hgweb: inline caching() and port to modern mechanisms

We only had one consumer of this simple function. While it could be
a generic function, let's not over abstract the code.

As part of inlining, we port it off wsgirequest, fix some Python 3
issues, and set a response header on our new response object so it
is ready once we start using it to send responses.

Differential Revision: https://phab.mercurial-scm.org/D2785

mercurial/hgweb/common.py

@@ -1,257 +1,251 b''
 # 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.
 
 from __future__ import absolute_import
 
 import base64
 import errno
 import mimetypes
 import os
 import stat
 
 from .. import (
     encoding,
     pycompat,
     util,
 )
 
 httpserver = util.httpserver
 
 HTTP_OK = 200
 HTTP_NOT_MODIFIED = 304
 HTTP_BAD_REQUEST = 400
 HTTP_UNAUTHORIZED = 401
 HTTP_FORBIDDEN = 403
 HTTP_NOT_FOUND = 404
 HTTP_METHOD_NOT_ALLOWED = 405
 HTTP_SERVER_ERROR = 500
 
 
 def ismember(ui, username, userlist):
     """Check if username is a member of userlist.
 
     If userlist has a single '*' member, all users are considered members.
     Can be overridden by extensions to provide more complex authorization
     schemes.
     """
     return userlist == ['*'] or username in userlist
 
 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(r'REMOTE_USER')
 
     deny_read = hgweb.configlist('web', 'deny_read')
     if deny_read and (not user or ismember(hgweb.repo.ui, user, deny_read)):
         raise ErrorResponse(HTTP_UNAUTHORIZED, 'read not authorized')
 
     allow_read = hgweb.configlist('web', 'allow_read')
     if allow_read and (not ismember(hgweb.repo.ui, user, 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[r'REQUEST_METHOD'] != r'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') and scheme != 'https':
         raise ErrorResponse(HTTP_FORBIDDEN, 'ssl required')
 
     deny = hgweb.configlist('web', 'deny_push')
     if deny and (not user or ismember(hgweb.repo.ui, user, deny)):
         raise ErrorResponse(HTTP_UNAUTHORIZED, 'push not authorized')
 
     allow = hgweb.configlist('web', 'allow-push')
     if not (allow and ismember(hgweb.repo.ui, user, allow)):
         raise ErrorResponse(HTTP_UNAUTHORIZED, 'push not authorized')
 
 # 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 = [checkauthz]
 
 
 class ErrorResponse(Exception):
     def __init__(self, code, message=None, headers=None):
         if message is None:
             message = _statusmessage(code)
         Exception.__init__(self, pycompat.sysstr(message))
         self.code = code
         if headers is None:
             headers = []
         self.headers = headers
 
 class continuereader(object):
     """File object wrapper to handle HTTP 100-continue.
 
     This is used by servers so they automatically handle Expect: 100-continue
     request headers. On first read of the request body, the 100 Continue
     response is sent. This should trigger the client into actually sending
     the request body.
     """
     def __init__(self, f, write):
         self.f = f
         self._write = write
         self.continued = False
 
     def read(self, amt=-1):
         if not self.continued:
             self.continued = True
             self._write('HTTP/1.1 100 Continue\r\n\r\n')
         return self.f.read(amt)
 
     def __getattr__(self, attr):
         if attr in ('close', 'readline', 'readlines', '__iter__'):
             return getattr(self.f, attr)
         raise AttributeError
 
 def _statusmessage(code):
     responses = httpserver.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_stat(spath, fn):
     """stat fn if it exists, spath otherwise"""
     cl_path = os.path.join(spath, fn)
     if os.path.exists(cl_path):
         return os.stat(cl_path)
     else:
         return os.stat(spath)
 
 def get_mtime(spath):
     return get_stat(spath, "00changelog.i")[stat.ST_MTIME]
 
 def ispathsafe(path):
     """Determine if a path is safe to use for filesystem access."""
     parts = path.split('/')
     for part in parts:
         if (part in ('', pycompat.oscurdir, pycompat.ospardir) or
             pycompat.ossep in part or
             pycompat.osaltsep is not None and pycompat.osaltsep in part):
             return False
 
     return True
 
 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.
 
