view hgext/largefiles/basestore.py @ 36858:01f6bba64424

hgweb: remove support for POST form data (BC)

Previously, we called out to cgi.parse(), which for POST requests
parsed multipart/form-data and application/x-www-form-urlencoded
Content-Type requests for form data, combined it with query string
parameters, returned a union of the values.

As far as I know, nothing in Mercurial actually uses this mechanism
to submit data to the HTTP server. The wire protocol has its own
mechanism for passing parameters. And the web interface only does
GET requests. Removing support for parsing POST data doesn't break
any tests.

Another reason to not like this feature is that cgi.parse() may
modify the QUERY_STRING environment variable as a side-effect.
In addition, it merges both POST data and the query string into
one data structure. This prevents consumers from knowing whether
a variable came from the query string or POST data. That can matter
for some operations.

I suspect we use cgi.parse() because back when this code was
initially implemented, it was the function that was readily
available. In other words, I don't think there was conscious
choice to support POST data: we just got it because cgi.parse()
supported it.

Since nothing uses the feature and it is untested, let's remove
support for parsing POST form data. We can add it back in easily
enough if we need it in the future.

.. bc::

   Hgweb no longer reads form data in POST requests from
   multipart/form-data and application/x-www-form-urlencoded
   requests. Arguments should be specified as URL path components
   or in the query string in the URL instead.

Differential Revision: https://phab.mercurial-scm.org/D2774

# Copyright 2009-2010 Gregory P. Ward
# Copyright 2009-2010 Intelerad Medical Systems Incorporated
# Copyright 2010-2011 Fog Creek Software
# Copyright 2010-2011 Unity Technologies
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

'''base class for store implementations and store-related utility code'''
from __future__ import absolute_import

from mercurial.i18n import _

from mercurial import node, util

from . import lfutil

class StoreError(Exception):
    '''Raised when there is a problem getting files from or putting
    files to a central store.'''
    def __init__(self, filename, hash, url, detail):
        self.filename = filename
        self.hash = hash
        self.url = url
        self.detail = detail

    def longmessage(self):
        return (_("error getting id %s from url %s for file %s: %s\n") %
                 (self.hash, util.hidepassword(self.url), self.filename,
                  self.detail))

    def __str__(self):
        return "%s: %s" % (util.hidepassword(self.url), self.detail)

class basestore(object):
    def __init__(self, ui, repo, url):
        self.ui = ui
        self.repo = repo
        self.url = url

    def put(self, source, hash):
        '''Put source file into the store so it can be retrieved by hash.'''
        raise NotImplementedError('abstract method')

    def exists(self, hashes):
        '''Check to see if the store contains the given hashes. Given an
        iterable of hashes it returns a mapping from hash to bool.'''
        raise NotImplementedError('abstract method')

    def get(self, files):
        '''Get the specified largefiles from the store and write to local
        files under repo.root.  files is a list of (filename, hash)
        tuples.  Return (success, missing), lists of files successfully
        downloaded and those not found in the store.  success is a list
        of (filename, hash) tuples; missing is a list of filenames that
        we could not get.  (The detailed error message will already have
        been presented to the user, so missing is just supplied as a
        summary.)'''
        success = []
        missing = []
        ui = self.ui

        at = 0
        available = self.exists(set(hash for (_filename, hash) in files))
        for filename, hash in files:
            ui.progress(_('getting largefiles'), at, unit=_('files'),
                total=len(files))
            at += 1
            ui.note(_('getting %s:%s\n') % (filename, hash))

            if not available.get(hash):
                ui.warn(_('%s: largefile %s not available from %s\n')
                        % (filename, hash, util.hidepassword(self.url)))
                missing.append(filename)
                continue

            if self._gethash(filename, hash):
                success.append((filename, hash))
            else:
                missing.append(filename)

        ui.progress(_('getting largefiles'), None)
        return (success, missing)

    def _gethash(self, filename, hash):
        """Get file with the provided hash and store it in the local repo's
        store and in the usercache.
        filename is for informational messages only.
        """
        util.makedirs(lfutil.storepath(self.repo, ''))
        storefilename = lfutil.storepath(self.repo, hash)

        tmpname = storefilename + '.tmp'
        with util.atomictempfile(tmpname,
                createmode=self.repo.store.createmode) as tmpfile:
            try:
                gothash = self._getfile(tmpfile, filename, hash)
            except StoreError as err:
                self.ui.warn(err.longmessage())
                gothash = ""

        if gothash != hash:
            if gothash != "":
                self.ui.warn(_('%s: data corruption (expected %s, got %s)\n')
                             % (filename, hash, gothash))
            util.unlink(tmpname)
            return False

        util.rename(tmpname, storefilename)
        lfutil.linktousercache(self.repo, hash)
        return True

    def verify(self, revs, contents=False):
        '''Verify the existence (and, optionally, contents) of every big
        file revision referenced by every changeset in revs.
        Return 0 if all is well, non-zero on any errors.'''

        self.ui.status(_('searching %d changesets for largefiles\n') %
                       len(revs))
        verified = set()                # set of (filename, filenode) tuples
        filestocheck = []               # list of (cset, filename, expectedhash)
        for rev in revs:
            cctx = self.repo[rev]
            cset = "%d:%s" % (cctx.rev(), node.short(cctx.node()))

            for standin in cctx:
                filename = lfutil.splitstandin(standin)
                if filename:
                    fctx = cctx[standin]
                    key = (filename, fctx.filenode())
                    if key not in verified:
                        verified.add(key)
                        expectedhash = lfutil.readasstandin(fctx)
                        filestocheck.append((cset, filename, expectedhash))

        failed = self._verifyfiles(contents, filestocheck)

        numrevs = len(verified)
        numlfiles = len(set([fname for (fname, fnode) in verified]))
        if contents:
            self.ui.status(
                _('verified contents of %d revisions of %d largefiles\n')
                % (numrevs, numlfiles))
        else:
            self.ui.status(
                _('verified existence of %d revisions of %d largefiles\n')
                % (numrevs, numlfiles))
        return int(failed)

    def _getfile(self, tmpfile, filename, hash):
        '''Fetch one revision of one file from the store and write it
        to tmpfile.  Compute the hash of the file on-the-fly as it
        downloads and return the hash.  Close tmpfile.  Raise
        StoreError if unable to download the file (e.g. it does not
        exist in the store).'''
        raise NotImplementedError('abstract method')

    def _verifyfiles(self, contents, filestocheck):
        '''Perform the actual verification of files in the store.
        'contents' controls verification of content hash.
        'filestocheck' is list of files to check.
        Returns _true_ if any problems are found!
        '''
        raise NotImplementedError('abstract method')