@@ -31,6 +31,7 @@

 #define BUFBLOCKBLOCK 256

 #define POSTBLOCK 16

 #define ALIVETIMEOUT 15

+#define MAXETAGSIZE 127

 typedef struct wk_post {

         char *name;

@@ -67,6 +68,7 @@ typedef struct wk_client {

         int pendingpost;

         int inpostvar;

         int cookiebufid;

+        char etag[MAXETAGSIZE+1];

         time_t lastio;

 } wk_client;

@@ -117,6 +119,7 @@ static int wk_postadd(_wk *web, wk_client *client,char *varname, char *tofile);

 static int wk_postset(_wk *web, wk_client *client,char *varname, char *data, int datalen);

 static char *wk_postget(_wk *web, wk_client *client,char *varname, int *isfile);

 static int wk_postfree(_wk *web, wk_client *client);

+static int wk_etagnotmodified(_wk *web, wk_client *client);

 #ifdef WK_DEBUG_IO

 #define DEBUG_IN_PRE { int sbp=sbuf_count(in);

@@ -438,6 +441,22 @@ wk_serve_cookieadd(wk *paramweb, int connid, char *cookiename, char *value, char

         return(0);

 }

+int

+wk_serve_etagset(wk *paramweb, int connid, char *etag)

+{

+        _wk *web=(_wk *)paramweb;

+        wk_client *client;

+        if(web==NULL)

+                return(-1);

+        if((client=wk_clientget(web,connid))==NULL)

+                return(-1);

+        if(etag!=NULL) {

+                strncpy(client->etag,etag,sizeof(client->etag));

+                client->etag[sizeof(client->etag)-1]='\0';

+        } else

+                client->etag[0]='\0';

+        return(0);

+}

 int

 wk_serve_buffer_as_file(wk *paramweb, int connid, void *data, int datalen, const char *mime)

@@ -447,28 +466,44 @@ wk_serve_buffer_as_file(wk *paramweb, int connid, void *data, int datalen, const

         wk_client *client;

         char buf[256];

         sbuf *cookiebuf;

+        int cachedetag;

         if(web==NULL)

                 return(-1);

         if((client=wk_clientget(web,connid))==NULL)

                 return(-1);

-        wk_writestr((wk *)web,connid,"HTTP/1.0 200 OK\r\n");

+        cachedetag=(wk_etagnotmodified(web,client)==0)?1:0;

+        if(!cachedetag)

+                wk_writestr((wk *)web,connid,"HTTP/1.0 200 OK\r\n");

+        else

+                wk_writestr((wk *)web,connid,"HTTP/1.1 304 Not modified\r\n");

         if(client->cookiebufid!=-1 && (cookiebuf=wk_sbufget((wk *)web,client->cookiebufid))!=NULL) {

                 if(wk_write((wk *)web,connid,sbuf_getbytes(cookiebuf,sbuf_count(cookiebuf)),sbuf_count(cookiebuf))==-1 ||

                   sbuf_count(cookiebuf)!=0)

                         return(-1); /* insufficient memory */

                 wk_sbufrelease((wk *)web,client->cookiebufid),client->cookiebufid=-1;

         }

-        sprintf(buf,"Content-Length: %i\r\n",datalen);

-        wk_writestr((wk *)web,connid,buf);

-        if(mime!=NULL && strlen(mime)<(sizeof(buf)-sizeof(strcontenttype)-3))

-                sprintf(buf,"%s%s\r\n",strcontenttype,mime);

-        else

-                sprintf(buf,"%s%s\r\n",strcontenttype,"application/octet-stream");

-        wk_writestr((wk *)web,connid,buf);

+        if(!cachedetag) {

+                if(client->etag[0]!='\0') {

+                        sprintf(buf,"ETag: \"%s\"\r\n",client->etag);

+                        client->etag[0]='\0';

+                        wk_writestr((wk *)web,connid,buf);

+                }

+                sprintf(buf,"Content-Length: %i\r\n",datalen);

+                wk_writestr((wk *)web,connid,buf);

+                if(mime!=NULL && strlen(mime)<(sizeof(buf)-sizeof(strcontenttype)-3))

+                        sprintf(buf,"%s%s\r\n",strcontenttype,mime);

+                else

+                        sprintf(buf,"%s%s\r\n",strcontenttype,"application/octet-stream");

+                wk_writestr((wk *)web,connid,buf);

+        } else {

+                wk_writestr((wk *)web,connid,"Content-Length: 0\r\n");

+        }

         if(client->keepalive)

                 wk_writestr((wk *)web,connid,"Connection: keep-alive\r\n");

         wk_writestr((wk *)web,connid,"\r\n");

-        return(wk_write((wk *)web,connid,data,datalen));

+        if(!cachedetag)

+                return(wk_write((wk *)web,connid,data,datalen));

+        return(0);

 }

 int

@@ -480,33 +515,47 @@ wk_serve_file(wk *paramweb, int connid, char *filename, const char *mime)

         char buf[256];

         sbuf *cookiebuf;

         struct stat st;

+        int cachedetag;

         if(web==NULL || filename==NULL)

                 return(-1);

         if((client=wk_clientget(web,connid))==NULL)

                 return(-1);

         if(client->fdtoserve!=-1)

                 close(client->fdtoserve),client->fdtoserve=-1;

