hgweb: expose URL scheme and REMOTE_* attributes

hgweb: expose URL scheme and REMOTE_* attributes

These are consulted by the HTTP wire protocol handler by reading from
the env dict. Let's expose them as attributes instead.

With the wire protocol handler updates to use the new attributes, we
no longer have any consumers of the legacy wsgirequest type in the
wire protocol code (outside of a proxied call to the permissions
checker). So, we remove most references to it.

Differential Revision: https://phab.mercurial-scm.org/D2783

--- a/mercurial/hgweb/request.py	Sat Mar 10 12:31:11 2018 -0800
+++ b/mercurial/hgweb/request.py	Sat Mar 10 14:00:40 2018 -0800
@@ -129,6 +129,12 @@
     # of HTTP: Host header for hostname. This is likely what clients used.
     advertisedurl = attr.ib()
     advertisedbaseurl = attr.ib()
+    # URL scheme (part before ``://``). e.g. ``http`` or ``https``.
+    urlscheme = attr.ib()
+    # Value of REMOTE_USER, if set, or None.
+    remoteuser = attr.ib()
+    # Value of REMOTE_HOST, if set, or None.
+    remotehost = attr.ib()
     # WSGI application path.
     apppath = attr.ib()
     # List of path parts to be used for dispatch.
@@ -270,6 +276,9 @@
                          url=fullurl, baseurl=baseurl,
                          advertisedurl=advertisedfullurl,
                          advertisedbaseurl=advertisedbaseurl,
+                         urlscheme=env['wsgi.url_scheme'],
+                         remoteuser=env.get('REMOTE_USER'),
+                         remotehost=env.get('REMOTE_HOST'),
                          apppath=apppath,
                          dispatchparts=dispatchparts, dispatchpath=dispatchpath,
                          havepathinfo='PATH_INFO' in env,

--- a/mercurial/wireprotoserver.py	Sat Mar 10 12:31:11 2018 -0800
+++ b/mercurial/wireprotoserver.py	Sat Mar 10 14:00:40 2018 -0800
@@ -53,8 +53,7 @@
     return ''.join(chunks)
 
 class httpv1protocolhandler(wireprototypes.baseprotocolhandler):
-    def __init__(self, wsgireq, req, ui, checkperm):
-        self._wsgireq = wsgireq
+    def __init__(self, req, ui, checkperm):
         self._req = req
         self._ui = ui
         self._checkperm = checkperm
@@ -117,9 +116,9 @@
 
     def client(self):
         return 'remote:%s:%s:%s' % (
-            self._wsgireq.env.get('wsgi.url_scheme') or 'http',
-            urlreq.quote(self._wsgireq.env.get('REMOTE_HOST', '')),
-            urlreq.quote(self._wsgireq.env.get('REMOTE_USER', '')))
+            self._req.urlscheme,
+            urlreq.quote(self._req.remotehost or ''),
+            urlreq.quote(self._req.remoteuser or ''))
 
     def addcapabilities(self, repo, caps):
         caps.append('httpheader=%d' %
@@ -197,7 +196,7 @@
         res.setbodybytes('0\n%s\n' % b'Not Found')
         return True
 
-    proto = httpv1protocolhandler(wsgireq, req, repo.ui,
+    proto = httpv1protocolhandler(req, repo.ui,
                                   lambda perm: checkperm(rctx, wsgireq, perm))
 
     # The permissions checker should be the only thing that can raise an
@@ -205,7 +204,7 @@
     # exception here. So consider refactoring into a exception type that
     # is associated with the wire protocol.
     try:
-        _callhttp(repo, wsgireq, req, res, proto, cmd)
+        _callhttp(repo, req, res, proto, cmd)
     except hgwebcommon.ErrorResponse as e:
         for k, v in e.headers:
             res.headers[k] = v
@@ -256,7 +255,7 @@
     opts = {'level': ui.configint('server', 'zliblevel')}
     return HGTYPE, util.compengines['zlib'], opts
 
-def _callhttp(repo, wsgireq, req, res, proto, cmd):
+def _callhttp(repo, req, res, proto, cmd):
     # Avoid cycle involving hg module.
     from .hgweb import common as hgwebcommon