SOAP Request and Response Read from and to file using libcurl - C - c

Question

I am trying to send a SOAP request from a xml file and send to a SOAP service and then read the response while saving it into a file, using libcurl.
An example request in an xml file is as followed:
<?xml version="1.0" encoding="UTF-8"?>
<soapenv:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:olm="http://127.0.0.1:1090/services/olmDSMN">
<soapenv:Header/>
<soapenv:Body>
<olm:getAllCommercialProducts soapenv:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"/>
</soapenv:Body>
</soapenv:Envelope>
The libcurl code I'm trying to use to make the read and write is as follows:
#define URL "http://192.168.56.101:8088/olmDSMN"
size_t write_data(void *ptr, size_t size, size_t nmeb, void *stream)
{
return fwrite(ptr,size,nmeb,stream);
}
size_t read_data(void *ptr, size_t size, size_t nmeb, void *stream)
{
return fread(ptr,size,nmeb,stream);
}
int sendMessage (char * inFile, char * outFile) {
//writing to file initially
FILE * rfp = fopen(inFile, "r");
if(!rfp) {
perror("Read File Open:");
// exit(0);
}
FILE * wfp = fopen(outFile, "w+"); //File pointer to write the soap response
if(!wfp) {
perror("Write File Open:");
// exit(0);
}
CURL *curl;
CURLcode res;
curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, URL);
curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_data); //Reads xml file to be sent via POST operationt
curl_easy_setopt(curl, CURLOPT_READDATA, rfp);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data); //Gets data to be written to file
curl_easy_setopt(curl, CURLOPT_WRITEDATA, wfp); //Writes result to file
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
return 1;
}
}
At the moment the above does not work. When the function is invoked is just waits(as if waiting on a response that never comes). I'm just learning libcurl, so I'm sure I've done many things incorrectly. I've really been piecing together a couple different tutorials to get it do what I want it to do. Any assistance would be greatly appreciated.

Answer 1

Ok, so after a whole load of fiddling and piecing together code from different examples I've figured out how to perform the above task. See code below:
#include <stdio.h>
#include <string.h>
#include <curl/curl.h>
#define URL "http://192.168.56.101:8088/olmDSMN"
size_t write_data(void *ptr, size_t size, size_t nmeb, void *stream)
{
return fwrite(ptr,size,nmeb,stream);
}
size_t read_data(void *ptr, size_t size, size_t nmeb, void *stream)
{
return fread(ptr,size,nmeb,stream);
}
int sendMessage (char * inFile, char * outFile) {
//writing to file initially
FILE * rfp = fopen(inFile, "r");
if(!rfp) {
perror("Read File Open:");
// exit(0);
}
FILE * wfp = fopen(outFile, "w+"); //File pointer to write the soap response
if(!wfp) {
perror("Write File Open:");
// exit(0);
}
struct curl_slist *header = NULL;
header = curl_slist_append (header, "Content-Type:text/xml");
header = curl_slist_append (header, "SOAPAction: myur1");
header = curl_slist_append (header, "Transfer-Encoding: chunked");
header = curl_slist_append (header, "Expect:");
CURL *curl;
CURLcode res;
curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, URL);
curl_easy_setopt(curl, CURLOPT_POST, 1L);
curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_data); //Reads xml file to be sent via POST operationt
curl_easy_setopt(curl, CURLOPT_READDATA, rfp);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data); //Gets data to be written to file
curl_easy_setopt(curl, CURLOPT_WRITEDATA, wfp); //Writes result to file
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, header);
curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE_LARGE, (curl_off_t)-1);
// curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "POST");
curl_easy_setopt(curl, CURLOPT_VERBOSE,1L);
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
return 1;
}
}

Answer 2

Presuming that your SOAP server expects a HTTP POST, you need to:
Set the CURLOPT_POST option;
Set the Content-Type header Content-Type: application/soap+xml using CURLOPT_HTTPHEADER;
Set the size of your XML request using the CURLOPT_POSTFIELDSIZE option.