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Re: [whatwg] Accessing local files with JavaScript portably and securely

From: Jan Tosovsky <jan.tosovsky.cz@gmail.com>
Date: Tue, 11 Apr 2017 00:38:21 +0200
Message-ID: <58ec095f.dd451c0a.51f62.0086@mx.google.com>
To: "'WHAT Working Group'" <whatwg@whatwg.org>
On 2017-04-10 David Kendal wrote:
> On 2017-04-09 Jan Tosovsky wrote:
> > On 2017-04-09 David Kendal wrote:
> >
> > > ... there are many possible uses for local static files accessing
> > > other local static files: the one I have in mind is shipping static
> > > files on CD-ROM or USB stick...
> >
> > In this case the file structure is fixed so it can be exported as
> > JSON file and then linked via the HTML header in every HTML file where 
> > it is needed. This structure is then directly available for the further
> > processing.
> >
> > However, I am not sure this covers your use case.
> 
> I'm not sure either, because I don't understand what you're proposing.
> What feature of the HTML header enables this functionality? (For an
> arbitrary number of files which may be wanted by an arbitrary number
> of other files, and which could be very large.)

Imagine e.g. WebHelp composed of collection of static files with Table of Contents (ToC) in the left pane. It is not very efficient to generate large ToC into every single HTML file. If you extract ToC into a dedicated HTML page, it cannot be imported by standard means directly into another HTML page (analogically to XML Inclusions [1]). You have to use either IFrame, or, better, provide ToC as JSON file. JSON is kind of javascript which can be linked via the <script> tag in the HTML header. It is hence loaded together with the page and you can manipulate it further with javascript. In case of ToC to render data as itemized list with proper CSS classes and even detect if the current item matches the actual page (if so use a different class).

So basically you need
(1) JSON
(2) link to that JSON in your HTML file
(3) JavaScript in your HTML file, which renders JSON data to the page

In my case both WebHelp pages and JSON is generated via XSLT from XML source.

If you have to list the file structure of CD-ROM, I suppose it is fixed so it doesn't need to be determined dynamically, but in advance. I can imagine simple Java 'walker'[2] which could traverse all the folder content and export all necessary data into JSON structure.

Jan


_____________
[1] https://www.w3.org/TR/xinclude/
[2] https://docs.oracle.com/javase/tutorial/essential/io/walk.html
Received on Monday, 10 April 2017 22:38:56 UTC

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