Log in
Forgot your password?
Virtual Hosting Services
Zope comes with two objects that help you do virtual hosting, SiteRoot and Virtual Host Monster. Virtual hosting is a way to serve many web sites with one Zope server.
SiteRoots are an artifact of an older generation of Zope virtual hosting services that are only retained in current Zope versions for backwards-compatibility purposes. They are not documented in this book because they are somewhat "dangerous" for new users, as they have the capability of temporarily "locking you out" of your Zope instance if you configure them improperly. Luckily, we have Virtual Host Monsters, which do everything that SiteRoots do and more without any of the dangerous side effects of SiteRoots. If you want to do virtual hosting in Zope, you should almost certainly be using a Virtual Host Monster.
Anonymous User - Feb. 13, 2004 7:27 pm: Hint: The virtual host monster will become confused if you have a site-root object somewhere further up the heirarchy. I suggest that you eliminate all site-root objects from your system.
Anonymous User - May 2, 2004 1:52 am: What does above Anonymous User mean by "site-root object somewhere further up the heirarchy"? Surely not that I should remove my site-root. So then what "site-root" is he referring to?
Anonymous User - May 17, 2004 1:58 am: There is another method of tricking Zope into thinking that a child folder is actually the site root by the use of the "site-root" object. The suggestion was of course to remove these specific special objects, NOT your actual site root ;)
Virtual Host Monster
Zope objects need to generate their own URLs from time to time. For instance, when a Zope object has its "absolute_url" method called, it needs to return a URL which is appropriate for itself. This URL typically contains a hostname, a port, and a path. In a "default" Zope installation, this hostname, port, and path is typically what you want. But when it comes time to serve multiple websites out of a single Zope instance, each with their own "top-level" domain name, or when it comes time to integrate a Zope Folder within an existing website using Apache or another webserver, the URLs that Zope objects generate need to change to suit your configuration.
A Virtual Host Monster's only job is to change the URLs which
your Zope objects generate. This allows you to customize the
URLs that are displayed within your Zope application, allowing
an object to have a different URL when accessed in a different
way. This is most typically useful, for example, when you wish
to "publish" the contents of a single Zope Folder
(e.g. /FooFolder) as a URL that does not actually contain this
Folder's name (e.g as the hostname http://www.foofolder.com/).
Anonymous User - Dec. 6, 2003 6:58 am: remember to use catalogpathaware instead of catalogaware in your objext, otherwise you'll have path problems with VHM
The Virtual Host Monster performs this job by intercepting and deciphering information passed to Zope within special path elements encoded in the URLs of requests which come in to Zope. If these special path elements are absent in the URLs of requests to the Zope server, the Virtual Host Monster does nothing. If they are present, however, the Virtual Host Monster deciphers the information passed in via these path elements and causes your Zope objects to generate a URL that is different from their "default" URL.
The Zope values which are effected by the presence of a Virtual Host Monster include REQUEST variables starting with URL or BASE (such as URL1, BASE2, URLPATH0), and the absolute_url() methods of objects.
Virtual Host Monster configuration can be complicated, because it requires that you rewrite URLs "on the way in" to Zope. In order for the special path elements to be introduced into the URL of the request sent to Zope, a front-end URL "rewriting" tool needs to be employed. Virtual Host Monster comes with a simple rewriting tool in the form of its Mappings view, or alternately you can use Apache or another webserver to rewrite URLs of requests destined to Zope for you.
Where to Put a Virtual Host Monster And What To Name It
A single Virtual Host Monster in your Zope root can handle all
of your virtual hosting needs. It doesn't matter what id you
give it, as long as nothing else in your site has the same
id.
Chirael - Mar. 27, 2004 4:01 am: Um, where does one GET a Virtual Host Monster? Is it a Zope "product" which requires a separate installation? Does it come built-in with Zope "out of the package"? If so, how do you make it appear in the right spot--is it one of the built-in types in the "Add" list? There needs to be more explanation of what the VHM *is*, how you *get it*, and how you make it appear where it needs to be prior to configuration. This page at the moment just jumps right into configuration, which is pretty confusing to a newbie IMO.
Anonymous User - Apr. 6, 2004 12:14 pm: In the ZMI, go to the "Root Folder", and click on the pull down menu. You'll see "Virtual Host Monster" in there. Selecting this will bring you to a page that asks for an ID, (which might as well be auto generated imho).
