Thanks for the the responses, Martin and Hervé. I apologize for the sparse details. I didn't provide the actual URL because I didn't have the express permission of the API's authors to share it publicly and it's still in private beta. I have since communicated with the authors and was told it would be okay to share details with the BioConductor community. The API is for a suite of bioinformatic web applications available at http://toppgene.cchmc.org. Details about the API can be found at http://toppgene.cchmc.org/wiki. Anyway, Martin's suggestion was definitely a step in the right direction. I was able to successfully make a call to the API with the code he provided. However, this returned the following error message: The specified HTTP method is not allowed for the requested resource (HTTP method GET is not supported by this URL). How I could I make a similar call using the PUT or POST method instead of GET? As per Hervé Pagès suggestion I perused the source code for biomaRt and found it uses the postForm function. Perhaps that is what should to be used with the ToppGene API. On Sun, Sep 13, 2009 at 3:37 PM, Martin Morgan <mtmorgan@fhcrc.org> wrote: > Hi Aaron -- > > Aaron Wolen wrote: > > I'd like to access an API from within R but I'm not sure how to do so. > The > > API uses HTTP and supports both POST and PUT methods. I'm able to access > it > > successfully from the terminal using the following curl command: > > curl --data @genes.xml http://api-url > > > > > Where genes.xml is a local file containing the genes I want to submit and > > http://api-url is the API's address. However, I'm not sure how to > replicate > > this command in R. The request payload and response payload are both XML > > streams, so I'm fairly certain this will require a combination of the > RCurl > > and XML packages, but I've had no luck getting RCurl to work. I'd really > > appreciate some help with this. > > To get more help you'll probably have to provide more information about > what specifically is at the other end of the curl request, especially a > reproducible (as in, a real url and appropriate data argument, and an > indication of what you'd like back, e.g., as from the command line) > example. > > I think you want to end up using > > getURL("http://api-url", ...) > > where ... are arguments that capture the command line --data @genes.xml. > The place to look for ... is in the 'man' page for curl_easy_setopt, > where an option like CURLOPT_READFUNCTION becomes a named argument > 'readfunction'. I'd guess perhaps > > reader <- function(file) { > function() paste(readLines(file), collapse="\n") > } > > res <- getURL("http://api-url", readfunction=reader("genes.xml")) > > If the return value is XML or HTML, you might then > > xml <- xmlTreeParse(res, useInternal=TRUE) > > and the query xml with the xpath language, described here > http://www.w3.org/TR/xpath, especially section 2.5, abbreviated syntax. > > Hope that provides some help; if you provide something to explore > against, you might get some more explicit help. > > Martin > > > Thanks, > > Aaron > > > > [[alternative HTML version deleted]] > > > > _______________________________________________ > > Bioconductor mailing list > > Bioconductor@stat.math.ethz.ch > > https://stat.ethz.ch/mailman/listinfo/bioconductor > > Search the archives: > http://news.gmane.org/gmane.science.biology.informatics.conductor > > [[alternative HTML version deleted]]