hgweb: raise ErrorResponses to communicate protocol errors

mercurial/hgweb/common.py

@@ -1,118 +1,120 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, incorporated herein by reference.
 
 import errno, mimetypes, os
 
 HTTP_OK = 200
 HTTP_BAD_REQUEST = 400
+HTTP_UNAUTHORIZED = 401
 HTTP_NOT_FOUND = 404
+HTTP_METHOD_NOT_ALLOWED = 405
 HTTP_SERVER_ERROR = 500
 
 class ErrorResponse(Exception):
     def __init__(self, code, message=None):
         Exception.__init__(self)
         self.code = code
         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):
     return '%d %s' % (code, _statusmessage(code))
 
 def get_mtime(repo_path):
     store_path = os.path.join(repo_path, ".hg")
     if not os.path.isdir(os.path.join(store_path, "data")):
         store_path = os.path.join(store_path, "store")
     cl_path = os.path.join(store_path, "00changelog.i")
     if os.path.exists(cl_path):
         return os.stat(cl_path).st_mtime
     else:
         return os.stat(store_path).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('/')
     path = directory
     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 ""
         path = os.path.join(path, part)
     try:
         os.stat(path)
         ct = mimetypes.guess_type(path)[0] or "text/plain"
         req.respond(HTTP_OK, ct, length = os.path.getsize(path))
         return file(path, 'rb').read()
     except TypeError:
         raise ErrorResponse(HTTP_SERVER_ERROR, 'illegal file name')
     except OSError, err:
         if err.errno == errno.ENOENT:
             raise ErrorResponse(HTTP_NOT_FOUND)
         else:
             raise ErrorResponse(HTTP_SERVER_ERROR, err.strerror)
 
 def style_map(templatepath, style):
     """Return path to mapfile for a given style.
 
     Searches mapfile in the following locations:
     1. templatepath/style/map
     2. templatepath/map-style
     3. templatepath/map
     """
     locations = style and [os.path.join(style, "map"), "map-"+style] or []
     locations.append("map")
     for location in locations:
         mapfile = os.path.join(templatepath, location)
         if os.path.isfile(mapfile):
             return mapfile
     raise RuntimeError("No hgweb templates found in %r" % templatepath)
 
 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 countgen(start=0, step=1):
     """count forever -- useful for line numbers"""
     while True:
         yield start
         start += step
 
 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 "")

mercurial/hgweb/hgweb_mod.py

@@ -1,378 +1,379 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, incorporated herein by reference.
 
 import os, mimetypes
 from mercurial.node import hex, nullid
 from mercurial.repo import RepoError
 from mercurial import mdiff, ui, hg, util, patch, hook
 from mercurial import revlog, templater, templatefilters
 from common import get_mtime, style_map, paritygen, countgen, ErrorResponse
 from common import HTTP_OK, HTTP_BAD_REQUEST, HTTP_NOT_FOUND, HTTP_SERVER_ERROR
+from common import HTTP_UNAUTHORIZED, HTTP_METHOD_NOT_ALLOWED
 from request import wsgirequest
 import webcommands, protocol, webutil
 
 perms = {
     'changegroup': 'pull',
     'changegroupsubset': 'pull',
     'unbundle': 'push',
     'stream_out': 'pull',
 }
 
 class hgweb(object):
     def __init__(self, repo, name=None):
         if isinstance(repo, str):
             parentui = ui.ui(report_untrusted=False, interactive=False)
             self.repo = hg.repository(parentui, repo)
         else:
             self.repo = repo
 
         hook.redirect(True)
         self.mtime = -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",
                                         templater.templatepath(),
                                         untrusted=False)
 
     # 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 refresh(self):
         mtime = get_mtime(self.repo.root)
         if mtime != self.mtime:
             self.mtime = mtime
             self.repo = hg.repository(self.repo.ui, self.repo.root)
             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)
             self.encoding = self.config("web", "encoding", util._encoding)
 
     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()
 
         # 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 cmd and cmd in protocol.__all__:
-            if cmd in perms and not self.check_perm(req, perms[cmd]):
-                return []
+            try:
+                if cmd in perms:
+                    self.check_perm(req, perms[cmd])
             method = getattr(protocol, cmd)
             return method(self.repo, req)
+            except ErrorResponse, inst:
+                req.respond(inst.code, protocol.HGTYPE)
+                if not inst.message:
+                    return []
+                return '0\n%s\n' % inst.message,
 