Anonymous User - Apr. 15, 2004 10:15 pm: How about for Linux from command shell? how does one add or modify a VHM??
ashugg - Feb. 3, 2005 11:02 pm: $ lynx http://server:port/manage_addProduct/SiteAccess/manage_addVirtaulHostMonsterForm =)
Anonymous User - Aug. 27, 2005 1:55 pm: maybe it was just me and my installation, but i couldnt for the life of me get this to work and that was because zope already had a preinstalled virtual host monster which the docs didnt seem to mention, or at least I couldnt find it. This commenting within the documentation confused me.
Special VHM Path Elements VirtualHostBase and VirtualHostRoot
A Virtual Host Monster doesn't do anything unless it sees one of the following special path elements in a URL:
-
VirtualHostBase - if a VirtualHostMonster "sees" this name in the incoming URL, it causes Zope objects to generate URLs with a potentially different protocol, a potentially different hostname, and a potentially different port number.
-
VirtualHostRoot - if a VirtualHostMonster "sees" this name in the incoming URL, it causes Zope objects to generate URLs which have a potentially different "path root"
VirtualHostBase
The VirtualHostBase declaration is typically found at the
beginning of an incoming URL. A Virtual Host Monster will
intercept two path elements following this name and will use
them to compose a new protocol, hostname, and port number.
The two path elements which must follow a VirtualHostBase
declaration are protocol and hostname:portnumber. They
must be separated by a single slash. The colon and
portnumber parts of the second element are optional, and if
they don't exist, the Virtual Host Monster will not change
the port number of Zope-generated URLs.
If a VHM is installed in the root folder, and a request comes in to your Zope with the URL: 'http://zopeserver:8080/VirtualHostBase/http/www.buystuff.com' URLs generated by Zope objects will start with 'http://buystuff.com:8080'. If a VHM is installed in the root folder, and a request comes in to your Zope with the URL: 'http://zopeserver:8080/VirtualHostBase/http/www.buystuff.com:80' URLs generated by Zope objects will start with 'http://buystuff.com' (port 80 is the default port number so it is left out). If a VHM is installed in the root folder, and a request comes in to your Zope with the URL: 'http://zopeserver:8080/VirtualHostBase/https/www.buystuff.com:443' URLs generated by Zope objects will start with 'https://buystuff.com/'. (port 443 is the default https port number, so it is left off.
One thing to note when reading the examples above is that if
your Zope is running on a port number like 8080, and you
want generated URLs to not include this port number and
instead be served on the standard HTTP port (80), you must
specifically include the default port 80 within the
VirtualHostBase declaration, e.g.
/VirtualHostBase/http/www.buystuff.com:80. If you don't
specify the :80, your Zope's HTTP port number will be used
(which is likely not what you want).
VirtualHostRoot
The VirtualHostRoot declaration is typically found near
the end of an incoming URL. A Virtual Host Monster will
gather up all path elements which precede and follow the
VirtualHostRoot name, traverse the Zope object hierarchy
with these elements, and publish the object it finds with
the path rewritten to the path element(s) which follow(s)
the VirtualHostRoot name.
This is easier to understand by example. For a URL
/a/b/c/VirtualHostRoot/d, the Virtual Host Monster will
traverse "a/b/c/d" and then generate a URL with path /d.
If a VHM is installed in the root folder, and a request comes in to your Zope with the URL: 'http://zopeserver:8080/Folder/VirtualHostRoot/ The object 'Folder' will be traversed to and published, URLs generated by Zope will start with 'http://zopeserver:8080/', and when they are visited, they will be considered relative to 'Folder'. If a VHM is installed in the root folder, and a request comes in to your Zope with the URL: 'http://zopeserver:8080/HomeFolder/VirtualHostRoot/Chris The object '/Folder/Chris' will be traversed to and published, URLs generated by Zope will start with 'http://zopeserver:8080/Chris', and when they are visited, they will be considered relative to '/HomeFolder/Chris'.
dig - Aug. 22, 2004 4:15 pm: - The object '/Folder/Chris' will be traversed to and ... + The object '/HomeFolder/Chris' will be traversed to and ...
Using VirtualHostRoot and VirtualHostBase Together
The most common sort of virtual hosting setup is one in which
you create a Folder in your Zope root for each domain that you
want to serve. For instance the site http://www.buystuff.com
is served from a Folder in the Zope root named /buystuff while
the site http://www.mycause.org is served from a Folder in the
Zope root named /mycause. In order to do this, you need to
generate URLs that have both VirtualHostBase and
VirtualHostRoot in them.
