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From bri...@apache.org
Subject cvs commit: httpd-2.0 CHANGES
Date Wed, 04 Sep 2002 09:07:25 GMT
brianp      2002/09/04 02:07:25

  Modified:    modules/experimental mod_cache.c mod_cache.h
               .        CHANGES
  Log:
  Added optional support for caching streamed responses in mod_cache.
  Notes:
    * I've created a new config directive CacheMaxStreamingBuffer,
      to set the maximum amount of data that mod_cache will buffer
      per request if it hasn't yet seen an EOS.  The default is
      zero, which preserves the original behavior: cache only if
      the response has a known content-length or all the content
      is available in the first brigade passed to the CACHE_IN filter.
    * A big block of code in cache_in_filter() got wrapped in an
      if-statement in this change.  To make the diff more readable,
      I'm committing without indentation changes; a second commit
      will include (only) the indentation update.
  
  Revision  Changes    Path
  1.56      +118 -1    httpd-2.0/modules/experimental/mod_cache.c
  
  Index: mod_cache.c
  ===================================================================
  RCS file: /home/cvs/httpd-2.0/modules/experimental/mod_cache.c,v
  retrieving revision 1.55
  retrieving revision 1.56
  diff -u -r1.55 -r1.56
  --- mod_cache.c	1 Sep 2002 23:50:42 -0000	1.55
  +++ mod_cache.c	4 Sep 2002 09:07:25 -0000	1.56
  @@ -430,6 +430,7 @@
       void *scache = r->request_config;
       cache_request_rec *cache =
           (cache_request_rec *) ap_get_module_config(scache, &cache_module);
  +    apr_bucket *split_point = NULL;
   
   
       ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, f->r->server,
  @@ -450,6 +451,16 @@
           ap_set_module_config(r->request_config, &cache_module, cache);
       }
   
  +/* If we've previously processed and set aside part of this
  + * response, skip the cacheability checks
  + */
  +if (cache->saved_brigade != NULL) {
  +    exp = cache->exp;
  +    lastmod = cache->lastmod;
  +    info = cache->info;
  +}
  +else {
  +
       /*
        * Pass Data to Cache
        * ------------------
  @@ -579,6 +590,7 @@
           return ap_pass_brigade(f->next, in);
       }
       cache->in_checked = 1;
  +} /* if cache->saved_brigade==NULL */
   
       /* Set the content length if known.  We almost certainly do NOT want to
        * cache streams with unknown content lengths in the in-memory cache.
  @@ -599,6 +611,7 @@
                */
               apr_bucket *e;
               int all_buckets_here=0;
  +            int unresolved_length = 0;
               size=0;
               APR_BRIGADE_FOREACH(e, in) {
                   if (APR_BUCKET_IS_EOS(e)) {
  @@ -606,6 +619,7 @@
                       break;
                   }
                   if (APR_BUCKET_IS_FLUSH(e)) {
  +                    unresolved_length = 1;
                       continue;
                   }
                   if (e->length < 0) {
  @@ -615,7 +629,76 @@
               }
   
               if (!all_buckets_here) {
  -                size = -1;
  +                /* Attempt to set aside a copy of a partial response
  +                 * in hopes of caching it once the rest of the response
  +                 * is available.  There are special cases in which we
  +                 * don't try to set aside the content, though:
  +                 *   1. The brigade contains at least one bucket of
  +                 *      unknown length, such as a pipe or socket bucket.
  +                 *   2. The size of the response exceeds the limit set
  +                 *      by the CacheMaxStreamingBuffer  directive.
  +                 */
  +                if (unresolved_length ||
  +                    (cache->saved_size + size >
  +                     conf->max_streaming_buffer_size)) {
  +
  +                    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
  +                                 "cache: not caching streamed response for "
  +                                 "%s because length %s", url,
  +                                 (unresolved_length ?
  +                                  "cannot be determined" :
  +                                  "> CacheMaxStreamingBuffer"));
  +
  +                    if (cache->saved_brigade != NULL) {
  +                        apr_brigade_destroy(cache->saved_brigade);
  +                        cache->saved_brigade = NULL;
  +                        cache->saved_size = 0;
  +                    }
  +                    ap_remove_output_filter(f);
  +                    return ap_pass_brigade(f->next, in);
  +                }
  +
  +                /* Add a copy of the new brigade's buckets to the
  +                 * saved brigade.  The reason for the copy is so
  +                 * that we can output the new buckets immediately,
  +                 * rather than having to buffer up the entire
  +                 * response before sending anything.
  +                 */
  +                if (cache->saved_brigade == NULL) {
  +                    cache->saved_brigade =
  +                        apr_brigade_create(r->pool,
  +                                           r->connection->bucket_alloc);
  +                    cache->exp = exp;
  +                    cache->lastmod = lastmod;
  +                    cache->info = info;
  +                }
  +                APR_BRIGADE_FOREACH(e, in) {
  +                    apr_bucket *copy;
  +                    apr_bucket_copy(e, &copy);
  +                    APR_BRIGADE_INSERT_TAIL(cache->saved_brigade, copy);
  +                }
  +                cache->saved_size += size;
  +                ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
  +                             "cache: Response length still unknown, setting "
  +                             "aside content for url: %s", url);
  +
  +                return ap_pass_brigade(f->next, in);
  +            }
  +            else {
  +                /* Now that we've seen an EOS, it's appropriate
  +                 * to try caching the response.  If any content
  +                 * has been copied into cache->saved_brigade in
  +                 * previous passes through this filter, the
  +                 * content placed in the cache must be the
  +                 * concatenation of the saved brigade and the
  +                 * current brigade.
  +                 */
  +                if (cache->saved_brigade != NULL) {
  +                    split_point = APR_BRIGADE_FIRST(in);
  +                    APR_BRIGADE_CONCAT(cache->saved_brigade, in);
  +                    in = cache->saved_brigade;
  +                    size += cache->saved_size;
  +                }
               }
           }
       }
  @@ -658,6 +741,11 @@
       if (rv != OK) {
           /* Caching layer declined the opportunity to cache the response */
           ap_remove_output_filter(f);
  +        if (split_point) {
  +            apr_bucket_brigade *already_sent = in;
  +            in = apr_brigade_split(in, split_point);
  +            apr_brigade_destroy(already_sent);
  +        }
           return ap_pass_brigade(f->next, in);
       }
   
