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From Glen Parker <glene...@nwlink.com>
Subject mod_proxy/2277: PATCH: cache completion of partially loaded documents
Date Mon, 25 May 1998 08:24:17 GMT

>Number:         2277
>Category:       mod_proxy
>Synopsis:       PATCH: cache completion of partially loaded documents
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    apache
>State:          open
>Class:          change-request
>Submitter-Id:   apache
>Arrival-Date:   Mon May 25 01:30:00 PDT 1998
>Last-Modified:
>Originator:     glenebob@nwlink.com
>Organization:
apache
>Release:        1.3b6
>Environment:
Winnt4.0, SP3
Linux, Redhat 5.0

Based on 1.3b6 standard tarball, no patches.
>Description:
patch
>How-To-Repeat:
patch
>Fix:
This patch will cause the proxy module to finish loading a file to the
cache in the event that the client cancels the transfer, provided that
the configured percentage of the file has already been transfered.
It works for http transfers only.

The new httpd.conf directive is:
CacheForceCompletion <percentage>

which can be a number between 1 and 100, or 0 to use the default, 90%.
I like to use 70 or 80 here.  Obviously, this could be dangerous, I'd
recommend a number AT LEAST over 50 here, otherwise you may bring your
Internet connection to its knees.

I have compiled this on WinNT 4.0 and Redhat Linux 5.0 (2.0.32 kernel).
I tested *briefly* on NT, and I'm using it on 3 different Linux servers
with good results.

There's actually two patches, one for the source, and the other for the
html docs.

Affected files in src/modules/proxy are:
mod_proxy.h
mod_proxy.c
proxy_cache.c
proxy_http.c
proxy_ftp.c
proxy_util.c

Affected files in htdocs/manual/mod are:
directives.html
mod_proxy.html

PLEASE! send email to glenebob@nwlink.com if you have problems or comments.

So, here they are...

=== source patch ========================================================

diff -C3 apache_1.3b6/src/modules/proxy.orig/mod_proxy.c apache_1.3b6/src/modules/proxy/mod_proxy.c
*** apache_1.3b6/src/modules/proxy.orig/mod_proxy.c	Sat Apr 11 05:00:39 1998
--- apache_1.3b6/src/modules/proxy/mod_proxy.c	Sun May 24 17:40:20 1998
***************
*** 406,411 ****
--- 406,412 ----
      /* at these levels, the cache can have 2^18 directories (256,000)  */
      ps->cache.dirlevels = 3;
      ps->cache.dirlength = 1;
+     ps->cache.cache_completion = DEFAULT_CACHE_COMPLETION;
  
      return ps;
  }
***************
*** 742,747 ****
--- 743,763 ----
      return NULL;
  }
  
+ static const char*
+     set_cache_completion(cmd_parms *parms, void *dummy, char *arg)
+ {
+     proxy_server_conf *psf =
+     ap_get_module_config(parms->server->module_config, &proxy_module);
+     int s = atoi(arg);
+     if (s > 100 || s < 0) {
+ 	return "CacheForceCompletion must be <= 100 perent, or 0 for system default.";
+     }
+ 
+     if (s > 0)
+       psf->cache.cache_completion = ((float)s / 100);
+     return NULL;    
+ }
+ 
  static const handler_rec proxy_handlers[] =
  {
      {"proxy-server", proxy_handler},
***************
*** 784,789 ****
--- 800,807 ----
       "The number of characters in subdirectory names"},
      {"NoCache", set_cache_exclude, NULL, RSRC_CONF, ITERATE,
       "A list of names, hosts or domains for which caching is *not* provided"},
+     {"CacheForceCompletion", set_cache_completion, NULL, RSRC_CONF, TAKE1,
+      "Force a http cache completion after this percentage is loaded"},
      {NULL}
  };
  
diff -C3 apache_1.3b6/src/modules/proxy.orig/mod_proxy.h apache_1.3b6/src/modules/proxy/mod_proxy.h
*** apache_1.3b6/src/modules/proxy.orig/mod_proxy.h	Sat Apr 11 05:00:39 1998
--- apache_1.3b6/src/modules/proxy/mod_proxy.h	Sun May 24 17:44:48 1998
***************
*** 184,189 ****
--- 184,190 ----
  #define DEFAULT_CACHE_MAXEXPIRE SEC_ONE_DAY
  #define DEFAULT_CACHE_EXPIRE    SEC_ONE_HR
  #define DEFAULT_CACHE_LMFACTOR (0.1)
+ #define DEFAULT_CACHE_COMPLETION (0.9)
  
