Is Comments field XHTML compliant?

itimpi · 08-24-2011, 04:22 AM

I am looking at an issue in the calibre2opds software that relates to our handling of the Calibre Comments field when it contains characters outside the cp1252 character set. What we are finding is these characters are ending up displaying incorrectly in our generated catalogs.

At the moment we have some code that uses 3rd party libraries to 'tidy' the Comments field and ensure it is XHTML compliant for inclusion into an OPDS catalog. This code dates from the days before Calibre properly supported HTML comments which was why it was originally used. We have tracked down our issue to the fact that the library we are using does not seem to be handling the comments field correctly if contains these non-cp1252 characters. Before we try and 'tidy' the comments field it is correctly stored in Java (which uses UTF-16 strings). If we by-pass the tidy code then the problem goes away and our generated catalogs display correctly.

The question therefore is whether it is now safe to assume that the Calibre comments field read from the database is already XHTML compliant? If we can then a lot of work can be avoided in calibre2opds to fix code that is no longer needed.

user_none · 08-24-2011, 06:51 AM

I don't know the answer but a simple test would be to put non-xhtml compliant data into a comment. Then when it is exported check the data against the XHTML scheme and see if it passes.

kovidgoyal · 08-24-2011, 12:18 PM

No, there is no such guarantee. But if I were you, I wouldn't worry about XHTML compliance. Just stick the html into a webpage, I seriously doubt any browser will have difficulty displaying it as long as you dont declare the page to be XHTML compliant.

Alternatively, duplicate the comments_to_html function from calibre, that is what calibre uses when inserting the contents of html fields into epub/content server pages.

itimpi · 08-24-2011, 12:46 PM

Quote:

Originally Posted by kovidgoyal

No, there is no such guarantee. But if I were you, I wouldn't worry about XHTML compliance. Just stick the html into a webpage, I seriously doubt any browser will have difficulty displaying it as long as you dont declare the page to be XHTML .

Note that we are talking bout an OPDS compatible client here - not a browser. I thought the OPDS standard mandated that the comments field had to be XHTML compliant in an OPDS catalog? However if you reckon that it does not seem to matter, I am happy to run with that as a working assumption.

kovidgoyal · 08-24-2011, 12:52 PM

It doesn't have to be XHTML compliant, just valid XML.

08-24-2011, 04:22 AM	#1
itimpi Wizard Posts: 4,552 Karma: 950151 Join Date: Nov 2008 Device: Sony PRS-950, iphone/ipad (Marvin/iBooks/QuickReader)	Is Comments field XHTML compliant? I am looking at an issue in the calibre2opds software that relates to our handling of the Calibre Comments field when it contains characters outside the cp1252 character set. What we are finding is these characters are ending up displaying incorrectly in our generated catalogs. At the moment we have some code that uses 3rd party libraries to 'tidy' the Comments field and ensure it is XHTML compliant for inclusion into an OPDS catalog. This code dates from the days before Calibre properly supported HTML comments which was why it was originally used. We have tracked down our issue to the fact that the library we are using does not seem to be handling the comments field correctly if contains these non-cp1252 characters. Before we try and 'tidy' the comments field it is correctly stored in Java (which uses UTF-16 strings). If we by-pass the tidy code then the problem goes away and our generated catalogs display correctly. The question therefore is whether it is now safe to assume that the Calibre comments field read from the database is already XHTML compliant? If we can then a lot of work can be avoided in calibre2opds to fix code that is no longer needed.

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08-24-2011, 06:51 AM	#2
user_none Sigil & calibre developer Posts: 2,488 Karma: 1063785 Join Date: Jan 2009 Location: Florida, USA Device: Nook STR	I don't know the answer but a simple test would be to put non-xhtml compliant data into a comment. Then when it is exported check the data against the XHTML scheme and see if it passes.

08-24-2011, 12:18 PM	#3
kovidgoyal creator of calibre Posts: 43,843 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	No, there is no such guarantee. But if I were you, I wouldn't worry about XHTML compliance. Just stick the html into a webpage, I seriously doubt any browser will have difficulty displaying it as long as you dont declare the page to be XHTML compliant. Alternatively, duplicate the comments_to_html function from calibre, that is what calibre uses when inserting the contents of html fields into epub/content server pages.

08-24-2011, 12:52 PM	#5
kovidgoyal creator of calibre Posts: 43,843 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	It doesn't have to be XHTML compliant, just valid XML.

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