HelpOnConfiguration

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Configuration of MoinMoin

1. Configuration of a single wiki

If you run a single wiki only, you should not use the file farmconfig.py, remove it from your configuration directory. Moin will then use a built-in list [("wikiconfig", r".*")] that matches every request to the config file wikiconfig.py.

A single MoinMoin wiki is configured by changing the wikiconfig.py file, which normally sits besides your moin.cgi driver script. wikiconfig.py is imported by the MoinMoin main code early in a request cycle and is found because the current directory (i.e. that of moin.cgi) is part of the Python system path. Consequently, wikiconfig.py can sit anywhere in your PYTHONPATH.

# -*- coding: iso-8859-1 -*-
# wikiconfig.py:
from MoinMoin.multiconfig import DefaultConfig
class Config(DefaultConfig):
    sitename = u'MyWiki'   # u means that it will be converted to Unicode
    interwikiname = 'MyWiki'
    data_dir = '/where/ever/mywiki/data/'
    underlay_dir = '/where/ever/mywiki/underlay/'
    # ...

Explanation:

• first we import moin's internal default configuration - copy this line "as is" to your configuration file.
• then we define a new configuration class called "Config" and inherit all settings from the default configuration we imported - also copy this line "as is". When handling requests, moin internally will create an object of this class "Config".
• after that we have to indent every line belonging to our "Config" class. THIS IS IMPORTANT - wrong indentation can make your configuration fail or do things you do not want. Use 4 blanks per level of indentation, do not use TABs.

• now we override the default config's sitename ("An unnamed moin wiki") - remember: we inherited everything from the default config class - by the sitename we want to use ("MyWiki").

• As the sitename (and also some other settings) could contain non-ASCII characters (used in languages other than English) it must be Unicode. We prefix an encoded string with an "u" character to get that string automatically decoded to Unicode when the config is loaded. The correct encoding of the config file must be given at top of the file and must be a encoding recognized by Python (like iso-8859-1, iso-8859-15, utf-8 etc.) - and of course you must not mix different encodings in your config.

• of course we also want to override the data_dir (every wiki needs its own!) and underlay_dir (can be shared).

• anything we do not override simply stays at moin's internal defaults which we inherited from DefaultConfig.

2. Configuration of multiple wikis

The moinmoin wiki engine is capable of handling multiple wikis using a single installation, a single set of configuration files and a single server process. Especially for persistent environments like twisted, this is necessary, because the twisted server will permanently run on a specific IP address and TCP port number. So for virtual hosting of multiple domains (wikis) on the same IP and port, we need the wiki engine to permanently load multiple configs at the same time and choose the right of them when handling a request for a specific URL.

To be able to choose the right config, moin uses config variable wikis located in the file farmconfig.py - it simply contains a list of pairs (wikiname, url-regex). When processing a request for some URL, moin searches through this list and tries to match the url-regex against the current URL. If it doesn't match, it simply proceeds to the next pair. If it does match, moin loads a configuration file named <wikiname>.py (usually from the same directory) that contains the configuration for that wiki. Internally, moin adds a catch all ('wikiconfig', '.*') to the end of that list, so you do not need something like this in farmconfig.wikis.

farmconfig.py in the distribution archive has some sample entries for a wiki farm running multiple wikis, you need to adapt it to match your needs, if you want to run multiple wikis.

For simpler writing of these help pages, we will call such a <wikiname>.py configuration file simply wikiconfig.py, of course you have to use the filename you chose.

Of course you have already adapted the wikis setting in farmconfig.py (see above), so we only give some hints how you can save some work. Please also read the single wiki configuration hints, because it explains config inheritance.

We now use the class-based configuration to be able to configure the common settings of your wikis at a single place: in the base configuration class (see farmconfig.py for an example).

The configs of your individual wikis then only keep the settings that need to be different (like the logo, or the data directory or ACL settings). Everything else they get by inheriting from the base configuration class, see moinmaster.py for a sample.

# -*- coding: iso-8859-1 -*-
# farmconfig.py:
from MoinMoin.multiconfig import DefaultConfig
class FarmConfig(DefaultConfig):
    url_prefix = '/wiki'
    show_hosts = 1
    underlay_dir = '/where/ever/common/underlay'
    # ...

Explanation:

• first we import the default config, like we do when configuring a single wiki
• now we define a new farm config class - and inherit from the default config
• then we change everything that our farm wikis have in common, leaving out the settings that they need to be different

• this FarmConfig class will now be used by the config files of the wikis instead of moin's internal DefaultConfig class, see below:

# -*- coding: iso-8859-1 -*-
# wikiconfig.py:
from farmconfig import FarmConfig
class Config(FarmConfig):
    show_hosts = 0
    sitename = u'MoinMaster'
    interwikiname = 'MoinMaster'
    data_dir = '/org/de.wikiwikiweb.moinmaster/data/'
    # ...

Explanation:

• see single wiki configuration, the only difference is that we inherit from FarmConfig (that inherited from DefaultConfig) instead of directly using DefaultConfig

• now we override show_hosts to be 0 - we want it for most wikis in our farm, but not for this one
• we also override sitename, interwikiname and data_dir (the usual stuff)

3. Overview of configuration options

The following table contains default values and a short description for all configuration variables. Most of these can be left at their defaults, those you need to change with every installation are listed in the sample wikiconfig.py that comes with the distribution.

