Re: [Plastic-devs] file-scheme URLs again

[Thomas B. <bo...@ne...>]

Mark,

That's very annoying indeed.
I think that PLASTIC-aware Java applications should still be able to
deal with file URLs of the form "file://localhost/path" as those URLs
are perfectly valid. Thus, the workaround #1 seems indispensable IMHO.

Thomas


Mark Taylor wrote:
> 
> On Wed, 10 May 2006, Johan Lindroos wrote:
> 
> > Hello Mark,
> >
> > I did some more tests, and get weird symptoms :-/
> >
> > The working version i have is when I create an URL url object from the
> > incoming string.
> > from that i create a File object new File(url.getPath()); this works nicely
> >
> > But also the following should work.
> >
> > URL url = new URL(incoming)
> > URI uri = url.toURI();
> >
> > File file = new File(uri);
> > //program locks here without any exceptions if the url contained the
> > localhost part, if you remove the localhost before creating the url obj
> > it works nicely also.
> 
> Yes, I get the following error there:
> 
>    java.lang.IllegalArgumentException: URI has an authority component
> 
> If I feed the File(URI) constructor a URI which does not contain the
> authority component (e.g. "file:///path" rather than
> "file://localhost/path") this problem goes away.  However Java won't
> let you create URLs in this form: the result of
> new URL("file:///path").toExternalForm() is "file:/path".
> 
> > It seems as it's actually java that does not follow the URL standards I
> > think.
> 
> Unfortunately that's true - see
> 
>    http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6351751
> 
> What a mess.  It seems impossible to pass around URL/URI objects
> in any form which both conforms to RFC1738 and which Java won't
> choke on under some circumstances.
> 
> The only workarounds I can think of for this are as follows:
> 
>    1.  Avoid use of the File(URI) constructor.  There may be other places
>        where similar problems crop up - we'll have to watch for these.
> 
>    2.  Give in and use non-conformant file-scheme URLs in the form
>        that Java produces them (file:path); this will effectively
>        require non-java PLASTIC applications to be prepared to
>        deal with illegal URLs.
> 
>    3.  Wait until Sun fixes it.  I suspect that might take a while
>        because of backward compatiblity problems, and in any case
>        this doesn't help applications running on older JVMs.
> 
> 1 is probably the Right Thing To Do.  However, since new java
> applications are going to keep tripping over this and in practice
> it's a lot more fiddly to fix than you might think, I suspect the
> best thing to do in practice is 2.  This requires the java
> PLASTICers humbly to ask the non-java PLASTICers to accommodate
> the deficiencies of the J2SE.  Does anyone from either the java or
> non-java side have an opinion on this?
> 
> Mark
> 
> >
> > >On Wed, 10 May 2006, Johan Lindroos wrote:
> > >
> > >
> > >
> > >>Hello Mark,
> > >>
> > >>I got the same problem in windows, but the problem is not due to the
> > >>"8char" directories but the localhost part, that does not work well,
> > >>when removing the localhost from the url before accessing the temporary
> > >>file it works well.
> > >>
> > >>Best Regards,
> > >>  Johan
> > >>
> > >>Johan Lindroos, Software Engineer, SAMPO ESO - Data Analysis Project
> > >>P.O.Box 405, 02101 ESPOO, Finland Tel.+358-9-4572121, Mob.+358-50-3819725, Fax. +358-9-4572302
> > >>CSC - Scientific Computing Ltd. http://www.csc.fi Email: Joh...@cs...
> > >>
> > >>
> > >
> > >oh lordy... the URLs generated by TOPCAT didn't used to contain the
> > >localhost part in 'file:'-type URLs, but I've done work to insert it
> > >following discussions on this list last month about correctly
> > >formed URLs, in accordance with RFC 1738.  Now it seems that they
> > >are not being parsed correctly.
> > >
> > >Can you tell me exactly what is failing when trying to handle such URLs?
> > >
> > >thanks
> > >
> > >Mark
> 
> --
> Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
> m.b...@br... +44-117-928-8776 http://www.star.bris.ac.uk/~mbt/
> 
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