Hi Ryan postForm() is using a different style (or specifically Content-Type) of submitting the form than the curl -d command. Switching the style = 'POST' uses the same type, but at a quick guess, the parameter name 'a' is causing confusion and the result is the empty JSON array - "[]".
A quick workaround is to use curlPerform() directly rather than postForm() r = dynCurlReader() curlPerform(postfields = 'Archbishop Huxley', url = 'http://www.datasciencetoolkit.org/text2people', verbose = TRUE, post = 1L, writefunction = r$update) r$value() This yields [1] "[{\"gender\":\"u\",\"first_name\":\"\",\"title\":\"archbishop\",\"surnames\":\"Huxley\",\"start_index\":0,\"end_index\":17,\"matched_string\":\"Archbishop Huxley\"}]" and you can use fromJSON() to transform it into data in R. D. On 4/29/11 12:14 PM, Elmore, Ryan wrote: > Hi everybody, > > I think that I am missing something fundamental in how strings are passed > from a postForm() call in R to the curl or libcurl functions underneath. For > example, I can do the following using curl from the command line: > > $ curl -d "Archbishop Huxley" "http://www.datasciencetoolkit.org/text2people"; > [{"gender":"u","first_name":"","title":"archbishop","surnames":"Huxley","start_index":0,"end_index":17,"matched_string":"Archbishop > Huxley"}] > > Trying the same thing, or what I *think* is the same thing (obvious not) in R > (Mac OS 10.6.7, R 2.13.0) produces: > >> library(RCurl) > Loading required package: bitops >> api <- "http://www.datasciencetoolkit.org/text2people"; >> postForm(api, a="Archbishop Huxley") > [1] > "[{\"gender\":\"u\",\"first_name\":\"\",\"title\":\"archbishop\",\"surnames\":\"Huxley\",\"start_index\":44,\"end_index\":61,\"matched_string\":\"Archbishop > > Huxley\"},{\"gender\":\"u\",\"first_name\":\"\",\"title\":\"archbishop\",\"surnames\":\"Huxley\",\"start_index\":88,\"end_index\":105,\"matched_string\":\"Archbishop > Huxley\"}]" > attr(,"Content-Type") > charset > "text/html" "utf-8" > > I can match the result given on the DSTK API's website by using system(), but > doesn't seem like the R-like way of doing something. > >> system("curl -d 'Archbishop Huxley' >> 'http://www.datasciencetoolkit.org/text2people'") > 158 141 141 141 > 0[{"gender":"u","first_name":"","title":"archbishop","surnames":"Huxley","start_index":0,"end_index":17,"matched_string":"Archbishop > Huxley"}] 17 599 72 --:--:-- --:--:-- --:--:-- 670 > > If you want to see some additional information related to this question, I > posted on StackOverflow a few days ago: > http://stackoverflow.com/questions/5797688/post-request-using-rcurl > > I am working on this R wrapper for the data science toolkit as a way of > illustrating how to make an R package for the Denver RUG and ran into this > problem. Any help to this problem will be greatly appreciated by the Denver > RUG! > > Cheers, > Ryan > > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
