Help from the rOpenSci community

[Nico Carver]

If you use rOpenSci to manipulate Dryad metadata, I could use your help. 

I have tried running through the tutorial (http://ropensci.org/tutorials/dryad-tutorial/) and I am getting error messages I don't fully understand.

I was able to retrieve the idlist to see how many data packages and files there are,

> idlist <- ListIdentifiers('r')

> length(idlist[[2]])

[1] 1406

> length(idlist[[1]])

[1] 3379

but when I tried the examples in workflow 1 I get error messages like this:

> url <- download_url("33867")

XPath error : Undefined namespace prefix

XPath error : Invalid expression

Error in xpathApply.XMLInternalDocument(page, "//mets:FLocat", function(x) { : 

  error evaluating xpath expression //mets:FLocat

or this:

> metadata <- download_dryadmetadata("10255/dryad.33867", T)

Error in OAI_PMH_issue_request(baseurl, request) : 

  Received condition 'idDoesNotExist' with diagnostic:

"10255/dryad.33867" is unknown or illegal in this repository

It seems that I am using improper syntax in my request. Any ideas?

Thanks,

--Nico

[Scott Chamberlain]

Hi Nico, 

Apologies for the errors.  We unfortunately have not updated that tutorial in quite a while.  

The first error you got can be fixed by using: 

url <- download_url("10255/dryad.33867") # add the "10255/dryad." in front of the number

The second error by:

metadata <- download_dryadmetadata("oai:datadryad.org:10255/dryad.33867", T) # add the "oai:datadryad.org:" in front of the dryad identitifer

If you install dryad using 

install.packages("devtools")
require(devtools)
install_github("dryad", "ropensci")
require(dryad)

you can look at the documentation which should have all up to date working examples now.  

We will fix the tutorial on our website ASAP.  

Thanks for the bug report! 

Scott Chamberlain 

-rOpenSci team