  /* static information about the local cache */
  struct cache_conf {
***************
*** 195,200 ****
--- 196,202 ----
      int gcinterval;		/* garbage collection interval, in seconds */
      int dirlevels;		/* Number of levels of subdirectories */
      int dirlength;		/* Length of subdirectory names */
+     float cache_completion;	/* Force cache completion after this point */
  };
  
  typedef struct {
***************
*** 232,237 ****
--- 234,241 ----
      unsigned int len;		/* content length */
      char *protocol;		/* Protocol, and major/minor number, e.g. HTTP/1.1 */
      int status;			/* the status of the cached file */
+     unsigned int written;	/* total *content* bytes written to cache */
+     float cache_completion;	/* specific to this request */
      char *resp_line;		/* the whole status like (protocol, code + message) */
      array_header *hdrs;		/* the HTTP headers of the file */
  };
diff -C3 apache_1.3b6/src/modules/proxy.orig/proxy_cache.c apache_1.3b6/src/modules/proxy/proxy_cache.c
*** apache_1.3b6/src/modules/proxy.orig/proxy_cache.c	Wed Apr 15 10:09:29 1998
--- apache_1.3b6/src/modules/proxy/proxy_cache.c	Sat May 23 17:36:55 1998
***************
*** 551,557 ****
--- 551,560 ----
  	}
      }
      if (cachefp == NULL)
+ /* fixed?  in this case, we want to get the headers from the remote server
+    it will be handled later if we don't do this (I hope ;-)
  	c->hdrs = ap_make_array(r->pool, 2, sizeof(struct hdr_entry));
+ */
      /* FIXME: Shouldn't we check the URL somewhere? */
      now = time(NULL);
  /* Ok, have we got some un-expired data? */
***************
*** 886,892 ****
--- 889,898 ----
      if (c->fp == NULL)
  	return;
  
+ /* don't care how much was sent, but rather how much was written to cache
      ap_bgetopt(c->req->connection->client, BO_BYTECT, &bc);
+  */
+     bc = c->written;
  
      if (c->len != -1) {
  /* file lengths don't match; don't cache it */
***************
*** 896,906 ****
  	    return;
  	}
      }
      else if (c->req->connection->aborted) {
! 	ap_pclosef(c->req->pool, c->fp->fd);	/* no need to flush */
  	unlink(c->tempfile);
  	return;
      }
      else {
  /* update content-length of file */
  	char buff[9];
--- 902,914 ----
  	    return;
  	}
      }
+ /* don't care if aborted, cache it if fully retrieved from host!
      else if (c->req->connection->aborted) {
! 	ap_pclosef(c->req->pool, c->fp->fd);	/ no need to flush /
  	unlink(c->tempfile);
  	return;
      }
+ */
      else {
  /* update content-length of file */
  	char buff[9];
diff -C3 apache_1.3b6/src/modules/proxy.orig/proxy_ftp.c apache_1.3b6/src/modules/proxy/proxy_ftp.c
*** apache_1.3b6/src/modules/proxy.orig/proxy_ftp.c	Sun May 24 15:46:11 1998
--- apache_1.3b6/src/modules/proxy/proxy_ftp.c	Sun May 24 17:35:47 1998
***************
*** 990,995 ****
--- 990,997 ----
      r->status_line = "200 OK";
  
      resp_hdrs = ap_make_array(p, 2, sizeof(struct hdr_entry));
+     c->hdrs = resp_hdrs;
+ 
      if (parms[0] == 'd')
  	ap_proxy_add_header(resp_hdrs, "Content-Type", "text/html", HDR_REP);
      else {
***************
*** 1021,1028 ****
--- 1023,1033 ----
  	ap_bclose(f);
  	return i;
      }
+ 
      cache = c->fp;
  