     """
     if not ispathsafe(fname):
         return
 
     fpath = os.path.join(*fname.split('/'))
     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(pycompat.fsdecode(path))[0] or "text/plain"
         with open(path, 'rb') as fh:
             data = fh.read()
 
         req.respond(HTTP_OK, ct, body=data)
     except TypeError:
         raise ErrorResponse(HTTP_SERVER_ERROR, 'illegal filename')
     except OSError as err:
         if err.errno == errno.ENOENT:
             raise ErrorResponse(HTTP_NOT_FOUND)
         else:
             raise ErrorResponse(HTTP_SERVER_ERROR,
                                 encoding.strtolocal(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
             encoding.environ.get("EMAIL") or "")
 
-def caching(web, req):
-    tag = r'W/"%d"' % web.mtime
-    if req.env.get('HTTP_IF_NONE_MATCH') == tag:
-        raise ErrorResponse(HTTP_NOT_MODIFIED)
-    req.headers.append(('ETag', tag))
-
 def cspvalues(ui):
     """Obtain the Content-Security-Policy header and nonce value.
 
     Returns a 2-tuple of the CSP header value and the nonce value.
 
     First value is ``None`` if CSP isn't enabled. Second value is ``None``
     if CSP isn't enabled or if the CSP header doesn't need a nonce.
     """
     # Without demandimport, "import uuid" could have an immediate side-effect
     # running "ldconfig" on Linux trying to find libuuid.
     # With Python <= 2.7.12, that "ldconfig" is run via a shell and the shell
     # may pollute the terminal with:
     #
     #   shell-init: error retrieving current directory: getcwd: cannot access
     #   parent directories: No such file or directory
     #
     # Python >= 2.7.13 has fixed it by running "ldconfig" directly without a
     # shell (hg changeset a09ae70f3489).
     #
     # Moved "import uuid" from here so it's executed after we know we have
     # a sane cwd (i.e. after dispatch.py cwd check).
     #
     # We can move it back once we no longer need Python <= 2.7.12 support.
     import uuid
 
     # Don't allow untrusted CSP setting since it be disable protections
     # from a trusted/global source.
     csp = ui.config('web', 'csp', untrusted=False)
     nonce = None
 
     if csp and '%nonce%' in csp:
         nonce = base64.urlsafe_b64encode(uuid.uuid4().bytes).rstrip('=')
         csp = csp.replace('%nonce%', nonce)
 
     return csp, nonce

mercurial/hgweb/hgweb_mod.py

@@ -1,443 +1,448 b''
 # 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.
 
 from __future__ import absolute_import
 
 import contextlib
 import os
 
 from .common import (
     ErrorResponse,
     HTTP_BAD_REQUEST,
     HTTP_NOT_FOUND,
     HTTP_NOT_MODIFIED,
     HTTP_OK,
     HTTP_SERVER_ERROR,
-    caching,
     cspvalues,
     permhooks,
 )
 
 from .. import (
     encoding,
     error,
     formatter,
     hg,
     hook,
     profiling,
     pycompat,
     repoview,
     templatefilters,
     templater,
     ui as uimod,
     util,
     wireprotoserver,
 )
 
 from . import (
     request as requestmod,
     webcommands,
     webutil,
     wsgicgi,
 )
 
 archivespecs = util.sortdict((
     ('zip', ('application/zip', 'zip', '.zip', None)),
     ('gz', ('application/x-gzip', 'tgz', '.tar.gz', None)),
     ('bz2', ('application/x-bzip2', 'tbz2', '.tar.bz2', None)),
 ))
 
 def getstyle(req, configfn, templatepath):
     styles = (
         req.qsparams.get('style', None),
         configfn('web', 'style'),
         'paper',
     )
     return styles, templater.stylemap(styles, templatepath)
 
 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 requestcontext(object):
     """Holds state/context for an individual request.
 
