First of all, I would like to know if there is any difference (execution-time) in C between:
- GET request made by using cURL
- GET request make by using sockets (BSD sockets)
Second, I've done a C program which parses a XML file (without using any xml-specific library) and makes a GET request with the parsed info as it follows:
http://www.example.com/k=content1|content2|content3
http://www.example.com/k=content4|content5|content6
and so on...
My XML file looks like this:
<tag1>
<tag2>
<Server>
<Host>content1</Host>
<User>content2</User>
<Pass encoding="base64">content3</Pass>
</Server>
<Server>
<Host>content4</Host>
<User>content5</User>
<Pass encoding="base64">content6</Pass>
</Server>
<Server>
<Host>content7</Host>
<User>content8</User>
<Pass encoding="base64">content9</Pass>
</Server>
</tag2>
</tag1>
My code uses just one function as this is how I want it done (without any parameter). Could you please answer my first question and provide some improvements / advices regarding my code ? ( what would you do / use / delete ). I would like to get a response regarding the GET requests then anything else if possible.
The code:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <curl/curl.h>
#define keyurl "http://www.link.com"
int getKeyVal(char *key);
// return data from the server
struct return_string {
char *ptr;
size_t len;
};
// utility functions
size_t accumulate(void *ptr, size_t size, size_t nmemb, struct return_string *s);
void init_string(struct return_string *s);
/* get the <key> */
int getKeyVal(char *key)
{
CURL *curl;
CURLcode res;
char url[128];
sprintf(url, "%s/k=%s", keyurl, key);
curl = curl_easy_init();
if (curl) {
struct return_string s;
init_string(&s);
curl_easy_setopt(curl, CURLOPT_URL, keyurl);
curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
curl_easy_setopt(curl, CURLOPT_REDIR_PROTOCOLS, CURLPROTO_HTTPS);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, accumulate);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, &s);
res = curl_easy_perform(curl);
printf("result: %s\n", s.ptr);
free(s.ptr);
curl_easy_cleanup(curl);
}
else {
res = -99;
}
return(res);
}
/* Initialize the string handler so that it is thread safe */
void init_string(struct return_string *s)
{
s->len = 0;
s->ptr = malloc(s->len + 1);
if (s->ptr == NULL) {
fprintf(stderr, "malloc() failed\n");
exit(-1);
}
s->ptr[0] = '\0';
}
/* Use the "writer" to accumulate text until done */
size_t accumulate(void *ptr, size_t size, size_t nmemb, struct return_string *s)
{
size_t new_len = s->len + size*nmemb;
s->ptr = realloc(s->ptr, new_len + 1);
if (s->ptr == NULL) {
fprintf(stderr, "realloc() failed\n");
exit(-1);
}
memcpy(s->ptr + s->len, ptr, size*nmemb);
s->ptr[new_len] = '\0';
s->len = new_len;
return size*nmemb;
}
int getContent()
{
//constants for reading the XML file
char *buffer = 0;
char finalRequest[200];
long length;
FILE *xmlFile = fopen("C:/Users/IEUser/Desktop/rs.xml", "r");
//constants for parsing XML
const char *HOSTSTART = "<Host>";
const char *HOSTEND = "</Host>";
const char *USERSTART = "<User>";
const char *USEREND = "</User>";
const char *PASSSTART = "<Pass encoding=\"base64\">";
const char *PASSEND = "</Pass>";
char *target_host = NULL, *target_user = NULL, *target_pass = NULL, *start, *end;
//read the xml file
if (xmlFile)
{
fseek(xmlFile, 0, SEEK_END);
length = ftell(xmlFile);
fseek(xmlFile, 0, SEEK_SET);
buffer = malloc(length);
if (buffer)
{
fread(buffer, 1, length, xmlFile);
}
fclose(xmlFile);
if (!buffer) exit(1);
}
start = buffer;
while (1) {
//get the HOST
if (start = strstr(start, HOSTSTART))
{
start += strlen(HOSTSTART);
if (end = strstr(start, HOSTEND))
{
target_host = (char *)malloc(end - start + 1);
memcpy(target_host, start, end - start);
target_host[end - start] = '\0';
}
}
else {
break;
}
//get the USER
if (start = strstr(start, USERSTART))
{
start += strlen(USERSTART);
if (end = strstr(start, USEREND))
{
target_user = (char *)malloc(end - start + 1);
memcpy(target_user, start, end - start);
target_user[end - start] = '\0';
}
}
//get the PASS
if (start = strstr(start, PASSSTART))
{
start += strlen(PASSSTART);
if (end = strstr(start, PASSEND))
{
target_pass = (char *)malloc(end - start + 1);
memcpy(target_pass, start, end - start);
target_pass[end - start] = '\0';
}
}
//send the requested string in the desired format to finalRequest[]
//k=host|user|password
strcpy(finalRequest, target_host);
strcat(finalRequest, "|");
strcat(finalRequest, target_user);
strcat(finalRequest, "|");
strcat(finalRequest, target_pass);
printf("%s", finalRequest);
printf("\n\n");
getKeyVal(finalRequest);
}
return 0;
}
int main()
{
getContent();
return 0;
}
