Calculating meta-data properties

[0xgeert]

I want to be able to calculate certain meta-data properties based on the values of other meta-data properties and/or values set in docpad.coffee / the environment.

I know the docpad.coffee part is possible. (I've read about it on stackoverflow today but can't seem to find it now) . However I'm particularly interested in calculating meta-data properties based on other meta-data properties.

E.g: when an explicit 'url' property is not defined I want to set it based on the sluggified 'title' property if that exists. I tried to quickly hack this using the renderBefore event, which I thought was appropriate but to no avail. (I'm more a javacsript than coffeescript guey so forgive the syntax clashes.. )

   renderBefore: (opts,next) -> 
        col = opts.collection
        col.models.forEach (m) -> 
            attribs = m.meta.attributes
            if(!attribs.url && attribs.title && attribs.layout.trim()=="post")
                attribs.url = "/posts/" + attribs.title.replace(/\ /g,'-')
                console.log attribs.url
        next()

Is this (or something close this this since it's obvisouly not working :), the correct way of doing this, or is there other more robust (declarative?) way to define calculated meta data properties?

BTW: hope you don't mind me flooding the issuelist. Rest assured it's a good thing. I'm pretty excited about Docpad :)

[greduan]

You mean something similar to this? https://github.com/Greduan/eduantech.docpad/blob/master/docpad.coffee#L29-L34

[0xgeert]

ha cool. yes indeed that's half of the equation. The other half would be to call the fictional getPreparedUrl somewhere and assign it to the meta-data property automatically if that isn't explicitly set already.

[greduan]

Well I think that other part would be found here: https://github.com/Greduan/eduantech.docpad/blob/master/docpad.coffee#L42-L46

Now if I understood what you need correctly, you would just need to put these together and get what you need no?

[0xgeert]

Damn I missed that :) Yup it seems trivial now thanks. Giving this a try now.

[0xgeert]

Great working. Thanks @Greduan !

  posts: (database) ->
        database.findAllLive({relativeOutDirPath: 'posts'}, [date:-1]).on 'add', (model) ->
            t = model.get('title')
            if(t)
                url = "/posts/"  + t.replace(/\ /g,'-')
                model.addUrl(url).setMetaDefaults({url:url})
            model.setMetaDefaults({layout:'post'})

[0xgeert]

To also cover the case of changing titles:

     # NOTE: events from http://documentcloud.github.io/backbone/#Collection
    posts: (database) ->
        database.findAllLive({relativeOutDirPath: 'posts'}, [date:-1]).on 'add change:title', (model) ->
            t = model.get('title')
            if(t)
                url = "/posts/"  + t.replace(/\ /g,'-')
                model.addUrl(url).setMetaDefaults({url:url})
            model.setMetaDefaults({layout:'post'})

[greduan]

Glad I was able to help. :)

Also thanks for that code, gives me an idea for something in my website. :)

[0xgeert]

@Greduan you may be interested in the updated version :)

        .on 'add change:title', (model) ->
            t = model.get('title')
            if(t)
                url = "/posts/"  + t.replace(/\ /g,'-')

                explicit_url = model.getMeta().get("url")
                if explicit_url
                    model.addUrl(url)
                else
                    model.setUrl(url).setMetaDefaults(url:url)

[greduan]

Awesome! Thanks!

Whenever I get to using it or something similar I'll be sure to tell you. :)