     Servers can be multi-threaded. Holding state on the WSGI application
     is prone to race conditions. Instances of this class exist to hold
     mutable and race-free state for requests.
     """
     def __init__(self, app, repo):
         self.repo = repo
         self.reponame = app.reponame
 
         self.archivespecs = archivespecs
 
         self.maxchanges = self.configint('web', 'maxchanges')
         self.stripecount = self.configint('web', 'stripes')
         self.maxshortchanges = self.configint('web', 'maxshortchanges')
         self.maxfiles = self.configint('web', 'maxfiles')
         self.allowpull = self.configbool('web', 'allow-pull')
 
         # we use untrusted=False to prevent a repo owner from using
         # web.templates in .hg/hgrc to get access to any file readable
         # by the user running the CGI script
         self.templatepath = self.config('web', 'templates', untrusted=False)
 
         # This object is more expensive to build than simple config values.
         # It is shared across requests. The app will replace the object
         # if it is updated. Since this is a reference and nothing should
         # modify the underlying object, it should be constant for the lifetime
         # of the request.
         self.websubtable = app.websubtable
 
         self.csp, self.nonce = cspvalues(self.repo.ui)
 
     # Trust the settings from the .hg/hgrc files by default.
     def config(self, section, name, default=uimod._unset, untrusted=True):
         return self.repo.ui.config(section, name, default,
                                    untrusted=untrusted)
 
     def configbool(self, section, name, default=uimod._unset, untrusted=True):
         return self.repo.ui.configbool(section, name, default,
                                        untrusted=untrusted)
 
     def configint(self, section, name, default=uimod._unset, untrusted=True):
         return self.repo.ui.configint(section, name, default,
                                       untrusted=untrusted)
 
     def configlist(self, section, name, default=uimod._unset, untrusted=True):
         return self.repo.ui.configlist(section, name, default,
                                        untrusted=untrusted)
 
     def archivelist(self, nodeid):
         allowed = self.configlist('web', 'allow_archive')
         for typ, spec in self.archivespecs.iteritems():
             if typ in allowed or self.configbool('web', 'allow%s' % typ):
                 yield {'type': typ, 'extension': spec[2], 'node': nodeid}
 
     def templater(self, req):
         # determine scheme, port and server name
         # this is needed to create absolute urls
         logourl = self.config('web', 'logourl')
         logoimg = self.config('web', 'logoimg')
         staticurl = (self.config('web', 'staticurl')
                      or req.apppath + '/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, (style, mapfile) = getstyle(req, self.config,
                                             self.templatepath)
         if style == styles[0]:
             vars['style'] = style
 
         sessionvars = webutil.sessionvars(vars, '?')
 
         if not self.reponame:
             self.reponame = (self.config('web', 'name', '')
                              or req.reponame
                              or req.apppath
                              or self.repo.root)
 
         def websubfilter(text):
             return templatefilters.websub(text, self.websubtable)
 
         # create the templater
         # TODO: export all keywords: defaults = templatekw.keywords.copy()
         defaults = {
             'url': req.apppath + '/',
             'logourl': logourl,
             'logoimg': logoimg,
             'staticurl': staticurl,
             'urlbase': req.advertisedbaseurl,
             'repo': self.reponame,
             'encoding': encoding.encoding,
             'motd': motd,
             'sessionvars': sessionvars,
             'pathdef': makebreadcrumb(req.apppath),
             'style': style,
             'nonce': self.nonce,
         }
         tres = formatter.templateresources(self.repo.ui, self.repo)
         tmpl = templater.templater.frommapfile(mapfile,
                                                filters={'websub': websubfilter},
                                                defaults=defaults,
                                                resources=tres)
         return tmpl
 
 
 class hgweb(object):
     """HTTP server for individual repositories.
 
     Instances of this class serve HTTP responses for a particular
     repository.
 
     Instances are typically used as WSGI applications.
 
