[PATCH 2 of 2 V4] hgweb: teach archive how to handle file patterns

[Angel Ezquerra]

# HG changeset patch
# User Angel Ezquerra <angel.ezquerra at gmail.com>
# Date 1360493525 -3600
# Node ID fb655ad16f6675265da9d472ded7140a223fb283
# Parent  be3e96a41d0f4b7a1f1dd443f5261d6eeb66626a
hgweb: teach archive how to handle file patterns

The archive web command now takes into account the "file" request entry, if one
is provided.

The provided "file" is processed as a "path" pattern by default, which makes it
easy to only archive a certain file or directory. However, it is possible to
specify a different type of pattern, such as relglob by specifying it
explicitly on the query URL. Note that only "safe" patterns are allowed. Safe
patterns are 'path', 'relpath', 'glog' and 'relglob'. Other pattern types are
not allowed because they could be expensive to calculate.

With this change hgweb can to process requests such as:

1. http://mercurial.selenic.com/hg/archive/tip.zip/mercurial/templates

    This will download all files on the mercurial/templates directory as a zip
    file

2. http://mercurial.selenic.com/hg/archive/tip.tar.gz/relglob:*.py

    This will download all *.py files in the repository into a tar.gz file.

An so forth.

Note that this is a first step to add support for downloading directories from
the web interface. Currently the only way to use this feature is by manually
constructing the URL that you want to download. We will have to modify the
archiveentry map entry on the different templates so that it adds the current
folder path to the archive links.

This revision also adds a two tests for this feature to test-archive.t. The
first tests the selective archive feature and the second tests that the server
rejects "unsafe" patterns.

diff --git a/mercurial/hgweb/webcommands.py b/mercurial/hgweb/webcommands.py
--- a/mercurial/hgweb/webcommands.py
+++ b/mercurial/hgweb/webcommands.py
@@ -803,6 +803,17 @@
     if cnode == key or key == 'tip':
         arch_version = short(cnode)
     name = "%s-%s" % (reponame, arch_version)
+
+    ctx = webutil.changectx(web.repo, req)
+    pats = []
+    file = req.form.get('file', None)
+    defaultpat = 'path'
+    if file:
+        pats = [req.form['file'][0]]
+        if not scmutil.patsaresafe(pats, defaultpat):
+            msg = 'Archive pattern not allowed: %s' % pats[0]
+            raise ErrorResponse(HTTP_FORBIDDEN, msg)
+
     mimetype, artype, extension, encoding = web.archive_specs[type_]
     headers = [
         ('Content-Disposition', 'attachment; filename=%s%s' % (name, extension))
@@ -812,9 +823,9 @@
     req.headers.extend(headers)
     req.respond(HTTP_OK, mimetype)
 
-    ctx = webutil.changectx(web.repo, req)
+    matchfn = scmutil.match(ctx, pats, default=defaultpat)
     archival.archive(web.repo, req, cnode, artype, prefix=name,
-                     matchfn=scmutil.match(ctx, []),
+                     matchfn=matchfn,
                      subrepos=web.configbool("web", "archivesubrepos"))
     return []
 
diff --git a/mercurial/scmutil.py b/mercurial/scmutil.py
--- a/mercurial/scmutil.py
+++ b/mercurial/scmutil.py
@@ -682,6 +682,15 @@
 
     return l
 
+def patsaresafe(pats, defaultpattype):
+    for pat in pats:
+        pattype = defaultpattype
+        if ':' in pat:
+            pattype = pat.split(':')[0]
+        if pattype.lower() not in ('path', 'relpath', 'glog', 'relglob'):
+            return False
+    return True
+
 def expandpats(pats):
     if not util.expandglobs:
         return list(pats)
diff --git a/tests/test-archive.t b/tests/test-archive.t
--- a/tests/test-archive.t
+++ b/tests/test-archive.t
@@ -100,6 +100,13 @@
       testing: test-archive-2c0277f05ed4/baz/bletch   OK
       testing: test-archive-2c0277f05ed4/foo   OK
   No errors detected in compressed data of archive.zip.
+  $ python getarchive.py "$TIP" gz baz | gunzip | tar tf - 2>/dev/null
+  test-archive-2c0277f05ed4/baz/bletch
+
+test that we reject unsafe patterns
+
+  $ python getarchive.py "$TIP" gz relre:baz
+  HTTP Error 403: Archive pattern not allowed: relre:baz
 
   $ "$TESTDIR/killdaemons.py" $DAEMON_PIDS