gistfile1.c

backend default {
  .host = "127.0.0.1";
  .port = "3000";
}

C{
  #include <dlfcn.h>
  typedef int twitter_is_fresh_t(char *, char *);

  static twitter_is_fresh_t *twitter_is_fresh_ptr;
  
  void twitter_init() {
    if (!twitter_is_fresh_ptr) {
      void *library;
      library = dlopen("freshyfresh.so", RTLD_NOW);
      twitter_is_fresh_ptr = (twitter_is_fresh_t *)dlsym(library, "twitter_is_fresh");
    }
  }

  int twitter_is_fresh(char *generation_key, char *etag) {
    twitter_init();
    return twitter_is_fresh_ptr(generation_key, etag);
  }
}C

sub vcl_recv {
   if (req.request != "GET" && req.request != "HEAD") {
     pass;
   }
    
  if (req.http.Authorization) {
    lookup;
  }
}

sub vcl_hash {
   set req.hash += req.url;
   set req.hash += req.http.Authorization;
   hash;
}

sub vcl_hit {
  if (!obj.cacheable) {
    pass;
  }
  
  call check_freshness;
  
  deliver;
}

sub check_freshness {
  C{
    int fresh;
    char *etag;
    char *generation_key;
    
    etag = VRT_GetHdr(sp, HDR_OBJ, "\005ETag:");
    generation_key = VRT_GetHdr(sp, HDR_OBJ, "\021X-Generation-Key:");
    
    if (!twitter_is_fresh(generation_key, etag)) {
      VRT_l_obj_ttl(sp, (0 * 1));
      VRT_done(sp, VCL_RET_PASS);
    }
    free(etag);
    free(generation_key);
  }C
}

sub vcl_fetch {
  deliver;
}