     Some servers are multi-threaded. On these servers, there may
     be multiple active threads inside __call__.
     """
     def __init__(self, repo, name=None, baseui=None):
         if isinstance(repo, str):
             if baseui:
                 u = baseui.copy()
             else:
                 u = uimod.ui.load()
             r = hg.repository(u, repo)
         else:
             # we trust caller to give us a private copy
             r = repo
 
         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')
         # resolve file patterns relative to repo root
         r.ui.setconfig('ui', 'forcecwd', r.root, 'hgweb')
         r.baseui.setconfig('ui', 'forcecwd', r.root, 'hgweb')
         # displaying bundling progress bar while serving feel wrong and may
         # break some wsgi implementation.
         r.ui.setconfig('progress', 'disable', 'true', 'hgweb')
         r.baseui.setconfig('progress', 'disable', 'true', 'hgweb')
         self._repos = [hg.cachedlocalrepo(self._webifyrepo(r))]
         self._lastrepo = self._repos[0]
         hook.redirect(True)
         self.reponame = name
 
     def _webifyrepo(self, repo):
         repo = getwebview(repo)
         self.websubtable = webutil.getwebsubs(repo)
         return repo
 
     @contextlib.contextmanager
     def _obtainrepo(self):
         """Obtain a repo unique to the caller.
 
         Internally we maintain a stack of cachedlocalrepo instances
         to be handed out. If one is available, we pop it and return it,
         ensuring it is up to date in the process. If one is not available,
         we clone the most recently used repo instance and return it.
 
         It is currently possible for the stack to grow without bounds
         if the server allows infinite threads. However, servers should
         have a thread limit, thus establishing our limit.
         """
         if self._repos:
             cached = self._repos.pop()
             r, created = cached.fetch()
         else:
             cached = self._lastrepo.copy()
             r, created = cached.fetch()
         if created:
             r = self._webifyrepo(r)
 
         self._lastrepo = cached
         self.mtime = cached.mtime
         try:
             yield r
         finally:
             self._repos.append(cached)
 
     def run(self):
         """Start a server from CGI environment.
 
         Modern servers should be using WSGI and should avoid this
         method, if possible.
         """
         if not encoding.environ.get('GATEWAY_INTERFACE',
                                     '').startswith("CGI/1."):
             raise RuntimeError("This function is only intended to be "
                                "called while running as a CGI script.")
         wsgicgi.launch(self)
 
     def __call__(self, env, respond):
         """Run the WSGI application.
 
         This may be called by multiple threads.
         """
         req = requestmod.wsgirequest(env, respond)
         return self.run_wsgi(req)
 
     def run_wsgi(self, wsgireq):
         """Internal method to run the WSGI application.
 
         This is typically only called by Mercurial. External consumers
         should be using instances of this class as the WSGI application.
         """
         with self._obtainrepo() as repo:
             profile = repo.ui.configbool('profiling', 'enabled')
             with profiling.profile(repo.ui, enabled=profile):
                 for r in self._runwsgi(wsgireq, repo):
                     yield r
 
     def _runwsgi(self, wsgireq, repo):
         req = wsgireq.req
         res = wsgireq.res
         rctx = requestcontext(self, repo)
 
         # This state is global across all threads.
         encoding.encoding = rctx.config('web', 'encoding')
         rctx.repo.ui.environ = wsgireq.env
 
         if rctx.csp:
             # hgwebdir may have added CSP header. Since we generate our own,
             # replace it.
             wsgireq.headers = [h for h in wsgireq.headers
                                if h[0] != 'Content-Security-Policy']
             wsgireq.headers.append(('Content-Security-Policy', rctx.csp))
             res.headers['Content-Security-Policy'] = rctx.csp
 
         handled = wireprotoserver.handlewsgirequest(
             rctx, wsgireq, req, res, self.check_perm)
         if handled:
             return res.sendresponse()
 
         if req.havepathinfo:
             query = req.dispatchpath
         else:
             query = req.querystring.partition('&')[0].partition(';')[0]
 
         # translate user-visible url structure to internal structure
 
         args = query.split('/', 2)
         if 'cmd' not in req.qsparams and args and args[0]:
             cmd = args.pop(0)
             style = cmd.rfind('-')
             if style != -1:
                 req.qsparams['style'] = cmd[:style]
                 cmd = cmd[style + 1:]
 
