gistfile1.txt

C{
  #include <dlfcn.h>
  #include <stdlib.h>
  #include <stdio.h>
  #include <string.h>
  #include <assert.h>

  typedef int twitter_is_fresh_t(char *, char *);

  static twitter_is_fresh_t *twitter_is_fresh_ptr = NULL;
  
  void twitter_init() { 
    char *error;
    void *library = NULL;

    if (!twitter_is_fresh_ptr) {
      library = dlopen("/usr/local/lib/freshyfresh.so", RTLD_NOW);
      if (!library) {
        fprintf (stderr, "Could not open library: %s\n", dlerror());
        exit(1);
      }

      dlerror();
      twitter_is_fresh_ptr = (twitter_is_fresh_t *)dlsym(library, "twitter_is_fresh");
      if ((error = dlerror()) != NULL) {
        fprintf(stderr, "Could not resolve function pointer: %s\n", error);
        exit(1);
      }
    }
  }

  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.restarts > 1) {
    // set req.grace = 0s;
  // } else {
    set req.grace = 5s;
  // }
  
  if (req.http.Authorization) {
    lookup;
  }
}

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

sub vcl_fetch {
    if (!obj.cacheable) {
      pass;
    }
    set obj.grace = 5s;
    
    deliver;
}

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

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

sub vcl_fetch {
  deliver;
}