Mercurial > hg
view mercurial/hgweb/common.py @ 31765:264baeef3588
show: new extension for displaying various repository data
Currently, Mercurial has a number of commands to show information. And,
there are features coming down the pipe that will introduce more
commands for showing information.
Currently, when introducing a new class of data or a view that we
wish to expose to the user, the strategy is to introduce a new command
or overload an existing command, sometimes both. For example, there is
a desire to formalize the wip/smartlog/underway/mine functionality that
many have devised. There is also a desire to introduce a "topics"
concept. Others would like views of "the current stack." In the
current model, we'd need a new command for wip/smartlog/etc (that
behaves a lot like a pre-defined alias of `hg log`). For topics,
we'd likely overload `hg topic[s]` to both display and manipulate
topics.
Adding new commands for every pre-defined query doesn't scale well
and pollutes `hg help`. Overloading commands to perform read-only and
write operations is arguably an UX anti-pattern: while having all
functionality for a given concept in one command is nice, having a
single command doing multiple discrete operations is not. Furthermore,
a user may be surprised that a command they thought was read-only
actually changes something.
We discussed this at the Mercurial 4.0 Sprint in Paris and decided that
having a single command where we could hang pre-defined views of
various data would be a good idea. Having such a command would:
* Help prevent an explosion of new query-related commands
* Create a clear separation between read and write operations
(mitigates footguns)
* Avoids overloading the meaning of commands that manipulate data
(bookmark, tag, branch, etc) (while we can't take away the
existing behavior for BC reasons, we now won't introduce this
behavior on new commands)
* Allows users to discover informational views more easily by
aggregating them in a single location
* Lowers the barrier to creating the new views (since the barrier
to creating a top-level command is relatively high)
So, this commit introduces the `hg show` command via the "show"
extension. This command accepts a positional argument of the
"view" to show. New views can be registered with a decorator. To
prove it works, we implement the "bookmarks" view, which shows a
table of bookmarks and their associated nodes.
We introduce a new style to hold everything used by `hg show`.
For our initial bookmarks view, the output varies from `hg bookmarks`:
* Padding is performed in the template itself as opposed to Python
* Revision integers are not shown
* shortest() is used to display a 5 character node by default (as
opposed to static 12 characters)
I chose to implement the "bookmarks" view first because it is simple
and shouldn't invite too much bikeshedding that detracts from the
evaluation of `hg show` itself. But there is an important point
to consider: we now have 2 ways to show a list of bookmarks. I'm not
a fan of introducing multiple ways to do very similar things. So it
might be worth discussing how we wish to tackle this issue for
bookmarks, tags, branches, MQ series, etc.
I also made the choice of explicitly declaring the default show
template not part of the standard BC guarantees. History has shown
that we make mistakes and poor choices with output formatting but
can't fix these mistakes later because random tools are parsing
output and we don't want to break these tools. Optimizing for human
consumption is one of my goals for `hg show`. So, by not covering
the formatting as part of BC, the barrier to future change is much
lower and humans benefit.
There are some improvements that can be made to formatting. For
example, we don't yet use label() in the templates. We obviously
want this for color. But I'm not sure if we should reuse the existing
log.* labels or invent new ones. I figure we can punt that to a
follow-up.
At the aforementioned Sprint, we discussed and discarded various
alternatives to `hg show`.
We considered making `hg log <view>` perform this behavior. The main
reason we can't do this is because a positional argument to `hg log`
can be a file path and if there is a conflict between a path name and
a view name, behavior is ambiguous. We could have introduced
`hg log --view` or similar, but we felt that required too much typing
(we don't want to require a command flag to show a view) and wasn't
very discoverable. Furthermore, `hg log` is optimized for showing
changelog data and there are things that `hg display` could display
that aren't changelog centric.
There were concerns about using "show" as the command name.
Some users already have a "show" alias that is similar to `hg export`.
There were also concerns that Git users adapted to `git show` would
be confused by `hg show`'s different behavior. The main difference
here is `git show` prints an `hg export` like view of the current
commit by default and `hg show` requires an argument. `git show`
can also display any Git object. `git show` does not support
displaying more complex views: just single objects. If we
implemented `hg show <hash>` or `hg show <identifier>`, `hg show`
would be a superset of `git show`. Although, I'm hesitant to do that
at this time because I view `hg show` as a higher-level querying
command and there are namespace collisions between valid identifiers
and registered views.
There is also a prefix collision with `hg showconfig`, which is an
alias of `hg config`.
We also considered `hg view`, but that is already used by the "hgk"
extension.
`hg display` was also proposed at one point. It has a prefix collision
with `hg diff`. General consensus was "show" or "view" are the best
verbs. And since "view" was taken, "show" was chosen.
There are a number of inline TODOs in this patch. Some of these
represent decisions yet to be made. Others represent features
requiring non-trivial complexity. Rather than bloat the patch or
invite additional bikeshedding, I figured I'd document future
enhancements via TODO so we can get a minimal implmentation landed.
Something is better than nothing.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Fri, 24 Mar 2017 19:19:00 -0700 |
parents | 2daeab02b4b1 |
children | 161a87ed456e |
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# hgweb/common.py - Utility functions needed by hgweb_mod and hgwebdir_mod # # Copyright 21 May 2005 - (c) 2005 Jake Edge <jake@edge2.net> # Copyright 2005, 2006 Matt Mackall <mpm@selenic.com> # # 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 uuid 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('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['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_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, message) self.code = code if headers is None: headers = [] self.headers = headers class continuereader(object): 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").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 pycompat.ossep in part or pycompat.osaltsep is not None and pycompat.osaltsep 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" fp = open(path, 'rb') data = fp.read() fp.close() 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, 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 = 'W/"%s"' % 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. """ # 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