         # 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]
 
         # 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 hasattr(webcommands, cmd):
                 req.form['cmd'] = [cmd]
             else:
                 cmd = ''
 
             if args and args[0]:
                 node = args.pop(0)
                 req.form['node'] = [node]
             if args:
                 req.form['file'] = args
 
             if cmd == 'static':
                 req.form['file'] = req.form['node']
             elif 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=self.encoding)
             ctype = templater.stringify(ctype)
 
             if cmd == '':
                 req.form['cmd'] = [tmpl.cache['default']]
                 cmd = req.form['cmd'][0]
 
             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)
 
             req.write(content)
             return []
 
         except revlog.LookupError, err:
             req.respond(HTTP_NOT_FOUND, ctype)
             msg = str(err)
             if 'manifest' not in msg:
                 msg = 'revision not found: %s' % err.name
             req.write(tmpl('error', error=msg))
             return []
         except (RepoError, revlog.RevlogError), inst:
             req.respond(HTTP_SERVER_ERROR, ctype)
             req.write(tmpl('error', error=str(inst)))
             return []
         except ErrorResponse, inst:
             req.respond(inst.code, ctype)
             req.write(tmpl('error', error=inst.message))
             return []
 
     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)
         staticurl = self.config("web", "staticurl") or req.url + 'static/'
         if not staticurl.endswith('/'):
             staticurl += '/'
 
         # some functions for the templater
 
         def header(**map):
             yield tmpl('header', encoding=self.encoding, **map)
 
         def footer(**map):
             yield tmpl("footer", **map)
 
         def motd(**map):
             yield self.config("web", "motd", "")
 
         def sessionvars(**map):
             fields = []
             if 'style' in req.form:
                 style = req.form['style'][0]
                 if style != self.config('web', 'style', ''):
                     fields.append(('style', style))
 
             separator = req.url[-1] == '?' and ';' or '?'
             for name, value in fields:
                 yield dict(name=name, value=value, separator=separator)
                 separator = ';'
 
         # figure out which style to use
 
         style = self.config("web", "style", "")
         if 'style' in req.form:
             style = req.form['style'][0]
         mapfile = style_map(self.templatepath, style)
 
         if not self.reponame:
             self.reponame = (self.config("web", "name")
                              or req.env.get('REPO_NAME')
                              or req.url.strip('/') or self.repo.root)
 
         # create the templater
 
         tmpl = templater.templater(mapfile, templatefilters.filters,
                                    defaults={"url": req.url,
                                              "staticurl": staticurl,
                                              "urlbase": urlbase,
                                              "repo": self.reponame,
                                              "header": header,
                                              "footer": footer,
                                              "motd": motd,
                                              "sessionvars": sessionvars
                                             })
         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}
 
     def listfilediffs(self, tmpl, files, changeset):
         for f in files[:self.maxfiles]:
             yield tmpl("filedifflink", node=hex(changeset), file=f)
         if len(files) > self.maxfiles:
             yield tmpl("fileellipses")
 
     def diff(self, tmpl, node1, node2, files):
         def filterfiles(filters, files):
             l = [x for x in files if x in filters]
 
             for t in filters:
                 if t and t[-1] != os.sep:
                     t += os.sep
                 l += [x for x in files if x.startswith(t)]
             return l
 
         parity = paritygen(self.stripecount)
         def diffblock(diff, f, fn):
             yield tmpl("diffblock",
                        lines=prettyprintlines(diff),
                        parity=parity.next(),
                        file=f,
                        filenode=hex(fn or nullid))
 
         blockcount = countgen()
         def prettyprintlines(diff):
             blockno = blockcount.next()
             for lineno, l in enumerate(diff.splitlines(1)):
                 if blockno == 0:
                     lineno = lineno + 1
                 else:
                     lineno = "%d.%d" % (blockno, lineno + 1)
                 if l.startswith('+'):
                     ltype = "difflineplus"
                 elif l.startswith('-'):
                     ltype = "difflineminus"
                 elif l.startswith('@'):
                     ltype = "difflineat"
                 else:
                     ltype = "diffline"
                 yield tmpl(ltype,
                            line=l,
                            lineid="l%s" % lineno,
                            linenumber="% 8s" % lineno)
 
         r = self.repo
         c1 = r[node1]
         c2 = r[node2]
         date1 = util.datestr(c1.date())
         date2 = util.datestr(c2.date())
 
         modified, added, removed, deleted, unknown = r.status(node1, node2)[:5]
         if files:
             modified, added, removed = map(lambda x: filterfiles(files, x),
                                            (modified, added, removed))
 
