
            return ""
    fpath = os.path.join(*parts)
    if isinstance(directory, str):
        directory = [directory]
    for d in directory:
        path = os.path.join(d, fpath)
        if os.path.exists(path):
            break
    try:
        os.stat(path)
        ct = mimetypes.guess_type(path)[0] or "text/plain"
        req.respond(HTTP_OK, ct, length = os.path.getsize(path))
        return open(path, 'rb').read()
    except TypeError:
        raise ErrorResponse(HTTP_SERVER_ERROR, 'illegal filename')
    except OSError, err:
        if err.errno == errno.ENOENT:
            raise ErrorResponse(HTTP_NOT_FOUND)
        else:
            raise ErrorResponse(HTTP_SERVER_ERROR, err.strerror)

def paritygen(stripecount, offset=0):
    """count parity of horizontal stripes for easier reading"""
    if stripecount and offset:
        # account for offset, e.g. due to building the list in reverse
        count = (stripecount + offset) % stripecount
        parity = (stripecount + offset) / stripecount & 1
    else:
        count = 0
        parity = 0
    while True:
        yield parity
        count += 1
        if stripecount and count >= stripecount:
            parity = 1 - parity
            count = 0

def get_contact(config):
    """Return repo contact information or empty string.

    web.contact is the primary source, but if that is not set, try
    ui.username or $EMAIL as a fallback to display something useful.
    """
    return (config("web", "contact") or
            config("ui", "username") or
            os.environ.get("EMAIL") or "")