To access /mycause as http://www.mycause.org/, you would cause Zope to be visited via the following URL:
/VirtualHostBase/http/www.mycause.org:80/mycause/VirtualHostRoot/
In the same Zope instance, to access /buystuff as http://www.buystuff.com/, you would cause Zope to be visited via the following URL:
/VirtualHostBase/http/www.buystuff.com:80/buystuff/VirtualHostRoot/
Testing a Virtual Host Monster
Set up a Zope on your local machine that listens on HTTP port 8080 for incoming requests.
Visit the root folder, and select Virtual Host Monster from
the Add list. Fill in the id on the add form as VHM and
click Add.
Create a Folder in your Zope root named vhm_test. Within the
newly-created vhm_test folder, create a DTML Method named
index_html and enter the following into its body:
<html>
<body>
<table border="1">
<tr>
<td>Absolute URL</td>
<td><dtml-var absolute_url></td>
</tr>
<tr>
<td>URL0</td>
<td><dtml-var URL0></td>
</tr>
<tr>
<td>URL1</td>
<td><dtml-var URL1></td>
</tr>
</table>
</body>
</html>
View the DTML Method by clicking on its View tab, and you will see something like the following:
Absolute URL http://localhost:8080/vhm_test URL0 http://localhost:8080/vhm_test/index_html URL1 http://localhost:8080/vhm_test
Now visit the URL http://localhost:8080/vhm_test. You will be
presented with something that looks almost exactly the same.
Now visit the URL
http://localhost:8080/VirtualHostBase/http/zope.com:80/vhm_test.
You will be presented with something that looks much like this:
Absolute URL http://zope.com/vhm_test URL0 http://zope.com/vhm_test/index_html URL1 http://zope.com/vhm_test
Note that the URLs that Zope is generating have changed.
Instead of using localhost:8080 for the hostname and path,
we've instructed Zope, through the use of a VirtualHostBase
directive to use zope.com as the hostname. No port is shown
because we've told Zope that we want to generate URLs with a
port number of 80, which is the default http port.
Now visit the URL
http://localhost:8080/VirtualHostBase/http/zope.com:80/vhm_test/VirtualHostRoot/.
You will be presented with something that looks much like this:
Absolute URL http://zope.com URL0 http://zope.com/index_html URL1 http://zope.com
Note that we're now publishing the vhm_test folder as if it
were the root folder of a domain named zope.com. We did this
by appending a VirtualHostRoot directive to the incoming URL,
which essentially says "traverse to the vhm_root folder as if it
were the root of the site."
Arranginging for Incoming URLs to be Rewritten
At this point, you're probably wondering just how in the world
any of this helps you. You're certainly not going to ask
people to use their browser to visit a URL like
http://yourserver.com//VirtualHostBase/http/zope.com/vhm_test/VirtualHostRoot/
just so your Zope-generated URLs will be "right". That would
defeat the pupose of virtual hosting entirely. The answer is:
don't ask humans to do it, ask your computer to do it. There
are two common (but mutually excusive) ways to accomplish
this: via the VirtualHostMonster Mappings tab and via Apache
"rewrite rules" (or your webserver's facility to do the same
thing if you don't use Apache). Be warned: use either one of
these facilities or the other but not both or very strange
things may start to happen. We give examples of using both
facilities below.
Anonymous User - May 10, 2004 9:57 am: http://yourserver.com//VirtualHostBase should be http://yourserver.com/VirtualHostBase (only one slash)
Anonymous User - Jan. 5, 2005 8:41 am: I suggest moving this point to the `abstact' section instead of prepending "At this this point you're probably wonderning ...". This a software reference not a book by Diderot ;)
Anonymous User - Mar. 2, 2005 4:11 am: I agree. The structure of this documentation is almost an invitation *not* to use virtual hosting. Why not just follow the 'natural' path of a request: The user agent asks for http://www.foo.com - there's no resource resolving this request, so Apache or Zope have to do the following mapping (blabla) to 'feed' a strange beast called VirtualHostMonster which is set up like this (further blabla). Otherwise, the innocent reader is deliberately kept in a state of skepticism for almost the entire document. ;-)
Anonymous User - July 10, 2005 8:27 pm: very good suggestion I always be confused by the VHM. 1:user type http://www.foo.com 2:HOW: http://www.foo.com ==> http://yourserver.com/... 2.1 Apache map:www.foo.com==>http://yourserver.com/... 2.2 VHM map:www.foo.com==>http://yourserver.com/... 3:VHM: .....
Virtual Host Monster Mappings Tab
Use the Virtual Host Monster's Mappings tab to cause your URLs to be rewritten if:
- You run a "bare" Zope without a front-end webserver like Apache.