-        if((client->fdtoserve=open(filename,O_RDONLY))==-1) {

-                wk_serve_error((wk *)web,connid,wkerr_notfound);

-                return(-1);

-        }

-        wk_writestr((wk *)web,connid,"HTTP/1.1 200 OK\r\n");

+        cachedetag=(wk_etagnotmodified(web,client)==0)?1:0;

+        if(!cachedetag) {

+                if((client->fdtoserve=open(filename,O_RDONLY))==-1) {

+                        wk_serve_error((wk *)web,connid,wkerr_notfound);

+                        return(-1);

+                }

+                wk_writestr((wk *)web,connid,"HTTP/1.0 200 OK\r\n");

+        } else

+                wk_writestr((wk *)web,connid,"HTTP/1.1 304 Not modified\r\n");

         if(client->cookiebufid!=-1 && (cookiebuf=wk_sbufget((wk *)web,client->cookiebufid))!=NULL) {

                 if(wk_write((wk *)web,connid,sbuf_getbytes(cookiebuf,sbuf_count(cookiebuf)),sbuf_count(cookiebuf))==-1 ||

                   sbuf_count(cookiebuf)!=0)

                         return(-1); /* insufficient memory */

                 wk_sbufrelease((wk *)web,client->cookiebufid),client->cookiebufid=-1;

         }

-        if(fstat(client->fdtoserve,&st)==0) {

-                sprintf(buf,"Content-Length: %lld\r\n",(long long)st.st_size);

+        if(!cachedetag) {

+                if(client->etag[0]!='\0') {

+                        sprintf(buf,"ETag: \"%s\"\r\n",client->etag);

+                        client->etag[0]='\0';

+                        wk_writestr((wk *)web,connid,buf);

+                }

+                if(fstat(client->fdtoserve,&st)==0) {

+                        sprintf(buf,"Content-Length: %lld\r\n",(long long)st.st_size);

+                        wk_writestr((wk *)web,connid,buf);

+                } else

+                        client->keepalive=0;

+                if(mime!=NULL && strlen(mime)<(sizeof(buf)-sizeof(strcontenttype)-3))

+                        sprintf(buf,"%s%s\r\n",strcontenttype,mime);

+                else

+                        sprintf(buf,"%s%s\r\n",strcontenttype,"application/octet-stream");

                 wk_writestr((wk *)web,connid,buf);

-        } else

-                client->keepalive=0;

-        if(mime!=NULL && strlen(mime)<(sizeof(buf)-sizeof(strcontenttype)-3))

-                sprintf(buf,"%s%s\r\n",strcontenttype,mime);

-        else

-                sprintf(buf,"%s%s\r\n",strcontenttype,"application/octet-stream");

-        wk_writestr((wk *)web,connid,buf);

+        } else {

+                wk_writestr((wk *)web,connid,"Content-Length: 0\r\n");

+        }

         if(client->keepalive)

                 wk_writestr((wk *)web,connid,"Connection: keep-alive\r\n");

         wk_writestr((wk *)web,connid,"\r\n");

@@ -1051,6 +1100,7 @@ wk_clientacquire(_wk *web)

         client->fdtoserve=-1;

         client->headerbufid=-1;

         client->cookiebufid=-1;

+        client->etag[0]='\0';

         return(client);

 }

@@ -1225,6 +1275,9 @@ wk_clientservicereadheader(_wk *web, wk_client *client)

                 client->uriready=1;

                 client->continuationactive=0;

                 client->status=wkc_header;

+                if(client->cookiebufid!=-1)

+                        wk_sbufrelease((wk *)web,client->cookiebufid),client->cookiebufid=-1;

+                client->etag[0]='\0';

         }

         return(0);

 }

@@ -1431,4 +1484,21 @@ wk_postfree(_wk *web, wk_client *client)

         return(0);

 }

+static int

+wk_etagnotmodified(_wk *web, wk_client *client)

+{

+        char *h;

+        int len;

+        int etaglen;

+        if(client->etag[0]=='\0')

+                return(-1);

+        if((h=wk_uri_getheader(&(client->uri),"If-None-Match",NULL))==NULL)

+                return(-1);

+        etaglen=strlen(client->etag);

+        if((len=strlen(h))<2 || h[0]!='\"' || h[len-1]!='\"')

+                return(-1);

+        if((len-2)!=etaglen || memcmp(h+1,client->etag,etaglen)!=0)

+                return(-1);

+        return(0);

+}

@@ -52,6 +52,7 @@ wk_uri *wk_geturi(wk *web, int connid); /* for use in callback_event() when wke_

 int wk_service(wk *web); /* To be called after sselelect_wait() but before sselect_getXXX() */

 int wk_serve_cookieadd(wk *web, int connid, char *cookiename, char *value, char *domain, int maxage, char *attributes);

+int wk_serve_etagset(wk *web, int connid, char *etag);

 int wk_serve_buffer_as_file(wk *web, int connid, void *data, int datalen, const char *mime);

 int wk_serve_file(wk *web, int connid, char *filename, const char *mime);

 int wk_serve_error(wk *web, int connid, wk_error wkerror);