Starting with moin 1.3.1, some values MUST be Unicode. This is achieved like this: u'encoded string' (the u is the important thing and means to convert the encoded string to Unicode). Also, the encoding used for your config file must be given in the "coding" line at top of the file. For English (and some other western languages), use iso-8859-1, for others you may want to use utf-8.

Some values can only be set from MoinMoin/config.py (part of the MoinMoin code and thus GLOBALLY changing behaviour of all your wikis), but not from the individual wiki's config - you should only touch them if you know what you are doing:

4. Default front page

The default front page name, "FrontPage", is automatically translated into the user language. Thus, an English user will end up at FrontPage, while a French user will end up at PageD'Accueil.

If you have made your own front page which is suitable for all people regardless of their spoken languages, you should give it a different name (anything but "FrontPage" will do) and set the page_front_page setting to this name. For example:

page_front_page = 'MyFrontPage'

5. Changing character sets

Do not. By default, moin uses unicode (depending on your python, it will use either ucs-2 16bit or ucs-4 32bit chars) internally and utf-8 as external character encoding.

You should not have to change this, as any character can be encoded in utf-8. So we do not recommend changing the default. We also do not support non-utf-8 encodings, although it is technically possible:

# MoinMoin/config.py - this is GLOBAL for all wikis in your installation!
charset = "iso8859-1"
upperletters = "A-Z"
lowerletters = "0-9a-z"

With that setting, you need to set "allow_extended_names=1" and use the special markup for extended WikiNames ["extended name"] to get any names with characters outside the core latin alphabet.

6. File attachments

The AttachFile action enables a page to have multiple attached files. Since file uploads could be abused for DoS (Denial of Service) attacks, AttachFile is an action that may be enabled by the wiki administrator. To do this, add "allowed_actions = ['AttachFile']" to your configuration file.

If you wiki has (or is expected to have) many file attachments, there is an option which will eliminate the CGI overhead associated with each retrieval of an attachment file.

If you do not know how to do that, do not configure your moin like described below or you risk making your server remotely exploitable.

There are two storage/retrieval models for file attachments:

1. Attachments are stored "privately" and can only be retrieved via a CGI GET (via URLs like http://myorg.org/mywiki/<SomePage>?action=AttachFile&do=get&target=filename.ext).

2. Attachments are stored into a directory directly accessible by the web server, and can thus be served directly by the webserver, without any invocation of MoinMoin (leading to URLs like http://myorg.org/mywikiattach/<Somepage>/attachments/filename.ext).

If the efficiency of serving file attachments is a concern, the second option is preferable, but it also requires additional configuration steps and possibly more rights on the host machine. Because of this, the first option is the default; attachments are stored in the "...mywiki/data/pages/" directory, with paths like "...mywiki/data/pages/<pagename>/attachments/<filename>".

The MoinMoin attachments configuration option allows you to move the directory structure used to store attachments to another location. Unless you have a reason for doing so, there is no need to use a different location. Using a different location may be more work and more risk, as all the existing attachments must be copied to the new location. The following instructions are for Apache servers and assume you intend to leave the attachment files in their existing location and your original installation used the name "mywiki".

The first step is to tell Apache that it has another Alias directory from which it can serve files. Review the changes you made to the httpd.conf (or commonhttpd.conf) file during the MoinMoin installation and find the ScriptAlias statement similar to the following:

    ScriptAlias /mywiki           ".../mywiki/moin.cgi" 

Create an Alias statement similar to the ScriptAlias statement above, replacing the /mywiki URI with /mywikiattach/ and replacing moin.cgi with data/pages/.

    Alias       /mywikiattach/    ".../mywiki/data/pages/"

Be sure to note the differences in the trailing slashes between the two statements, they must be entered exactly as shown above. If you are making this change to a running system, you must restart Apache to have the change take effect.

The second step is to tell MoinMoin to let Apache do the work of fetching file attachments. To do this, you need to add an attachments option to .../mywiki/wikiconfig.py. The 'attachment' option is a dictionary of two values:

attachments = {
    'dir': '.../mywiki/data/pages',
    'url': '/mywikiattach',
}

MoinMoin must still do the work of uploading file attachments. The dir value above tells MoinMoin where to store attachments; note this is the same as the path in the new Apache Alias statement but without the trailing "/". The url value tells MoinMoin how to retrieve the attachments; this matches the URI in the Alias statement but again without the trailing "/".

Your attached files are now directly servable by Apache. However if you also have PHP (or ASP or any other server parsed language) installed then an attacker can upload a PHP script an then run it to exploit other local weaknesses.

For example, you can disable PHP for the appropriate directory (note that it's difficult to include instructions for disabling all server parsed languages).

<Directory .../mywiki/data/pages/>
    RemoveType .php .php3 .php4 .phtml
</Directory>

This only disables php stuff - you have to add everything else on your own!

After you have completed the configuration changes, test by uploading an attachment for WikiSandBox. Then modify the WikiSandBox page to display the uploaded image or download the file. If there were existing attachments before this change, verify the old attachments are still available. Finally, review the Apache access.log file to verify you have a log entry showing the expected file access:

• "...GET /mywikiattach/WikiSandBox/attachments/mypix.jpg HTTP/1.1...".