+     c->hdrs = resp_hdrs;
+ 
      if (!pasvmode) {		/* wait for connection */
  	ap_hard_timeout("proxy ftp data connect", r);
  	clen = sizeof(struct sockaddr_in);
***************
*** 1087,1095 ****
      r->sent_bodyct = 1;
  /* send body */
      if (!r->header_only) {
! 	if (parms[0] != 'd')
  	    ap_proxy_send_fb(data, r, cache, c);
! 	else
  	    send_dir(data, r, cache, c, url);
  
  	if (rc == 125 || rc == 150)
--- 1092,1102 ----
      r->sent_bodyct = 1;
  /* send body */
      if (!r->header_only) {
! 	if (parms[0] != 'd') {
! /* we need to set this for ap_proxy_send_fb()... */
! 	    c->cache_completion = 0;
  	    ap_proxy_send_fb(data, r, cache, c);
! 	} else
  	    send_dir(data, r, cache, c, url);
  
  	if (rc == 125 || rc == 150)
diff -C3 apache_1.3b6/src/modules/proxy.orig/proxy_http.c apache_1.3b6/src/modules/proxy/proxy_http.c
*** apache_1.3b6/src/modules/proxy.orig/proxy_http.c	Sat Apr 11 05:00:40 1998
--- apache_1.3b6/src/modules/proxy/proxy_http.c	Sun May 24 17:52:36 1998
***************
*** 369,374 ****
--- 369,376 ----
  	resp_hdrs = ap_make_array(p, 2, sizeof(struct hdr_entry));
      }
  
+     c->hdrs = resp_hdrs;
+ 
      ap_kill_timeout(r);
  
  /*
***************
*** 457,464 ****
  /* send body */
  /* if header only, then cache will be NULL */
  /* HTTP/1.0 tells us to read to EOF, rather than content-length bytes */
!     if (!r->header_only)
  	ap_proxy_send_fb(f, r, cache, c);
  
      ap_proxy_cache_tidy(c);
  
--- 459,469 ----
  /* send body */
  /* if header only, then cache will be NULL */
  /* HTTP/1.0 tells us to read to EOF, rather than content-length bytes */
!     if (!r->header_only) {
! /* we need to set this for ap_proxy_send_fb()... */
! 	c->cache_completion = conf->cache.cache_completion;
  	ap_proxy_send_fb(f, r, cache, c);
+     }
  
      ap_proxy_cache_tidy(c);
  
diff -C3 apache_1.3b6/src/modules/proxy.orig/proxy_util.c apache_1.3b6/src/modules/proxy/proxy_util.c
*** apache_1.3b6/src/modules/proxy.orig/proxy_util.c	Sat Apr 11 05:00:40 1998
--- apache_1.3b6/src/modules/proxy/proxy_util.c	Sun May 24 18:26:21 1998
***************
*** 442,453 ****
  
  long int ap_proxy_send_fb(BUFF *f, request_rec *r, BUFF *f2, struct cache_req *c)
  {
      char buf[IOBUFSIZE];
!     long total_bytes_sent;
      register int n, o, w;
      conn_rec *con = r->connection;
  
!     total_bytes_sent = 0;
  
  #ifdef CHARSET_EBCDIC
      /* The cache copy is ASCII, not EBCDIC, even for text/html) */
--- 442,457 ----
  
  long int ap_proxy_send_fb(BUFF *f, request_rec *r, BUFF *f2, struct cache_req *c)
  {
+     int  ok = 1;
      char buf[IOBUFSIZE];
!     long total_bytes_rcv;
      register int n, o, w;
      conn_rec *con = r->connection;
+     int alt_to = 1;
  
!     total_bytes_rcv = 0;
!     if (c)
!         c->written = 0;
  
  #ifdef CHARSET_EBCDIC
      /* The cache copy is ASCII, not EBCDIC, even for text/html) */
***************
*** 461,470 ****
       * it is unsafe to do a soft_timeout here, at least until the proxy
       * has its own timeout handler which can set both buffers to EOUT.
       */
      ap_hard_timeout("proxy send body", r);
  