             # avoid accepting e.g. style parameter as command
             if util.safehasattr(webcommands, cmd):
                 req.qsparams['cmd'] = cmd
 
             if cmd == 'static':
                 req.qsparams['file'] = '/'.join(args)
             else:
                 if args and args[0]:
                     node = args.pop(0).replace('%2F', '/')
                     req.qsparams['node'] = node
                 if args:
                     if 'file' in req.qsparams:
                         del req.qsparams['file']
                     for a in args:
                         req.qsparams.add('file', a)
 
             ua = req.headers.get('User-Agent', '')
             if cmd == 'rev' and 'mercurial' in ua:
                 req.qsparams['style'] = 'raw'
 
             if cmd == 'archive':
                 fn = req.qsparams['node']
                 for type_, spec in rctx.archivespecs.iteritems():
                     ext = spec[2]
                     if fn.endswith(ext):
                         req.qsparams['node'] = fn[:-len(ext)]
                         req.qsparams['type'] = type_
         else:
             cmd = req.qsparams.get('cmd', '')
 
         # process the web interface request
 
         try:
             tmpl = rctx.templater(req)
             ctype = tmpl('mimetype', encoding=encoding.encoding)
             ctype = templater.stringify(ctype)
 
             # check read permissions non-static content
             if cmd != 'static':
                 self.check_perm(rctx, wsgireq, None)
 
             if cmd == '':
                 req.qsparams['cmd'] = tmpl.cache['default']
                 cmd = req.qsparams['cmd']
 
             # Don't enable caching if using a CSP nonce because then it wouldn't
             # be a nonce.
             if rctx.configbool('web', 'cache') and not rctx.nonce:
-                caching(self, wsgireq) # sets ETag header or raises NOT_MODIFIED
+                tag = 'W/"%d"' % self.mtime
+                if req.headers.get('If-None-Match') == tag:
+                    raise ErrorResponse(HTTP_NOT_MODIFIED)
+
+                wsgireq.headers.append((r'ETag', pycompat.sysstr(tag)))
+                res.headers['ETag'] = tag
+
             if cmd not in webcommands.__all__:
                 msg = 'no such method: %s' % cmd
                 raise ErrorResponse(HTTP_BAD_REQUEST, msg)
             elif cmd == 'file' and req.qsparams.get('style') == 'raw':
                 rctx.ctype = ctype
                 content = webcommands.rawfile(rctx, wsgireq, tmpl)
             else:
                 content = getattr(webcommands, cmd)(rctx, wsgireq, tmpl)
                 wsgireq.respond(HTTP_OK, ctype)
 
             return content
 
         except (error.LookupError, error.RepoLookupError) as err:
             wsgireq.respond(HTTP_NOT_FOUND, ctype)
             msg = pycompat.bytestr(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) as inst:
             wsgireq.respond(HTTP_SERVER_ERROR, ctype)
             return tmpl('error', error=pycompat.bytestr(inst))
         except ErrorResponse as inst:
             wsgireq.respond(inst, ctype)
             if inst.code == HTTP_NOT_MODIFIED:
                 # Not allowed to return a body on a 304
                 return ['']
             return tmpl('error', error=pycompat.bytestr(inst))
 
     def check_perm(self, rctx, req, op):
         for permhook in permhooks:
             permhook(rctx, req, op)
 
 def getwebview(repo):
     """The 'web.view' config controls changeset filter to hgweb. Possible
     values are ``served``, ``visible`` and ``all``. Default is ``served``.
     The ``served`` filter only shows changesets that can be pulled from the
     hgweb instance.  The``visible`` filter includes secret changesets but
     still excludes "hidden" one.
 
     See the repoview module for details.
 
     The option has been around undocumented since Mercurial 2.5, but no
     user ever asked about it. So we better keep it undocumented for now."""
     # experimental config: web.view
     viewconfig = repo.ui.config('web', 'view', untrusted=True)
     if viewconfig == 'all':
         return repo.unfiltered()
     elif viewconfig in repoview.filtertable:
         return repo.filtered(viewconfig)
     else:
         return repo.filtered('served')