User:Datagrok

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User:Datagrok is the user page for Michael F. Lamb. My personal website is datagrok.org.

Contents 1 A little CGI wiki powered mostly by Apache .htaccess directives 1.1 Introduction 1.2 Core idea 1.3 But what about... 1.4 Details 2 Shorten the URL to your Subversion repository over ssh 2.1 Steps

A little CGI wiki powered mostly by Apache .htaccess directives

Introduction

Yet another wiki/cms thingy. It's small, fast, and simple. If you're a programmer, you can hack on it in your favorite CGI-capable language to add whatever features you like while still keeping the core "let apache do the work" design.

I built this to achieve this combination of features, which I could not find elsewhere:

• Optimized for speed under many reads, few writes.
  • All wiki pages are saved as static files and served by apache.
  • The only time a script is run is when a page is edited.

Thus, the only time a database (if any!) is queried (if at all!) is when a page is edited.

• Nice, clean URLs with multi-level heiarchy.
• Wiki pages may exist along side any other content, including HTML authored by other tools, or CGI scripts.
• No dependence on a database.
• No dependence on mod_rewrite.
• Apache does most of the work.
  • Apache serves all the flat files.
  • Apache provides (somewhat weak) authentication via mod_auth or mod_auth_db.
  • Options +MultiViews in .htaccess gives nice clean URLs.

Core idea

• Configure the 404 error page for the wiki-ized folder to point instead to a "create new page" script.

Thus, links into the wiki will result in a 404 which has a "create this page now" form at the bottom, or a redirect to an editor script.

That's enough for wiki-like functionality. Other features are orthogonal to this design. For my purposes, I'll also add:

• Multiple content types for modular, specialized editors. (Wiki pages, images, etc.)
• History tracked with standard version control tools.
  • I like Subversion because I already use it a lot on Dreamhost.
  • I might use Mercurial because I think I can "flatten" parts of the history, to completely eliminate any overhead caused by spam.
  • I hope to make this modular, so the user may use the VC they like.
• Smart markup using my own twist on Python's reStructuredText/Markdown

But what about...

• Common look-and-feel: Editor script wraps content in template or shtml includes.
  • Wrapping in a template would require re-rendering the entire site in the case of template change.
  • SSI incurs a small CPU/disk performance hit.
• Dynamic site map: Sitemap data written in JSON to base directory, HTML generated by javascript.
  • Care must be taken to make the site still navigable for Google and non-javascript browsers.

Details

/wiki/.htaccess contains:

Options +MultiViews
ErrorDocument 404 /wiki/edit/

/wiki/edit/.htaccess contains:

DirectoryIndex editor.py
# This is for password-protecting it:
AuthUserFile /full/path/to/htpasswd
AuthName "web editor"
AuthType Basic
<Limit POST>
require valid-user
</Limit>

/wiki/edit/editor.py performs a few tricks with CGI variables to figure out which file to edit:

import os
class Editor(object):
    def __init__(self):
        e = os.environ.get
        self.user = e('REMOTE_USER')
        self.host = e('HTTP_HOST')
        self.root = e('DOCUMENT_ROOT')
        edit_dir, dummy = os.path.split(e('SCRIPT_NAME'))
        parent, dummy = os.path.split(edit_dir[1:])
        path = None
        for prefix in [e('SCRIPT_NAME')+'/', e('REDIRECT_URL'), '/'+parent+'/']:
            if e('SCRIPT_URL').startswith(prefix):
                path = e('SCRIPT_URL')[len(prefix):]
                break
        path, file = os.path.split(path)
        if not file:
            file = "contents"
        self.parent = parent
        self.path = path
        self.file = file
e = Editor()
print 'Content-type:text/plain'
print
print repr((e.root, e.parent, e.path, e.file))

I'm still building this for my purposes, but that should be a good start...

Shorten the URL to your Subversion repository over ssh

Once you've set up your subversion repository on Dreamhost, your repository URL looks like this:

http://svn.hostname.com/project

If however you prefer the more secure svn-over-ssh access, by default you have to use a much longer URL:

svn+ssh://username@hostname.com/home/username/svn/project

But with a few additional configuration files, you can shorten that to:

svn+ssh://hn/project

Steps

1. Create a script that wraps svnserve with the default path to the repositories. Put in ~/bin/svnserve:

 #!/bin/sh
 /usr/bin/svnserve -r ~/svn/ "$@"

2. Make ~/bin/svnserve executable: chmod +x ~/bin/svnserve

3. Make sure that your ~/bin/svnserve is found in the PATH before the default/usr/bin/svnserve. Put into ~/.bashrc:

 export PATH=~/bin:$PATH

At this point, your repository URL for svn-over-ssh is

svn+ssh://username@hostname.com/project

You can further shorten this URL by configuring ssh to recognize a nickname for your host, and your preferred username there. On your (Unix) client machine, edit ~/.ssh/config:

 Host hn
   HostName hostname.com
   User username