mercurial/hgweb/hgweb_mod.py

hgweb: fail if an invalid command was supplied in url path (issue4071)

Traditionally, the way to specify a command for hgweb was to use url query
arguments (e.g. "?cmd=batch"). If the command is unknown to hgweb, it gives an
error (e.g. "400 no such method: badcmd").

But there's also another way to specify a command: as a url path fragment (e.g.
"/graph"). Before, hgweb was made forgiving (looks like it was made in
44c5157474e7) and user could put any unknown command in the url. If hgweb
couldn't understand it, it would just silently fall back to the default
command, which depends on the actual style (e.g. for paper it's shortlog, for
monoblue it's summary). This was inconsistent and was breaking some tools that
rely on http status codes (as noted in the issue4071). So this patch changes
that behavior to the more consistent one, i.e. hgweb will now return "400 no
such method: badcmd".

So if some tool was relying on having an invalid command return http status
code 200 and also have some information, then it will stop working. That is, if
somebody typed foobar when they really meant shortlog (and the user was lucky
enough to choose a style where the default command is shortlog too), that fact
will now be revealed.

Code-wise, the changed if block is only relevant when there's no "?cmd" query
parameter (i.e. only when command is specified as a url path fragment), and
looks like the removed else branch was there only for falling back to default
command. With that removed, the rest of the code works as expected: it looks at
the command, and if it's not known, raises a proper ErrorResponse exception
with an appropriate message.

Evidently, there were no tests that required the old behavior. But, frankly, I
don't know any way to tell if anyone actually exploited such forgiving behavior
in some in-house tool.

# hgweb/hgweb_mod.py - Web interface for a repository.
#
# Copyright 21 May 2005 - (c) 2005 Jake Edge <[e-mail]>
# Copyright 2005-2007 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 os, re
from mercurial import ui, hg, hook, error, encoding, templater, util, repoview
from mercurial.templatefilters import websub
from mercurial.i18n import _
from common import get_stat, ErrorResponse, permhooks, caching
from common import HTTP_OK, HTTP_NOT_MODIFIED, HTTP_BAD_REQUEST
from common import HTTP_NOT_FOUND, HTTP_SERVER_ERROR
from request import wsgirequest
import webcommands, protocol, webutil

perms = {
    'changegroup': 'pull',
    'changegroupsubset': 'pull',
    'getbundle': 'pull',
    'stream_out': 'pull',
    'listkeys': 'pull',
    'unbundle': 'push',
    'pushkey': 'push',
}

def makebreadcrumb(url, prefix=''):
    '''Return a 'URL breadcrumb' list

    A 'URL breadcrumb' is a list of URL-name pairs,
    corresponding to each of the path items on a URL.
    This can be used to create path navigation entries.
    '''
    if url.endswith('/'):
        url = url[:-1]
    if prefix:
        url = '/' + prefix + url
    relpath = url
    if relpath.startswith('/'):
        relpath = relpath[1:]

    breadcrumb = []
    urlel = url
    pathitems = [''] + relpath.split('/')
    for pathel in reversed(pathitems):
        if not pathel or not urlel:
            break
        breadcrumb.append({'url': urlel, 'name': pathel})
        urlel = os.path.dirname(urlel)
    return reversed(breadcrumb)


class hgweb(object):
    def __init__(self, repo, name=None, baseui=None):
        if isinstance(repo, str):
            if baseui:
                u = baseui.copy()
            else:
                u = ui.ui()
            r = hg.repository(u, repo)
        else:
            # we trust caller to give us a private copy
            r = repo

        r = self._getview(r)
        r.ui.setconfig('ui', 'report_untrusted', 'off', 'hgweb')
        r.baseui.setconfig('ui', 'report_untrusted', 'off', 'hgweb')
        r.ui.setconfig('ui', 'nontty', 'true', 'hgweb')
        r.baseui.setconfig('ui', 'nontty', 'true', 'hgweb')
        self.repo = r
        hook.redirect(True)
        self.mtime = -1
        self.size = -1
        self.reponame = name
        self.archives = 'zip', 'gz', 'bz2'
        self.stripecount = 1
        # a repo owner may set web.templates in .hg/hgrc to get any file
        # readable by the user running the CGI script
        self.templatepath = self.config('web', 'templates')
        self.websubtable = self.loadwebsub()

    # The CGI scripts are often run by a user different from the repo owner.
    # Trust the settings from the .hg/hgrc files by default.
    def config(self, section, name, default=None, untrusted=True):
        return self.repo.ui.config(section, name, default,
                                   untrusted=untrusted)

    def configbool(self, section, name, default=False, untrusted=True):
        return self.repo.ui.configbool(section, name, default,
                                       untrusted=untrusted)

    def configlist(self, section, name, default=None, untrusted=True):
        return self.repo.ui.configlist(section, name, default,
                                       untrusted=untrusted)

    def _getview(self, repo):
        viewconfig = repo.ui.config('web', 'view', 'served',
                                    untrusted=True)
        if viewconfig == 'all':
            return repo.unfiltered()
        elif viewconfig in repoview.filtertable:
            return repo.filtered(viewconfig)
        else:
            return repo.filtered('served')