- You have one or more folders in your Zope that you'd like to publish as "http://some.hostname.com/" instead of "http://hostname.com/a/folder".
The lines entered into the Mappings tab are in the form
Anonymous User - Feb. 18, 2005 1:25 pm: are in the form??? examples? please?
The best way to explain how to use the Mappings tab is by
example. Assuming you've added a Virtual Host Monster
object in your root folder on a Zope running on localhost
on port 8080, create an alias in your local system's hosts
file (in /etc/hosts on UNIX and in
c:\WINNT\system32\drivers\etc\hosts on Windows) that looks
like this:
127.0.0.1 www.example.com
This causes your local machine to contact itself when a
hostname of wwww.example.com is encountered. For the sake
of this example, we're going to want to contact Zope via the
hostname www.example.com through a browser (also on your
local host) and this makes it possible.
Anonymous User - Dec. 6, 2004 10:38 am: - wwww.example.com + www.example.com
Then visit the VHM in the root folder and click on its Mappings tab. On a line by itself enter the following:
www.example.com:8080/vhm_test
This will cause the vhm_test folder to be published when
we visit http://www.example.com:8080. Visit
http://www.example.com:8080. You will see:
Absolute URL http://www.example.com:8080 URL0 http://www.example.com:8080/index_html URL1 http://www.example.com:8080
In the "real world" this means that you are "publishing" the
vhm_test folder as http://www.example.com:8080.
You can match multiple subdomains by putting "." in front of the host name in the mapping rule. For example, ".buystuff.com" will match "my.buystuff.com", "zoom.buystuff.com", etc. If an exact match exists, it is used instead of a wildcard match.
Note that it is not possible to rewrite the port part
(by default, 8080) of the URL this way. To change the
port Zope is listening on, you will have to configure
Zopes' start parameter or use Apache rewriting.
Apache Rewrite Rules
If you use Apache in front of Zope, instead of using the Mappings tab, you should use Apache's rewrite rule functionality to rewrite URLs in to Zope. The way this works is straightforward: Apache listens on its "normal" port, typically port 80. At the same time, Zope's web server (on the same host or on another host) listens on a different port (typically 8080). Apache accepts requests on its listening port. A virtual host declaration in Apache's configuration tells Apache to apply the contained directives to the specified virtual host.
Using Apache's rewrite rule functionality requires
that the mod_rewrite and mod_proxy Apache modules
be enabled. This can for instance be done by
configuring Apache with the --enable-modules="rewrite
proxy" flag during compile time or by loading the
corresponding shared modules. If you are using the new
Apache 2 series, you will also have to include the
mod_proxy_http module. See the
Apache documentation for
details.
Anonymous User - Mar. 27, 2004 3:33 am: The Apache link could be more specific to be helpful, such as http://httpd.apache.org/docs/mod/index.html
Chirael - Mar. 27, 2004 3:38 am: You might also want to tell someone how to verify whether these modules are already installed. Yes, you shouldn't get into detail since that's in the Apache docs, but you're going to the trouble of telling them which rewrite rules to use, and that's in the docs too, so you're already duplicating the Apache docs somewhat. Anyway, I would suggest something like the following: "You likely already have one or more of these modules enabled, and you would typically check by seeing what is enabled in the 'LoadModule' section of httpd.conf. See the Apache documentation for details."
cbc - June 3, 2004 6:44 pm: You can tell what modules are already *statically* loaded with the "httpd -l" command.
After you've got Apache configured with mod_rewrite
and mod_proxy (and, depending on your Apache version,
mod_proxy_http), you can start configuring Apache's
config file and Zope for the following example.
Assuming you've added a Virtual Host Monster object in
your root folder on a Zope running on localhost on
port 8080, create an alias in your local system's
hosts file (in /etc/hosts on UNIX and in
c:\WINNT\system32\drivers\etc\hosts on Windows) that
looks like this:
127.0.0.1 www.example.com
This causes your local machine to contact itself when a
hostname of wwww.example.com is encountered. For the sake
of this example, we're going to want to contact Zope via the
hostname www.example.com through a browser (also on your
local host) and this makes it possible.
Anonymous User - Apr. 3, 2004 9:11 am: On MacOS X Server 10.3, it's easy to add virtual host with 'Server Admin.app'. This application can make and maintain virtual host , access log, etc. If you make virtual host named 'www.exsample.com', its .config file named '0000_any_80_www.example.com.config' is made at /etc/httpd/sites/. Then, open this file and add following two lines just before </VirtualHost>. RewriteEngine On RewriteRule ^/(.*) http://localhost:8080/......
