pvsRequest9.1 <-
function (request,inputs) {
pvs.key <- getPVS_key() # check "pvs.key" option, then "pvs.key"
pvs.url <- paste("http://api.votesmart.org/",request,"key=", pvs.key, inputs, sep="") #generate url for request
httpresp <- GET(url=pvs.url)
xmltext <- content(x=httpresp, as="text")
errors <- getXMLErrors(xmltext) # check if xml can be parsed properly
if (length(errors) != 0) {
if (names(errors[[1]]$code) == "XML_ERR_CDATA_NOT_FINISHED") { # if not, try to fix
xmltext <- gsub(pattern="\003", replacement="", x=xmltext, fixed=TRUE)
}
}
output.base <- xmlRoot(xmlTreeParse(xmltext, useInternalNodes=TRUE))
if (names(output.base)[1]=="errorMessage") {
# if the requested data is not available, return an empty (NA) data frame and give a warning
warning(gsub(pattern="&", replacement=" ", x=paste("No data available for: ", inputs,". The corresponding rows in the data frame are filled with NAs.", sep=""), fixed=TRUE), call.=FALSE)
output.df <- data.frame(matrix(nrow=1,ncol=0), stringsAsFactors = FALSE)
output.df
} else {
output <- output.base
nodenames <- names(output) # get names of nodes
# remove unnecessary child-nodes
if (nodenames[1]=="generalInfo") {
output <- removeChildren(output,kids="generalInfo")
} else {
if (nodenames[1]=="generalinfo") {
output <- removeChildren(output,kids="generalinfo")
}
}
nodenames <- names(output) # get names of nodes
# process each relevant subnode of output (e.g., without generalinfo) individually
# specifically check if subnode has again subnodes with several entries such as stage in the Election.getElection above.Then process each individually
subnodes.list <- lapply(1:length(nodenames), FUN= function(x) {
subn <- output[[x]]
freq.names <- summary(as.factor(names(subn))) # check frequency
n.subnames <- sapply(names(freq.names), function(y) { length(names(subn[[y]]))}) # check number of subnodes in each element
if (sum(n.subnames)==length(n.subnames)) {
subnode.df <- data.frame(t(xmlSApply(subn, xmlValue)), stringsAsFactors = FALSE)
} else {
# first, extract xml values of subnodes of subnodes (would otherwise generate problematic columns)
severalsubn <- which(n.subnames>1)
sevsubs <- lapply (1:length(severalsubn), FUN=function(i) {
.sevsub <- which(names(subn)==names(severalsubn)[i]) # which subnodes (of subn) have several entries?
sevsub.list <- lapply(1:length(.sevsub), function(j){
df <- data.frame(t(xmlSApply(subn[[.sevsub[[j]] ]], xmlValue)), stringsAsFactors = FALSE)
df.names <- sapply(1:length(names(df)), FUN=function(z) {paste(names(.sevsub[j]),j,".",names(df)[z], sep="")})
names(df) <- df.names
df
}
)
sevsub.df <- do.call("cbind", sevsub.list)
}
)
sevsubs.extracted <- do.call("cbind", sevsubs)
# second, extract all xml values as usual (generates some problematic columns due to subnodes in subnodes)
# therefore only keep the normal ones:
df.ok <- data.frame(t(xmlSApply(subn, xmlValue)), stringsAsFactors = FALSE)
ok.names <- names(subn)[(names(subn)!=names(severalsubn)[1])]
df.ok <- df.ok[,ok.names]
# third, cbind the two data frames
subnode.df <- cbind(df.ok,sevsubs.extracted)
}
subnode.df
})
output.df <- bind_rows(subnodes.list)
return(output.df)
}
}
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