# style access, caching

**URL:** <https://discourse.citationstyles.org/t/style-access-caching/579>\
**Category:** CSL Development\
**Created:** [March 23, 2009, 1:11pm UTC](https://discourse.citationstyles.org/t/style-access-caching/579 "2009-03-23T13:11:25Z")\
**Posts on this page:** 9\
**Page:** 1

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**Author:** ![Bruce\_D\_Arcus1](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bruce\_D\_Arcus1](https://discourse.citationstyles.org/u/Bruce_D_Arcus1)\
**Post date:** [March 23, 2009, 1:11pm UTC](https://discourse.citationstyles.org/t/style-access-caching/579/1 "2009-03-23T13:11:25Z")

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So as Frank works on this tests and such, I’d like to raise an issue  
for discussion, and that I would hope make it into the unit tests and  
documentation.

How should a style be accessed?

Sub-issues:

1. files names vs. ids

Right now, implementations are typically just using some variant of  
accessing a file; in pseudo-code:

STYLE\_FILE = 'apa.csl’  
style = CSL.new(STYLE\_FILE)

But we have an Atom-based metadata system that this fails to exploit.  
So what I want to suggest, instead, is that the (or at least a)  
constructor is the style id; e.g.:

STYLE\_ID = '[http://zotero.org/styles/apa](http://zotero.org/styles/apa)’  
style = CSL.new(id = STYLE\_ID)

1. caching

Styles include update date-time stamps. The purpose here is enable  
smart caching and updating. Can we say that implementations should  
implement this? If yes, then should we suggests details on how (which  
might borrowing some Atom documentation and adapting it for our use)?

1. storage

Shouldn’t CSL styles be cached in a fixed (but perhaps configurable)  
local directory? E.g., at least in Unix/Linux/Mac OS:

.csl/  
styles/

I have styles as a subdirectory to leave room for other stuff (maybe  
config file to list CSL repos? some default behavior?).

So if all of these are implemented, it means that I can be assured  
that if I have two different applications using CSL on my system, that  
if I say to use the style “[http://zotero.org/styles/apa](http://zotero.org/styles/apa)” then I am  
assured both that a) they are using the same style, and b) that the  
style is up-to-date.

Thoughts?

Bruce

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**Author:** ![Bruce\_D\_Arcus1](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bruce\_D\_Arcus1](https://discourse.citationstyles.org/u/Bruce_D_Arcus1)\
**Post date:** [March 23, 2009, 2:30pm UTC](https://discourse.citationstyles.org/t/style-access-caching/579/2 "2009-03-23T14:30:11Z")

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Like imagine a config file that looked something like:

“repos” : [  
“z” : “[http://zotero.org/styles/](http://zotero.org/styles/)”  
]

… where maybe by convention you could invoke the style by doing:

```
   style = CSL.new('z:apa')

```

E.g. the 'z" prefix expands to the uri a la xml namespace binding. Not  
important in a GUI app, but can be convenient with examples like  
pandoc + citeproc.

Bruce

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**Author:** ![Frank\_Bennett](https://yyz1.discourse-cdn.com/flex029/user_avatar/discourse.citationstyles.org/frank_bennett/32/198_2.png) [@Frank\_Bennett](https://discourse.citationstyles.org/u/Frank_Bennett)\
**Post date:** [March 23, 2009, 3:15pm UTC](https://discourse.citationstyles.org/t/style-access-caching/579/3 "2009-03-23T15:15:40Z")

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> > I have styles as a subdirectory to leave room for other stuff (maybe  
> > config file to list CSL repos? some default behavior?).
> 
> Like imagine a config file that looked something like:
> 
> “repos” : [  
> “z” : “[Zotero Style Repository](http://zotero.org/styles/)”  
> ]
> 
> … where maybe by convention you could invoke the style by doing:
> 
> ```
> style = CSL.new('z:apa')
> 
> ```

I think this would be something for Andrea and Simon to speak to. As  
far as I know, the development environment I’m using for citeproc-js  
(rhino) is not able to access content over  
the wire. The program has an area for system localization, though,  
where features like this  
could be implemented.

Frank

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**Author:** ![Simon\_Kornblith](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@Simon\_Kornblith](https://discourse.citationstyles.org/u/Simon_Kornblith)\
**Post date:** [March 23, 2009, 3:27pm UTC](https://discourse.citationstyles.org/t/style-access-caching/579/4 "2009-03-23T15:27:12Z")

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> So as Frank works on this tests and such, I’d like to raise an issue  
> for discussion, and that I would hope make it into the unit tests and  
> documentation.
> 
> How should a style be accessed?
> 
> Sub-issues:
> 
> 1. files names vs. ids
> 
> Right now, implementations are typically just using some variant of  
> accessing a file; in pseudo-code:
> 
> STYLE\_FILE = ‘apa.csl’  
> style = CSL.new(STYLE\_FILE)
> 
> But we have an Atom-based metadata system that this fails to exploit.  
> So what I want to suggest, instead, is that the (or at least a)  
> constructor is the style id; e.g.:
> 
> STYLE\_ID = ‘[http://zotero.org/styles/apa](http://zotero.org/styles/apa)’  
> style = CSL.new(id = STYLE\_ID)
> 
> 1. caching
> 
> Styles include update date-time stamps. The purpose here is enable  
> smart caching and updating. Can we say that implementations should  
> implement this? If yes, then should we suggests details on how (which  
> might borrowing some Atom documentation and adapting it for our use)?