         diffopts = patch.diffopts(self.repo.ui, untrusted=True)
         for f in modified:
             to = c1.filectx(f).data()
             tn = c2.filectx(f).data()
             yield diffblock(mdiff.unidiff(to, date1, tn, date2, f, f,
                                           opts=diffopts), f, tn)
         for f in added:
             to = None
             tn = c2.filectx(f).data()
             yield diffblock(mdiff.unidiff(to, date1, tn, date2, f, f,
                                           opts=diffopts), f, tn)
         for f in removed:
             to = c1.filectx(f).data()
             tn = None
             yield diffblock(mdiff.unidiff(to, date1, tn, date2, f, f,
                                           opts=diffopts), f, tn)
 
     archive_specs = {
         'bz2': ('application/x-tar', 'tbz2', '.tar.bz2', None),
         'gz': ('application/x-tar', 'tgz', '.tar.gz', None),
         'zip': ('application/zip', 'zip', '.zip', None),
         }
 
     def check_perm(self, req, op):
         '''Check permission for operation based on request data (including
         authentication info. Return true if op allowed, else false.'''
 
-        def error(status, message):
-            req.respond(status, protocol.HGTYPE)
-            req.write('0\n%s\n' % message)
-
-        if op == 'pull':
-            return self.allowpull
+        if op == 'pull' and not self.allowpull:
+            raise ErrorResponse(HTTP_OK, '')
+        elif op == 'pull':
+            return
 
         # enforce that you can only push using POST requests
         if req.env['REQUEST_METHOD'] != 'POST':
-            error('405 Method Not Allowed', 'push requires POST request')
-            return False
+            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 self.configbool('web', 'push_ssl', True) and scheme != 'https':
-            error(HTTP_OK, 'ssl required')
-            return False
+            raise ErrorResponse(HTTP_OK, 'ssl required')
 
         user = req.env.get('REMOTE_USER')
 
         deny = self.configlist('web', 'deny_push')
         if deny and (not user or deny == ['*'] or user in deny):
-            error('401 Unauthorized', 'push not authorized')
-            return False
+            raise ErrorResponse(HTTP_UNAUTHORIZED, 'push not authorized')
 
         allow = self.configlist('web', 'allow_push')
         result = allow and (allow == ['*'] or user in allow)
         if not result:
-            error('401 Unauthorized', 'push not authorized')
-
-        return result
+            raise ErrorResponse(HTTP_UNAUTHORIZED, 'push not authorized')

mercurial/hgweb/protocol.py

@@ -1,200 +1,196 b''
 #
 # 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, incorporated herein by reference.
 
 import cStringIO, zlib, tempfile, errno, os, sys
 from mercurial import util, streamclone
 from mercurial.node import bin, hex
 from mercurial import changegroup as changegroupmod
 from common import HTTP_OK, HTTP_NOT_FOUND, HTTP_SERVER_ERROR
 
 # __all__ is populated with the allowed commands. Be sure to add to it if
 # you're adding a new command, or the new command won't work.
 
 __all__ = [
    'lookup', 'heads', 'branches', 'between', 'changegroup',
    'changegroupsubset', 'capabilities', 'unbundle', 'stream_out',
 ]
 
 HGTYPE = 'application/mercurial-0.1'
 
 def lookup(repo, req):
     try:
         r = hex(repo.lookup(req.form['key'][0]))
         success = 1
     except Exception,inst:
         r = str(inst)
         success = 0
     resp = "%s %s\n" % (success, r)
     req.respond(HTTP_OK, HGTYPE, length=len(resp))
     yield resp
 
 def heads(repo, req):
     resp = " ".join(map(hex, repo.heads())) + "\n"
     req.respond(HTTP_OK, HGTYPE, length=len(resp))
     yield resp
 
 def branches(repo, req):
     nodes = []
     if 'nodes' in req.form:
         nodes = map(bin, req.form['nodes'][0].split(" "))
     resp = cStringIO.StringIO()
     for b in repo.branches(nodes):
         resp.write(" ".join(map(hex, b)) + "\n")
     resp = resp.getvalue()
     req.respond(HTTP_OK, HGTYPE, length=len(resp))
     yield resp
 
 def between(repo, req):
     if 'pairs' in req.form:
         pairs = [map(bin, p.split("-"))
                  for p in req.form['pairs'][0].split(" ")]
     resp = cStringIO.StringIO()
     for b in repo.between(pairs):
         resp.write(" ".join(map(hex, b)) + "\n")
     resp = resp.getvalue()
     req.respond(HTTP_OK, HGTYPE, length=len(resp))
     yield resp
 
 def changegroup(repo, req):
     req.respond(HTTP_OK, HGTYPE)
     nodes = []
 
     if 'roots' in req.form:
         nodes = map(bin, req.form['roots'][0].split(" "))
 
     z = zlib.compressobj()
     f = repo.changegroup(nodes, 'serve')
     while 1:
         chunk = f.read(4096)
         if not chunk:
             break
         yield z.compress(chunk)
 
