R devel - Dec 2002 - problem with load('http://....') (PR#2344)

Full_Name: Frank Harrell
Version: 1.6.1
OS: RedHat 8.0 Linux
Submission from: (NULL) (128.143.108.90)


I get an error when trying to load a URL that contains a file that was saved
using save(object, compress=TRUE):
>
load('http://hesweb1.med.virginia.edu/biostat/s/data/sav/kprats.sav')
Error in gzfile(file, "rb") : unable to open connection
In addition: Warning message:
cannot open compressed file
`http://hesweb1.med.virginia.edu/biostat/s/data/sav/kprats.sav'

The above file will remain at that URL for your testing.

Thank you very much,

Frank Harrell

fharrell@virginia.edu writes:
> Full_Name: Frank Harrell
> Version: 1.6.1
> OS: RedHat 8.0 Linux
> Submission from: (NULL) (128.143.108.90)
> 
> 
> I get an error when trying to load a URL that contains a file that was
saved
> using save(object, compress=TRUE):
> 
> >
load('http://hesweb1.med.virginia.edu/biostat/s/data/sav/kprats.sav')
> Error in gzfile(file, "rb") : unable to open connection
> In addition: Warning message:
> cannot open compressed file
> `http://hesweb1.med.virginia.edu/biostat/s/data/sav/kprats.sav'
> 
> The above file will remain at that URL for your testing.
The root of the issue is that gzfile() doesn't know about URLs. Not
documented to either, but (on the face of things) it would seem easy
to add the feature.

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk)             FAX: (+45) 35327907

On Wed, 4 Dec 2002 ripley@stats.ox.ac.uk wrote:
> On 4 Dec 2002, Peter Dalgaard BSA wrote:
> 
> > fharrell@virginia.edu writes:
> >
> > > Full_Name: Frank Harrell
> > > Version: 1.6.1
> > > OS: RedHat 8.0 Linux
> > > Submission from: (NULL) (128.143.108.90)
> > >
> > >
> > > I get an error when trying to load a URL that contains a file
that was saved
> > > using save(object, compress=TRUE):
> > >
> > > >
load('http://hesweb1.med.virginia.edu/biostat/s/data/sav/kprats.sav')
> > > Error in gzfile(file, "rb") : unable to open connection
> > > In addition: Warning message:
> > > cannot open compressed file
> > >
`http://hesweb1.med.virginia.edu/biostat/s/data/sav/kprats.sav'
> > >
> > > The above file will remain at that URL for your testing.
> >
> > The root of the issue is that gzfile() doesn't know about URLs.
Not
> > documented to either, but (on the face of things) it would seem easy
> > to add the feature.
> 
> Right, this is not what the `file' argument of load() is documented as.
> That is neither a file name nor a connection.
> 
> I am worried about attempting to get a binary file over a url connection,
> but in principle what you should do is
> 
>
load(url('http://hesweb1.med.virginia.edu/biostat/s/data/sav/kprats.sav'))
> 
> That fails I think because the connection cannot handle binary files,
> but I will look further when I have time.
> 
Not sure if being binary creates problems as such, but what the
connection would provide if it is working properly is the compressed
data, and we wo not currently have the tools to decompress off a
connection, as far as I know.

luke

-- 
Luke Tierney
University of Iowa                  Phone:             319-335-3386
Department of Statistics and        Fax:               319-335-3017
   Actuarial Science
241 Schaeffer Hall                  email:      luke@stat.uiowa.edu
Iowa City, IA 52242                 WWW:  http://www.stat.uiowa.edu