commentator 0.1

WSGI commenting middleware

To use

Make a factory wrapping your app in the commentator middleware. Currently, commentator only pickles comments. To the constructor of Commentator, pass a database (the path to the pickle) and a pattern. The pattern is in the form of

<URL pattern>#<xpath pattern> -> URL

The URL pattern is a python regular expression to match against the request's PATH_INFO.

The xpath pattern is where you want to place the comments on the page. See http://www.w3schools.com/XPath/ for more about xpath expressions.

The URL is a python string template that is substituted for groups in the URL regular expression and element attributes in the found nodes. The element attributes are referenced by name (${id}, ${class}, etc) and the groups are referenced by number (${1}, ...).

Example

A reference implementation is illustrated in the commentator.ini file. This uses the pattern:

commentator.pattern = (.*)#.//div[@id='comment_on_this'] -> ${1}

What this pattern says is

• comment on every PATH_INFO (.*)
• append the rendered content template to div[@id='comment_on_this']
• reference the PATH_INFO as the canonical URL ${1}

To comment on every HTML page at the end of the body, you would use

commentator.pattern = (.*)#.//body -> ${1}

A more complex example is in the .ini file, commented out, for use with bitsyblog :

commentator.pattern = /blog/.*#.//div[@class='blog-entry'] -> /blog/${id}

This pattern says:

• comment on all paths under blog
• put the comments at the end of each div[@class='blog-entry']
• get the URI from the div's id, not from the PATH_INFO

TODO

This is very alpha. I'd be happy to work more on this if anyone wants it. A few outstanding issues:

• fix weird lxml issue where you have to put .// for elements
• allow commenting on multiple resources (multiple patterns per instance)
• locking pickle files
• fix couch....not sure what's wrong
• allow use of CSS classes, not just xpath

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