     yield z.flush()
 
 def changegroupsubset(repo, req):
     req.respond(HTTP_OK, HGTYPE)
     bases = []
     heads = []
 
     if 'bases' in req.form:
         bases = [bin(x) for x in req.form['bases'][0].split(' ')]
     if 'heads' in req.form:
         heads = [bin(x) for x in req.form['heads'][0].split(' ')]
 
     z = zlib.compressobj()
     f = repo.changegroupsubset(bases, heads, 'serve')
     while 1:
         chunk = f.read(4096)
         if not chunk:
             break
         yield z.compress(chunk)
 
     yield z.flush()
 
 def capabilities(repo, req):
     caps = ['lookup', 'changegroupsubset']
     if repo.ui.configbool('server', 'uncompressed', untrusted=True):
         caps.append('stream=%d' % repo.changelog.version)
     if changegroupmod.bundlepriority:
         caps.append('unbundle=%s' % ','.join(changegroupmod.bundlepriority))
     rsp = ' '.join(caps)
     req.respond(HTTP_OK, HGTYPE, length=len(rsp))
     yield rsp
 
 def unbundle(repo, req):
 
-    errorfmt = '0\n%s\n'
     proto = req.env.get('wsgi.url_scheme') or 'http'
     their_heads = req.form['heads'][0].split(' ')
 
     def check_heads():
         heads = map(hex, repo.heads())
         return their_heads == [hex('force')] or their_heads == heads
 
     # fail early if possible
     if not check_heads():
         length = int(req.env.get('CONTENT_LENGTH', 0))
         for s in util.filechunkiter(req, limit=length):
             # drain incoming bundle, else client will not see
             # response when run outside cgi script
             pass
-        req.respond(HTTP_OK, HGTYPE)
-        return errorfmt % 'unsynced changes',
-
-    req.respond(HTTP_OK, HGTYPE)
+        raise ErrorResponse(HTTP_OK, 'unsynced changes')
 
     # do not lock repo until all changegroup data is
     # streamed. save to temporary file.
 
     fd, tempname = tempfile.mkstemp(prefix='hg-unbundle-')
     fp = os.fdopen(fd, 'wb+')
     try:
         length = int(req.env['CONTENT_LENGTH'])
         for s in util.filechunkiter(req, limit=length):
             fp.write(s)
 
         try:
             lock = repo.lock()
             try:
                 if not check_heads():
-                    return errorfmt % 'unsynced changes',
+                    raise ErrorResponse(HTTP_OK, 'unsynced changes')
 
                 fp.seek(0)
                 header = fp.read(6)
                 if header.startswith('HG') and not header.startswith('HG10'):
                     raise ValueError('unknown bundle version')
                 elif header not in changegroupmod.bundletypes:
                     raise ValueError('unknown bundle compression type')
                 gen = changegroupmod.unbundle(header, fp)
 
                 # send addchangegroup output to client
 
                 oldio = sys.stdout, sys.stderr
                 sys.stderr = sys.stdout = cStringIO.StringIO()
 
                 try:
                     url = 'remote:%s:%s' % (proto,
                                             req.env.get('REMOTE_HOST', ''))
                     try:
                         ret = repo.addchangegroup(gen, 'serve', url)
                     except util.Abort, inst:
                         sys.stdout.write("abort: %s\n" % inst)
                         ret = 0
                 finally:
                     val = sys.stdout.getvalue()
                     sys.stdout, sys.stderr = oldio
+                req.respond(HTTP_OK, HGTYPE)
                 return '%d\n%s' % (ret, val),
             finally:
                 del lock
         except ValueError, inst:
-            return errorfmt % inst,
+            raise ErrorResponse(HTTP_OK, inst)
         except (OSError, IOError), inst:
             filename = getattr(inst, 'filename', '')
             # Don't send our filesystem layout to the client
             if filename.startswith(repo.root):
                 filename = filename[len(repo.root)+1:]
             else:
                 filename = ''
             error = getattr(inst, 'strerror', 'Unknown error')
             if inst.errno == errno.ENOENT:
                 code = HTTP_NOT_FOUND
             else:
                 code = HTTP_SERVER_ERROR
-            req.respond(code)
-            return '0\n%s: %s\n' % (error, filename),
+            raise ErrorResponse(code, '%s: %s' % (error, filename))
     finally:
         fp.close()
         os.unlink(tempname)
 
 def stream_out(repo, req):
     req.respond(HTTP_OK, HGTYPE)
     try:
         for chunk in streamclone.stream_out(repo, untrusted=True):
             yield chunk
     except streamclone.StreamException, inst:
         yield str(inst)