handle_errors.R

# Look for OAI-PMH exceptions
# https://www.openarchives.org/OAI/openarchivesprotocol.html#ErrorConditions
# xml = parsed xml
# Return TRUE if OK or stop
# handle_errors <- function(xml) {
# nodeset <- xml2::xml_find_all(xml, ".//*[local-name()='error']")
# if( length(nodeset) > 0 ) {
# msgs <- sapply(nodeset, function(n)
# paste0( xml2::xml_attr(n, "code"), ": ", xml2::xml_text(n) ) )
# stop( paste0("OAI-PMH exceptions: ", paste(msgs, collapse="\n")) )
# }
#
# }
#

handle_errors<-function(xml) {
# find error tags
req<-xml2::xml_text(xml2::xml_find_first(xml, ".//*[local-name()='request']" ))
nodeset<-xml2::xml_find_all(xml, ".//*[local-name()='error']")
# collect error information, if any
if( length(nodeset) ==0 ) {
return(TRUE)
 } else {
errors<- lapply(nodeset, function(n)
 c(code=xml2::xml_attr(n, "code"),
message=xml2::xml_text(n) ) )
cond<- condition(c("oai-pmh_error", "error"),
message= paste0("OAI-PMH errors: ",
 paste( sapply(errors, paste, collapse=": "), collapse=",\n")),
request=req,
error_codes= sapply(errors, "[", "code") )
 stop(cond)
 }
}