-     while (!con->aborted && f != NULL) {
  	n = ap_bread(f, buf, IOBUFSIZE);
  	if (n == -1) {		/* input error */
  	    if (f2 != NULL)
  		f2 = ap_proxy_cache_error(c);
--- 465,507 ----
       * it is unsafe to do a soft_timeout here, at least until the proxy
       * has its own timeout handler which can set both buffers to EOUT.
       */
+ 
+     ap_kill_timeout(r);
+ 
+ #ifdef WIN32
+     /* works fine under win32, so leave it */
      ap_hard_timeout("proxy send body", r);
+     alt_to = 0;
+ #else
+     /* CHECKME! Since hard_timeout won't work in unix on sends with partial
+      * cache completion, we have to alternate between hard_timeout
+      * for reads, and soft_timeout for send.  This is because we need
+      * to get a return from ap_bwrite to be able to continue caching.
+      * BUT, if we *can't* continue anyway, just use hard_timeout.
+      */
+ 
+     if (c) {
+         if (c->len <= 0 || c->cache_completion == 1) {
+             ap_hard_timeout("proxy send body", r);
+             alt_to = 0;
+         }
+     } else {
+         ap_hard_timeout("proxy send body", r);
+         alt_to = 0;
+     }
+ #endif
+ 
+     while (ok && f != NULL) {
+         if (alt_to)
+             ap_hard_timeout("proxy send body", r);
  
  	n = ap_bread(f, buf, IOBUFSIZE);
+ 
+         if (alt_to)
+             ap_kill_timeout(r);
+         else
+             ap_reset_timeout(r);
+ 
  	if (n == -1) {		/* input error */
  	    if (f2 != NULL)
  		f2 = ap_proxy_cache_error(c);
***************
*** 473,506 ****
  	if (n == 0)
  	    break;		/* EOF */
  	o = 0;
! 	total_bytes_sent += n;
  
! 	if (f2 != NULL)
! 	    if (ap_bwrite(f2, buf, n) != n)
! 		f2 = ap_proxy_cache_error(c);
! 
! 	while (n && !con->aborted) {
! 	    w = ap_bwrite(con->client, &buf[o], n);
! 	    if (w <= 0) {
! 		if (f2 != NULL) {
! 		    ap_pclosef(c->req->pool, c->fp->fd);
! 		    c->fp = NULL;
! 		    f2 = NULL;
! 		    con->aborted = 1;
! 		    unlink(c->tempfile);
! 		}
! 		break;
! 	    }
! 	    ap_reset_timeout(r);	/* reset timeout after successful write */
! 	    n -= w;
! 	    o += w;
! 	}
      }
      if (!con->aborted)
  	ap_bflush(con->client);
  
      ap_kill_timeout(r);
!     return total_bytes_sent;
  }
  
  /*
--- 510,566 ----
  	if (n == 0)
  	    break;		/* EOF */
  	o = 0;
! 	total_bytes_rcv += n;
  
!         if (f2 != NULL) {
!             if (ap_bwrite(f2, &buf[0], n) != n) {
!                 f2 = ap_proxy_cache_error(c);
!             } else {
!                 c->written += n;
!             }
!         }
! 
!         while (n && !con->aborted) {
!             if (alt_to)
!                 ap_soft_timeout("proxy send body", r);
! 
!             w = ap_bwrite(con->client, &buf[o], n);
! 
!             if (alt_to)
!                 ap_kill_timeout(r);
!             else
!                 ap_reset_timeout(r);
! 
!             if (w <= 0) {
!                 if (f2 != NULL) {
!                     /* when a send failure occurs, we need to decide
!                      * whether to continue loading and caching the
!                      * document, or to abort the whole thing
!                      */
!                     ok = (c->len > 0) &&
!                          (c->cache_completion > 0) &&
!                          (c->len * c->cache_completion < total_bytes_rcv);
! 
!                     if (! ok) {
!                         ap_pclosef(c->req->pool, c->fp->fd);
!                         c->fp = NULL;
!                         f2 = NULL;
!                         unlink(c->tempfile);
!                     }
!                 }
!                 con->aborted = 1;
!                 break;
!             }
!             n -= w;
!             o += w;
!         }
      }
+ 
      if (!con->aborted)
  	ap_bflush(con->client);
  