  @@ -754,6 +842,11 @@
       if (rv != APR_SUCCESS) {
           ap_remove_output_filter(f);
       }
  +    if (split_point) {
  +        apr_bucket_brigade *already_sent = in;
  +        in = apr_brigade_split(in, split_point);
  +        apr_brigade_destroy(already_sent);
  +    }
       return ap_pass_brigade(f->next, in);
   }
   
  @@ -784,6 +877,7 @@
       ps->no_last_mod_ignore = 0;
       ps->ignorecachecontrol = 0;
       ps->ignorecachecontrol_set = 0 ;
  +    ps->max_streaming_buffer_size = 0;
       return ps;
   }
   
  @@ -939,6 +1033,25 @@
       conf->complete_set = 1;
       return NULL;
   }
  +
  +static const char *set_max_streaming_buffer(cmd_parms *parms, void *dummy,
  +                                            const char *arg)
  +{
  +    cache_server_conf *conf;
  +    apr_off_t val;
  +    char *err;
  +
  +    conf =
  +        (cache_server_conf *)ap_get_module_config(parms->server->module_config,
  +                                                  &cache_module);
  +    val = (apr_off_t)strtol(arg, &err, 10);
  +    if (*err != 0) {
  +        return "CacheMaxStreamingBuffer value must be a percentage";
  +    }
  +    conf->max_streaming_buffer_size = val;
  +    return NULL;
  +}
  +
   static int cache_post_config(apr_pool_t *p, apr_pool_t *plog,
                                apr_pool_t *ptemp, server_rec *s)
   {
  @@ -985,6 +1098,10 @@
       AP_INIT_TAKE1("CacheForceCompletion", set_cache_complete, NULL, RSRC_CONF,
                     "Percentage of download to arrive for the cache to force "
                     "complete transfer"),
  +    AP_INIT_TAKE1("CacheMaxStreamingBuffer", set_max_streaming_buffer, NULL,
  +                  RSRC_CONF,
  +                  "Maximum number of bytes of content to buffer for "
  +                  "a streamed response"),
       {NULL}
   };
   
  
  
  
  1.32      +8 -0      httpd-2.0/modules/experimental/mod_cache.h
  
  Index: mod_cache.h
  ===================================================================
  RCS file: /home/cvs/httpd-2.0/modules/experimental/mod_cache.h,v
  retrieving revision 1.31
  retrieving revision 1.32
  diff -u -r1.31 -r1.32
  --- mod_cache.h	27 Aug 2002 19:22:45 -0000	1.31
  +++ mod_cache.h	4 Sep 2002 09:07:25 -0000	1.32
  @@ -179,6 +179,9 @@
       /** ignore client's requests for uncached responses */
       int ignorecachecontrol;
       int ignorecachecontrol_set;
  +    /* maximum amount of data to buffer on a streamed response where
  +     * we haven't yet seen EOS */
  +    apr_off_t max_streaming_buffer_size;
   } cache_server_conf;
   
   /* cache info information */
  @@ -237,6 +240,11 @@
       int fresh;				/* is the entitey fresh? */
       cache_handle_t *handle;		/* current cache handle */
       int in_checked;			/* CACHE_IN must cache the entity */
  +    apr_bucket_brigade *saved_brigade;  /* copy of partial response */
  +    apr_off_t saved_size;               /* length of saved_brigade */
  +    apr_time_t exp;                     /* expiration */
  +    apr_time_t lastmod;                 /* last-modified time */
  +    cache_info *info;                   /* current cache info */
   } cache_request_rec;
   
   
  
  
  
  1.913     +3 -0      httpd-2.0/CHANGES
  
  Index: CHANGES
  ===================================================================
  RCS file: /home/cvs/httpd-2.0/CHANGES,v
  retrieving revision 1.912
  retrieving revision 1.913
  diff -u -r1.912 -r1.913
  --- CHANGES	3 Sep 2002 15:54:45 -0000	1.912
  +++ CHANGES	4 Sep 2002 09:07:25 -0000	1.913
  @@ -1,5 +1,8 @@
   Changes with Apache 2.0.41
   
  +  *) mod_cache: added support for caching streamed responses (proxy,
  +     CGI, etc) with optional CacheMaxStreamingBuffer setting [Brian Pane]
  +
     *) Add image/x-icon to httpd.conf PR 10993.
        [Ian Holsman, Peter Bieringer <pb@bieringer.de>]
   
  
  
  

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