gistfile1.c

#include "lwan.h"
#include "lwan-cache.h"
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>

struct file_info_t {
	struct cache_entry_t base;
	struct {
		char *content;
		size_t size;
	} metadata;
	char *key;
};

static lwan_t l;
static struct cache_t *cache;

// ham nay load file tu dia len memory
static size_t ae_load_file_to_memory(const char *filename, char **result) {
    size_t size = 0;
    FILE *f = fopen(filename, "rb");
    if (f == NULL) {
        *result = NULL;
        return 0; // -1 means file opening fail 
    }

    fseek(f, 0, SEEK_END);
    size = (size_t) ftell(f);
    fseek(f, 0, SEEK_SET);

    *result = (char *) malloc(size);
    if (*result) {
        if (size != fread(*result, 1, size, f)) {
            free(*result);
            *result = NULL;
        }
    }

    fclose(f);
    return size;
}

// handler trong file config 
lwan_http_status_t
static_handler(lwan_request_t *request,
        lwan_response_t *response,
        void *data __attribute__((unused))) {
    struct file_info_t *fi;
    fi = (struct file_info_t*) cache_coro_get_and_ref_entry(cache,
            request->conn->coro, "love.jpg");
    if (!fi)
        return HTTP_NOT_FOUND;
    response->mime_type = lwan_determine_mime_type_for_file_name("love.jpg");
    // tra ra cho browser

    lwan_status_info("loaded from cache: key=[%s], metadata.size=[%zu]",
        fi->key, fi->metadata.size);

    strbuf_set_static(response->buffer, fi->metadata.content, fi->metadata.size);
    return HTTP_OK;
}

// read file and initialize cache object
static struct cache_entry_t *
create_fileinfo(const char *file_path,
        void *context __attribute__((unused))) {
    struct file_info_t *fi = calloc(1, sizeof (struct file_info_t));
    if (!fi)
        return NULL;
    
    char *content = NULL;
    size_t file_size = ae_load_file_to_memory(file_path, &content);

    lwan_status_info("loaded from disk: key=[%s], metadata.size=[%zu]", file_path, file_size);

    if (content && file_size) {
        fi->key = strdup(file_path);
        fi->metadata.content = content;
        fi->metadata.size = file_size;
        return (struct cache_entry_t *) fi;
    }

    return NULL;
}

// callback to destroy cache
static void
destroy_fileinfo(struct cache_entry_t *entry,
        void *context __attribute__((unused))) {
    struct file_info_t *fileinfo = (struct file_info_t *) entry;
    if (!fileinfo) return;
    free(fileinfo->metadata.content);
    free(fileinfo->key);
    free(fileinfo);
}

int
main(void)
{
    lwan_init(&l);

    cache = cache_create(create_fileinfo, destroy_fileinfo, NULL, 16);

    lwan_main_loop(&l);
    lwan_shutdown(&l);
    
    cache_destroy(cache);

    return 0;
}