      ap_kill_timeout(r);
!     return total_bytes_rcv;
  }
  
  /*

=========================================================================

=== documentation patch =================================================

diff -C3 apache_1.3b6/htdocs/manual/mod.orig/directives.html apache_1.3b6/htdocs/manual/mod/directives.html
*** apache_1.3b6/htdocs/manual/mod.orig/directives.html	Sun May 24 18:38:45 1998
--- apache_1.3b6/htdocs/manual/mod/directives.html	Sun May 24 19:31:11 1998
***************
*** 76,81 ****
--- 76,82 ----
  <LI><A HREF="mod_proxy.html#cachedefaultexpire">CacheDefaultExpire</A>
  <LI><A HREF="mod_proxy.html#cachedirlength">CacheDirLength</A>
  <LI><A HREF="mod_proxy.html#cachedirlevels">CacheDirLevels</A>
+ <LI><A HREF="mod_proxy.html#cacheforcecompletion">CacheForceCompletion</A>
  <LI><A HREF="mod_proxy.html#cachegcinterval">CacheGcInterval</A>
  <LI><A HREF="mod_proxy.html#cachelastmodifiedfactor">CacheLastModifiedFactor</A>
  <LI><A HREF="mod_proxy.html#cachemaxexpire">CacheMaxExpire</A>
diff -C3 apache_1.3b6/htdocs/manual/mod.orig/mod_proxy.html apache_1.3b6/htdocs/manual/mod/mod_proxy.html
*** apache_1.3b6/htdocs/manual/mod.orig/mod_proxy.html	Sun May 24 18:39:27 1998
--- apache_1.3b6/htdocs/manual/mod/mod_proxy.html	Sun May 24 18:58:00 1998
***************
*** 62,67 ****
--- 62,68 ----
  <LI><A HREF="#cachegcinterval">CacheGcInterval</A>
  <LI><A HREF="#cachedirlevels">CacheDirLevels</A>
  <LI><A HREF="#cachedirlength">CacheDirLength</A>
+ <LI><A HREF="#cacheforcecompletion">CacheForceCompletion</A>
  <LI><A
  HREF="#nocache">NoCache</A>
  </UL>
***************
*** 555,560 ****
--- 556,602 ----
    NoProxy         .mycompany.com 192.168.112.0/21 
    ProxyDomain     .mycompany.com
  </PRE>
+ 
+ <HR>
+ 
+ <H2><A NAME="cacheforcecompletion">CacheForceCompletion</A></H2>
+ <A
+  HREF="directive-dict.html#Syntax"
+  REL="Help"
+ ><STRONG>Syntax:</STRONG></A> CacheForceCompletion <EM>&lt;percentage&gt;</EM><BR>
+ <A
+  HREF="directive-dict.html#Default"
+  REL="Help"
+ ><STRONG>Default:</STRONG></A> <EM>90</EM><BR>
+ <A
+  HREF="directive-dict.html#Context"
+  REL="Help"
+ ><STRONG>Context:</STRONG></A> server config, virtual host<BR>
+ <A
+  HREF="directive-dict.html#Override"
+  REL="Help"
+ ><STRONG>Override:</STRONG></A> <EM>Not applicable</EM><BR>
+ <A
+  HREF="directive-dict.html#Status"
+  REL="Help"
+ ><STRONG>Status:</STRONG></A> Base<BR>
+ <A
+  HREF="directive-dict.html#Module"
+  REL="Help"
+ ><STRONG>Module:</STRONG></A> mod_proxy<BR>
+ <A
+  HREF="directive-dict.html#Compatibility"
+  REL="Help"
+ ><STRONG>Compatibility:</STRONG></A> CacheForceCompletion is only available
in
+ Apache 1.3 and later.<P>
+ 
+ If an http transfer that is being cached is cancelled, the proxy module will
+ complete the transfer to cache if more than the percentage specified has already
+ been transferred.<P>
+ 
+ This is a percentage, and must be a number between 1 and 100, or 0 to use
+ the default.  100 will cause a document to be cached only if the transfer
+ was allowed to complete.  A number between 60 and 90 is recommended.
  
  <HR>
  
=========================================================================
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