    def refresh(self, request=None):
        st = get_stat(self.repo.spath)
        # compare changelog size in addition to mtime to catch
        # rollbacks made less than a second ago
        if st.st_mtime != self.mtime or st.st_size != self.size:
            r = hg.repository(self.repo.baseui, self.repo.root)
            self.repo = self._getview(r)
            self.maxchanges = int(self.config("web", "maxchanges", 10))
            self.stripecount = int(self.config("web", "stripes", 1))
            self.maxshortchanges = int(self.config("web", "maxshortchanges",
                                                   60))
            self.maxfiles = int(self.config("web", "maxfiles", 10))
            self.allowpull = self.configbool("web", "allowpull", True)
            encoding.encoding = self.config("web", "encoding",
                                            encoding.encoding)
            # update these last to avoid threads seeing empty settings
            self.mtime = st.st_mtime
            self.size = st.st_size
        if request:
            self.repo.ui.environ = request.env

    def run(self):
        if not os.environ.get('GATEWAY_INTERFACE', '').startswith("CGI/1."):
            raise RuntimeError("This function is only intended to be "
                               "called while running as a CGI script.")
        import mercurial.hgweb.wsgicgi as wsgicgi
        wsgicgi.launch(self)

    def __call__(self, env, respond):
        req = wsgirequest(env, respond)
        return self.run_wsgi(req)

    def run_wsgi(self, req):

        self.refresh(req)

        # work with CGI variables to create coherent structure
        # use SCRIPT_NAME, PATH_INFO and QUERY_STRING as well as our REPO_NAME

        req.url = req.env['SCRIPT_NAME']
        if not req.url.endswith('/'):
            req.url += '/'
        if 'REPO_NAME' in req.env:
            req.url += req.env['REPO_NAME'] + '/'

        if 'PATH_INFO' in req.env:
            parts = req.env['PATH_INFO'].strip('/').split('/')
            repo_parts = req.env.get('REPO_NAME', '').split('/')
            if parts[:len(repo_parts)] == repo_parts:
                parts = parts[len(repo_parts):]
            query = '/'.join(parts)
        else:
            query = req.env['QUERY_STRING'].split('&', 1)[0]
            query = query.split(';', 1)[0]

        # process this if it's a protocol request
        # protocol bits don't need to create any URLs
        # and the clients always use the old URL structure

        cmd = req.form.get('cmd', [''])[0]
        if protocol.iscmd(cmd):
            try:
                if query:
                    raise ErrorResponse(HTTP_NOT_FOUND)
                if cmd in perms:
                    self.check_perm(req, perms[cmd])
                return protocol.call(self.repo, req, cmd)
            except ErrorResponse, inst:
                # A client that sends unbundle without 100-continue will
                # break if we respond early.
                if (cmd == 'unbundle' and
                    (req.env.get('HTTP_EXPECT',
                                 '').lower() != '100-continue') or
                    req.env.get('X-HgHttp2', '')):
                    req.drain()
                else:
                    req.headers.append(('Connection', 'Close'))
                req.respond(inst, protocol.HGTYPE,
                            body='0\n%s\n' % inst.message)
                return ''

        # translate user-visible url structure to internal structure

        args = query.split('/', 2)
        if 'cmd' not in req.form and args and args[0]:

            cmd = args.pop(0)
            style = cmd.rfind('-')
            if style != -1:
                req.form['style'] = [cmd[:style]]
                cmd = cmd[style + 1:]

            # avoid accepting e.g. style parameter as command
            if util.safehasattr(webcommands, cmd):
                req.form['cmd'] = [cmd]

            if cmd == 'static':
                req.form['file'] = ['/'.join(args)]
            else:
                if args and args[0]:
                    node = args.pop(0)
                    req.form['node'] = [node]
                if args:
                    req.form['file'] = args

            ua = req.env.get('HTTP_USER_AGENT', '')
            if cmd == 'rev' and 'mercurial' in ua:
                req.form['style'] = ['raw']

            if cmd == 'archive':
                fn = req.form['node'][0]
                for type_, spec in self.archive_specs.iteritems():
                    ext = spec[2]
                    if fn.endswith(ext):
                        req.form['node'] = [fn[:-len(ext)]]
                        req.form['type'] = [type_]

        # process the web interface request

        try:
            tmpl = self.templater(req)
            ctype = tmpl('mimetype', encoding=encoding.encoding)
            ctype = templater.stringify(ctype)

