Ulrond
commented
1 month ago functionality to support reading from either a local file or a remote one, using the curl library ->
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <curl/curl.h>
// Function to get the size of a remote file
long get_remote_file_size(const char *url) {
CURL *curl;
CURLcode res;
double filesize = 0.0;
curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, url);
curl_easy_setopt(curl, CURLOPT_NOBODY, 1L);
curl_easy_setopt(curl, CURLOPT_HEADER, 1L);
curl_easy_setopt(curl, CURLOPT_FILETIME, 1L);
res = curl_easy_perform(curl);
if(res == CURLE_OK) {
res = curl_easy_getinfo(curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &filesize);
if((res == CURLE_OK) && (filesize > 0.0)) {
curl_easy_cleanup(curl);
return (long)filesize;
}
}
curl_easy_cleanup(curl);
}
return -1;
}
// Function to get the size of a local file
long get_local_file_size(const char *filename) {
FILE *file = fopen(filename, "rb");
if(file == NULL) {
perror("Error opening file");
return -1;
}
fseek(file, 0, SEEK_END);
long filesize = ftell(file);
fclose(file);
return filesize;
}
// Callback function to write data into a buffer
size_t write_data(void *ptr, size_t size, size_t nmemb, void *data) {
size_t total_size = size * nmemb;
char **buffer = (char **)data;
*buffer = realloc(*buffer, strlen(*buffer) + total_size + 1);
strncat(*buffer, ptr, total_size);
return total_size;
}
// Function to download a file using libcurl and store its content in a buffer
int download_file(const char *url, char **buffer) {
CURL *curl;
CURLcode res;
*buffer = malloc(1);
**buffer = '\0';
curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, url);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, buffer);
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
if(res != CURLE_OK) {
fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
free(*buffer);
return -1;
}
return 0;
}
free(*buffer);
return -1;
}
// Function to read content from a local file into a buffer
int read_local_file(const char *filename, char **buffer) {
long filesize = get_local_file_size(filename);
if (filesize == -1) {
return -1;
}
FILE *file = fopen(filename, "rb");
if (file == NULL) {
perror("Error opening file");
return -1;
}
*buffer = malloc(filesize + 1);
if (*buffer == NULL) {
perror("Error allocating memory");
fclose(file);
return -1;
}
fread(*buffer, 1, filesize, file);
(*buffer)[filesize] = '\0'; // Null-terminate the buffer
fclose(file);
return 0;
}
// Unified function to read from either a URL or a local file
int ut_read(const char *path, char **buffer) {
// Check if the path is a URL (simple check for http:// or https://)
if (strstr(path, "http://") || strstr(path, "https://")) {
long filesize = get_remote_file_size(path);
if (filesize == -1) {
fprintf(stderr, "Failed to get remote file size.\n");
return -1;
}
return download_file(path, buffer);
} else {
return read_local_file(path, buffer);
}
}
int main(void) {
const char *input = "https://example.com/file.txt"; // or "local_file.txt"
char *buffer = NULL;
if (ut_read(input, &buffer) == 0) {
printf("File content:\n%s\n", buffer);
free(buffer); // Don't forget to free the allocated memory
} else {
printf("Failed to read file.\n");
}
return 0;
}
While libfyaml itself doesn't directly support including other YAML files. We need to create a mechanism for including files.
Here's an approach that may work.
1. Manual Inclusion and Parsing:
!include).2. Preprocessing:
3. Custom Tag Support:
!include) for including other files.Example (Manual Inclusion):