Using JpegXMPFrame to remotely access XMP inside JPGs over HTTP

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Using JpegXMPFrame to remotely access XMP inside JPGs over HTTP

Fergal Monaghan

Hi guys,

 

            I’ve been using JpegComFrame to access the comment block inside JPGs remotely by asking for e.g. http://sw.deri.org:8001/Photos/20071009162628.jpg;application%2frdf%2bxml

Now I want to switch over to using XMP and JpegXMPFrame: but when I run JigAdmin there isn’t the same dual MIME type options like with JpegComFrame. The only documentation I can find online on using JpegXMPFrame are single sentences like “This class will read the XMP marker from a jpeg file and return it depending on the Accept: header” [1] or “Used to extract XMP from Jpeg images.” [2] From this I can only guess that it is not possible to simply append the desired MIME type to the end of the URL, but to create an Accept header in the HTTP request. I’ve tried the following Java in an attempt to do this programmatically, with no luck:

URL modelURL = new URL("http://sw.deri.org:8001/Photos/20080201141047.jpg");

HttpURLConnection huc = (HttpURLConnection)modelURL.openConnection();

huc.addRequestProperty("accept", "xmp");

           

            How exactly do I use the Accept: header to retrieve just the XMP metadata over HTTP? What MIME type do I need to specify? Is there any documentation anywhere that could be useful? Help!


Fergal Monaghan,

PhD Candidate,

Digital Enterprise Research Institute,

National University of Ireland, Galway,

IDA Business Park,

Lower Dangan,

Galway,

IRELAND.

 

[1] http://jigsaw.w3.org/Doc/Programmer/api/org/w3c/jigsaw/frames/JpegXMPFrame.html

[2] http://jigsaw.basemirror.de/Doc/Reference/frames.html

 

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RE: Using JpegXMPFrame to remotely access XMP inside JPGs over HTTP

Fergal Monaghan

Hi guys,

 

            After receiving no response from anyone else who may have encountered/solved this problem (please see below), I revisited it, had a look at Jigsaw’s source and found fixes to a few problems so that now I can HTTP Get and Put XMP into/out of JPEGs remotely. I’d like to share my finds/fixes with you guys so that they can be added to the next distribution (fixes made to Jigsaw 2.2.6): please find attached the fixed source files (4 of them) and a short readme of what changes I made and why. I hope this helps,


Fergal Monaghan

Digital Enterprise Research Institute,
Galway,

Ireland.

 

 


From: [hidden email] [mailto:[hidden email]] On Behalf Of Monaghan, Fergal
Sent: 01 February 2008 16:11
To: [hidden email]
Subject: Using JpegXMPFrame to remotely access XMP inside JPGs over HTTP

 

Hi guys,

 

            I’ve been using JpegComFrame to access the comment block inside JPGs remotely by asking for e.g. http://sw.deri.org:8001/Photos/20071009162628.jpg;application%2frdf%2bxml

Now I want to switch over to using XMP and JpegXMPFrame: but when I run JigAdmin there isn’t the same dual MIME type options like with JpegComFrame. The only documentation I can find online on using JpegXMPFrame are single sentences like “This class will read the XMP marker from a jpeg file and return it depending on the Accept: header” [1] or “Used to extract XMP from Jpeg images.” [2] From this I can only guess that it is not possible to simply append the desired MIME type to the end of the URL, but to create an Accept header in the HTTP request. I’ve tried the following Java in an attempt to do this programmatically, with no luck:

URL modelURL = new URL("http://sw.deri.org:8001/Photos/20080201141047.jpg");

HttpURLConnection huc = (HttpURLConnection)modelURL.openConnection();

huc.addRequestProperty("accept", "xmp");

           

            How exactly do I use the Accept: header to retrieve just the XMP metadata over HTTP? What MIME type do I need to specify? Is there any documentation anywhere that could be useful? Help!


Fergal Monaghan,

PhD Candidate,

Digital Enterprise Research Institute,

National University of Ireland, Galway,

IDA Business Park,

Lower Dangan,

Galway,

IRELAND.

 

[1] http://jigsaw.w3.org/Doc/Programmer/api/org/w3c/jigsaw/frames/JpegXMPFrame.html

[2] http://jigsaw.basemirror.de/Doc/Reference/frames.html

 


JigsawJpegXMPSource.rar (15K) Download Attachment