            # check read permissions non-static content
            if cmd != 'static':
                self.check_perm(req, None)

            if cmd == '':
                req.form['cmd'] = [tmpl.cache['default']]
                cmd = req.form['cmd'][0]

            if self.configbool('web', 'cache', True):
                caching(self, req) # sets ETag header or raises NOT_MODIFIED
            if cmd not in webcommands.__all__:
                msg = 'no such method: %s' % cmd
                raise ErrorResponse(HTTP_BAD_REQUEST, msg)
            elif cmd == 'file' and 'raw' in req.form.get('style', []):
                self.ctype = ctype
                content = webcommands.rawfile(self, req, tmpl)
            else:
                content = getattr(webcommands, cmd)(self, req, tmpl)
                req.respond(HTTP_OK, ctype)

            return content

        except (error.LookupError, error.RepoLookupError), err:
            req.respond(HTTP_NOT_FOUND, ctype)
            msg = str(err)
            if (util.safehasattr(err, 'name') and
                not isinstance(err,  error.ManifestLookupError)):
                msg = 'revision not found: %s' % err.name
            return tmpl('error', error=msg)
        except (error.RepoError, error.RevlogError), inst:
            req.respond(HTTP_SERVER_ERROR, ctype)
            return tmpl('error', error=str(inst))
        except ErrorResponse, inst:
            req.respond(inst, ctype)
            if inst.code == HTTP_NOT_MODIFIED:
                # Not allowed to return a body on a 304
                return ['']
            return tmpl('error', error=inst.message)

    def loadwebsub(self):
        websubtable = []
        websubdefs = self.repo.ui.configitems('websub')
        # we must maintain interhg backwards compatibility
        websubdefs += self.repo.ui.configitems('interhg')
        for key, pattern in websubdefs:
            # grab the delimiter from the character after the "s"
            unesc = pattern[1]
            delim = re.escape(unesc)

            # identify portions of the pattern, taking care to avoid escaped
            # delimiters. the replace format and flags are optional, but
            # delimiters are required.
            match = re.match(
                r'^s%s(.+)(?:(?<=\\\\)|(?<!\\))%s(.*)%s([ilmsux])*$'
                % (delim, delim, delim), pattern)
            if not match:
                self.repo.ui.warn(_("websub: invalid pattern for %s: %s\n")
                                  % (key, pattern))
                continue

            # we need to unescape the delimiter for regexp and format
            delim_re = re.compile(r'(?<!\\)\\%s' % delim)
            regexp = delim_re.sub(unesc, match.group(1))
            format = delim_re.sub(unesc, match.group(2))

            # the pattern allows for 6 regexp flags, so set them if necessary
            flagin = match.group(3)
            flags = 0
            if flagin:
                for flag in flagin.upper():
                    flags |= re.__dict__[flag]

            try:
                regexp = re.compile(regexp, flags)
                websubtable.append((regexp, format))
            except re.error:
                self.repo.ui.warn(_("websub: invalid regexp for %s: %s\n")
                                  % (key, regexp))
        return websubtable

    def templater(self, req):

        # determine scheme, port and server name
        # this is needed to create absolute urls

        proto = req.env.get('wsgi.url_scheme')
        if proto == 'https':
            proto = 'https'
            default_port = "443"
        else:
            proto = 'http'
            default_port = "80"

        port = req.env["SERVER_PORT"]
        port = port != default_port and (":" + port) or ""
        urlbase = '%s://%s%s' % (proto, req.env['SERVER_NAME'], port)
        logourl = self.config("web", "logourl", "http://mercurial.selenic.com/")
        logoimg = self.config("web", "logoimg", "hglogo.png")
        staticurl = self.config("web", "staticurl") or req.url + 'static/'
        if not staticurl.endswith('/'):
            staticurl += '/'

        # some functions for the templater

        def motd(**map):
            yield self.config("web", "motd", "")

        # figure out which style to use

        vars = {}
        styles = (
            req.form.get('style', [None])[0],
            self.config('web', 'style'),
            'paper',
        )
        style, mapfile = templater.stylemap(styles, self.templatepath)
        if style == styles[0]:
            vars['style'] = style

        start = req.url[-1] == '?' and '&' or '?'
        sessionvars = webutil.sessionvars(vars, start)

        if not self.reponame:
            self.reponame = (self.config("web", "name")
                             or req.env.get('REPO_NAME')
                             or req.url.strip('/') or self.repo.root)

        def websubfilter(text):
            return websub(text, self.websubtable)

        # create the templater

        tmpl = templater.templater(mapfile,
                                   filters={"websub": websubfilter},
                                   defaults={"url": req.url,
                                             "logourl": logourl,
                                             "logoimg": logoimg,
                                             "staticurl": staticurl,
                                             "urlbase": urlbase,
                                             "repo": self.reponame,
                                             "encoding": encoding.encoding,
                                             "motd": motd,
                                             "sessionvars": sessionvars,
                                             "pathdef": makebreadcrumb(req.url),
                                             "style": style,
                                            })
        return tmpl

    def archivelist(self, nodeid):
        allowed = self.configlist("web", "allow_archive")
        for i, spec in self.archive_specs.iteritems():
            if i in allowed or self.configbool("web", "allow" + i):
                yield {"type" : i, "extension" : spec[2], "node" : nodeid}

    archive_specs = {
        'bz2': ('application/x-bzip2', 'tbz2', '.tar.bz2', None),
        'gz': ('application/x-gzip', 'tgz', '.tar.gz', None),
        'zip': ('application/zip', 'zip', '.zip', None),
        }

    def check_perm(self, req, op):
        for hook in permhooks:
            hook(self, req, op)