RE: [Exist-open] storing binary files in eXist

[<km...@we...>]

I had the same problem. The resource reader has problems with binaries
stored in eXist or with xmldb:exist protocol. I have solved this problem by
implementing a BinaryResourceReader for binaries stored in eXist. There is
still a problem with the configuration of the HTTP Headers but otherwise it
works. I can give it to you if you are interested. I think it is good enough
for testing your CD-ROM use case....

Kai

> -----Original Message-----
> From: exi...@li...
> [mailto:exi...@li...]On Behalf Of Jakob Fix
> Sent: Wednesday, March 29, 2006 4:19 PM
> To: exi...@li...
> Subject: Re: [Exist-open] storing binary files in eXist
>
>
> Wolfgang, Adam,
>
> thanks for your replies.  Well, I've indexed all binary resources for
> testing purposes, and that went easy-peasy (I had to add the mime
> types for png and pdf files to the mime-types.xml file though).
>
> However, now that they are in the database I can't get them out ...
> I'm using Cocoon sitemaps.  I tried to change my sitemap accordingly,
> but no success ...
>
> In my mind, there are potentially two possibilities:
>
> 1) map:generate + map:serialize -- problem here is I don't know what
> serializer to use (the ones documented on the cocoon site are rather
> to convert for example from svg to png/jpg/younameit.)  "xml" is
> refused with an Internal Server Error, "pdf" is unknown, etc.
>   Example:
>   <map:generate src="xmldb:exist:///db/{1}/pdf/{2}.pdf"/>
>   <map:serialize type="???"/>
>
> 2) map:read  -- problem here is it seems the @src seems to pretend
> that it doesn't know about the xmldb:exist protocol.
>   Example:
>   <map:read mime-type="application/pdf"
> src="xmldb:exist:///db/{1}/pdf/{2}.pdf"/>
>
>
> I think I'm almost there, so if someone could give me that last push
> (over the cliff :-)) ...
> --
> cheers,
> Jakob.
>
>
> On 3/29/06, Adam Retter <ada...@de...> wrote:
> >
> >
> > On Tue, 2006-03-28 at 22:10 +0200, Jakob Fix wrote:
> > > Hello,
> > >
> > > I'm trying to improve retrieval speeds for an application running from
> > > CD-ROM.  I have several thousand XML resources in less than ten
> > > collections, and am happy with the speed they are retrieved.  I guess
> > > because they are all in  .dbx files, and those are loaded into memory
> > > at the beginning of a user session, speeds are comparable to retrieval
> > > from the hard disk-based file system (even if they must be swapped to
> > > the hard disk).
> > >
> > > Now, I have about the same number of binary resources (PNGs for
> > > equations, JPEGs for figures, and PDF files) which currently reside on
> > > the CD-ROM's file system.  These files are only requested on demand,
> > > ie. when the user requests a page on which they appear. However, for
> > > some figure or equation-heavy pages, constant access to the CD-ROM
> > > makes the "user experience" less desirable.
> > >
> > > I am wondering, and here I would be grateful for your advice, whether
> > > it would be useful to add these resources to the database.  Would they
> > > use much more space in the database than in the file system (due to
> > > some indexation)?  What would the retrieval speeds be (probably, a big
> > > database file would have to be swapped out from memory to the file
> > > system).  How would access and search requests to the actual contents
> > > (the XML resources) be affected?
> >
> > You may store any resource in an eXist database, binary or otherwise.
> > They may take up slightly more space in the .dbx than if they were on
> > the filesystem, but I do not believe this is very much. Binary resources
> > are not indexed.
> >
> > I would recommend doing a small test and seeing what your results are
> > like, we store our entire web-app in the eXist db, but we have far fewer
> > binary resources than you are talking about.
> >
> > It is of course faster to retreive the binary resource from the
> > filesystem on fast storage than the eXist db as there is less processing
> > overhead, however a CDROM is fairly slow so im not sure how this would
> > compare?!?
> >
> > > Another important point: the application is to be used either directly
> > > from the CD-ROM, or after being copied to the hard disk.  This is why
> > > I do not provide a one-file-contains-all installer, but have a very
> > > lean installer that simply copies the complete application directory
> > > layout from the CD-ROM.
> > >
> > > At the moment, it takes about five to ten minutes to install the
> > > application, due to these many thousands of small files that need to
> > > be copied to the hard disk.  One way to remedy this problem would be
> > > to stuff all these files in the eXist database, but at what price?
> >
> > Try it.
> >
> > > Thanks for your help.
> > >
> > > --
> > > cheers,
> > > Jakob.
> > >
> > >
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> > --
> > Adam Retter
> > Devon Portal Developer
> >
> > Devon Portal Project
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> >
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> >
> >
>
>
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