Re: the above two options, maybe it makes more sense to copy styles  
locally than to cache them? It makes sense to check for updates to a  
style, but I’m not sure it’s a good idea to change a style without any  
user interaction.

> 1. storage
> 
> Shouldn’t CSL styles be cached in a fixed (but perhaps configurable)  
> local directory? E.g., at least in Unix/Linux/Mac OS:
> 
> .csl/  
> styles/
> 
> I have styles as a subdirectory to leave room for other stuff (maybe  
> config file to list CSL repos? some default behavior?).

I would suggest:  
~/Library/Application Support/CSL/Styles (Mac OS X)  
%AppData%/CSL/Styles (Windows)  
~/.csl/styles (Unix/Linux)

Simon

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**Author:** ![Simon\_Kornblith](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@Simon\_Kornblith](https://discourse.citationstyles.org/u/Simon_Kornblith)\
**Post date:** [March 23, 2009, 3:31pm UTC](https://discourse.citationstyles.org/t/style-access-caching/579/5 "2009-03-23T15:31:52Z")

</div>

As I said in my previous email, we might want to reconsider whether we  
should really try to remotely load CSL files, as opposed to  
downloading them for local use. In any case, though, this isn’t a  
feasible constructor in browser-based JS, because the HTTP request has  
to be done asynchronously with a callback to avoid freezing the UI  
thread. We’d have to have something more like

CSL.new(‘z:apa’, function(style) {  
// do something with the style object here  
})

which is not really a very friendly construction.

Simon

---

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**Author:** ![Bruce\_D\_Arcus1](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bruce\_D\_Arcus1](https://discourse.citationstyles.org/u/Bruce_D_Arcus1)\
**Post date:** [March 23, 2009, 4:36pm UTC](https://discourse.citationstyles.org/t/style-access-caching/579/6 "2009-03-23T16:36:06Z")

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> Re: the above two options, maybe it makes more sense to copy styles locally  
> than to cache them?

Sure, that’s fine. Just wanted to get the conversation going.

> It makes sense to check for updates to a style, but I’m  
> not sure it’s a good idea to change a style without any user interaction.

OTOH, this might be a config option. For example, I’d probably want it  
to be set to update automatically, though grant that not everyone  
would.

> 1. storage
> 
> Shouldn’t CSL styles be cached in a fixed (but perhaps configurable)  
> local directory? E.g., at least in Unix/Linux/Mac OS:
> 
> .csl/  
> styles/
> 
> I have styles as a subdirectory to leave room for other stuff (maybe  
> config file to list CSL repos? some default behavior?).
> 
> I would suggest:  
> ~/Library/Application Support/CSL/Styles (Mac OS X)  
> %AppData%/CSL/Styles (Windows)  
> ~/.csl/styles (Unix/Linux)

Seems reasonable.

Bruce2009/3/23 Simon Kornblith \<@Simon\_Kornblith\>:

---

<div class="post-metadata">

**Author:** ![Bruce\_D\_Arcus1](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bruce\_D\_Arcus1](https://discourse.citationstyles.org/u/Bruce_D_Arcus1)\
**Post date:** [March 24, 2009, 4:55pm UTC](https://discourse.citationstyles.org/t/style-access-caching/579/7 "2009-03-24T16:55:30Z")

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Just an FYI that I solicited some feedback on this from the Zotero forums.

[http://forums.zotero.org/discussion/6348](http://forums.zotero.org/discussion/6348)

Some good points, and Dan has what look at first glance like some good  
ideas on details (which I’ll look at in more detail later).

Bruce

---

<div class="post-metadata">

**Author:** ![Bruce\_D\_Arcus1](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bruce\_D\_Arcus1](https://discourse.citationstyles.org/u/Bruce_D_Arcus1)\
**Post date:** [March 28, 2009, 5:05pm UTC](https://discourse.citationstyles.org/t/style-access-caching/579/8 "2009-03-28T17:05:48Z")

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So just a head’s up that I’ve been playing a bit with some code, and  
what I’m doing ATM is having a directory organized like this:

~/.csl  
/styles  
index.json  
apa.csl  
…

The index file then looks like this:

{  
“[http://zotero.org/styles/apa](http://zotero.org/styles/apa)” : {  
“link”: “[http://zotero.org/styles/apa.csl](http://zotero.org/styles/apa.csl)”,  
“file”: “apa.csl”,  
“updated”: “2008-10-29T21:01:24+00:00”  
},  
“[http://zotero.org/styles/aag](http://zotero.org/styles/aag)”: {  
“link”: “[http://zotero.org/styles/aag.csl](http://zotero.org/styles/aag.csl)”,  
“file”: “aag.csl”,  
“updated”: “2008-10-29T21:01:24+00:00”  
}  
}

This might be all too simple ATM, but it does make it easy to load the  
right styles, to know when they need updating, etc., and does so using  
a lightweight standard format. Right now, for example, I have  
functions like:

def update\_styles():  
""“  
Updates the users’ style repository.  
”""  
for styles in styles\_index[‘styles’]:  
style.update(style[‘id’])

The update method would then look at the existing updated value and  
compare it against the server header for the link value.

Bruce

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<div class="post-metadata">

**Author:** ![Bruce\_D\_Arcus1](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bruce\_D\_Arcus1](https://discourse.citationstyles.org/u/Bruce_D_Arcus1)\
**Post date:** [March 28, 2009, 5:13pm UTC](https://discourse.citationstyles.org/t/style-access-caching/579/9 "2009-03-28T17:13:49Z")

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…

> The update method would then look at the existing updated value and  
> compare it against the server header for the link value.

Or, come to think of it, etags might be better.

Bruce