Anonymous User - Dec. 6, 2004 10:41 am: - wwww.example.com + www.example.com
Now, assuming you've got Apache running on port 80 and Zope
running on port 8080 on your local machine, and assuming
that you want to serve the folder named vhm_test in Zope
as www.example.com and, add the following to your Apache's
httpd.conf file and restart your Apache process:
NameVirtualHost * <VirtualHost *> ServerName www.example.com RewriteEngine On RewriteRule ^/(.*) http://127.0.0.1:8080/VirtualHostBase/http/www.example.com:80/vhm_test/VirtualHostRoot/$1 [L,P] </VirtualHost>
Anonymous User - Nov. 9, 2003 7:35 pm: How about some artificial line breaks in here? On a 12-inch iBook this page is about 40% wider than the display, requiring much side-scrolling that reminds me of Donkey Kong on the Nintendo....
Anonymous User - Feb. 16, 2004 11:40 pm: Really? It's not a problem on a 23-inch Apple Cinema Display :)
Anonymous User - Mar. 14, 2004 5:00 am: If you are using https (with Apache listening on port 443) you should add to the VirtualHost definition: SSLProxyEngine on. So the Apache Virtual Host section becomes: NameVirtualHost *:443 <VirtualHost *:443> ServerName www.example.com SSLProxyEngine on RewriteEngine On RewriteRule ^/(.*) http://127.0.0.1:8080/VirtualHostBase/https/www.example.com:443/vhm_test/VirtualHostRoot/$1 [L,P] </VirtualHost>
Chirael - Mar. 27, 2004 3:55 am: Actually, instead of artificial line breaks, shouldn't there be a note about that long line needs to stay as one long line?
When you visit http://www.example.com in your browser, you
will see:
Absolute URL http://www.example.com URL0 http://www.example.com/index_html URL1 http://www.example.com
This page is being served by Apache, but the results are
coming from Zope. Requests come in to Apache with "normal"
URLs (e.g. http://www.example.com). The VirtualHost
stanza in Apache's httpd.conf causes the request URL to be
rewritten (e.g. to
http://127.0.0.1:8080/VirtualHostBase/http/www.example.com:80/vhm_test/VirtualHostRoot/).
Apache then calls the rewritten URL, and returns the result.
See the Apache Documentation for more information on the subject of rewrite rules.
"Inside-Out" Virtual Hosting
Another use for virtual hosting is to make Zope appear to be
part of a site controlled by another server. For example, Zope
might only serve the contents of
http://www.mycause.org/dynamic_stuff, while Apache or
another webserver serves files via
http://www.mycause.org/. To accomplish this, you want to add
"dynamic_stuff" to the start of all Zope-generated URLs.
Anonymous User - Nov. 7, 2004 9:19 pm:
It took me quite a lot of time to figure out how to write a CORRECT RewriteRule for apache so I contribute
this to save yours:
When testing a wrong rule with Plone and Silva an html page came out, textual information was more or less as
expected but images, and formating (i.e. CSS info) were missing since respective URLs where wrong. So if you
see something similar make sure you inspect the rewrite_rule log in apache log directory (well, that is if
you have added
RewriteLog "logs/rewrite_rule_log"
RewriteLogLevel [Number]
after the
RewriteEngine On
directive in httpd.conf in the example above)
so the correct rule is:
RewriteRule ^/dynamic_stuff/(.*)
http://12.0.0.1:8080/VirtualHostBase/http/www.mycause.org:80/a/VirtualHostRoot/_vh_dynamic_stuff/$1 [P]
given that /a under Zope root will serve http://www.mycause.org/dynamic_stuff/
For the record: my mistake was omitting "(.*)" .... :-(
Anonymous User - Nov. 7, 2004 9:25 pm:
RewriteLogLevel [Number]
should read
RewriteLogLevel 9
for debugging purposes while normally (no rewrite info is required) one could use:
RewriteLogLevel 0
or comment it out
If you insert VirtualHostRoot, followed by one or more path
elements that start with _vh_, then these elements will be
ignored during traversal and then added (without the _vh_)
to the start of generated URLs. For instance, a request for
"/a/VirtualHostRoot/_vh_z/" will traverse "a" and then
generate URLs that start with /z.
In our example, you would have the main server send requests for http://www.mycause.org/dynamic_stuff/anything to Zope, rewritten as /VirtualHostRoot/_vh_dynamic_stuff/anything.