Do If-Modified-Since caching.

diff --git a/statserve.c b/statserve.c
index 9bee73b..1801b95 100644 (file)
--- a/statserve.c
+++ b/statserve.c
@@ -23,6 +23,18 @@ static struct source *parsesource(char *arg)
     }
 }
 
+static int cached(struct hthead *req, struct fileinfo f)
+{
+    char *hdr;
+    time_t cdate;
+    
+    if((hdr = getheader(req, "If-Modified-Since")) != NULL) {
+       cdate = parsehttpdate(hdr);
+       return((cdate > 0) && !(cdate < f.mtime));
+    }
+    return(0);
+}
+
 static void serve(struct muth *muth, va_list args)
 {
     vavar(struct hthead *, req);
@@ -42,12 +54,18 @@ static void serve(struct muth *muth, va_list args)
        goto out;
     }
     out = mtstdopen(fd, 1, 60, "r+");
-    fprintf(out, "HTTP/1.1 200 OK\n");
-    fprintf(out, "Content-Type: %s\n", f.ctype);
-    fprintf(out, "Content-Length: %zi\n", f.sz);
-    fprintf(out, "Last-Modified: %s\n", fmthttpdate(f.mtime));
-    fprintf(out, "\n");
-    fwrite(f.data, 1, f.sz, out);
+    if(cached(req, f)) {
+       fprintf(out, "HTTP/1.1 304 Not Modified\n");
+       fprintf(out, "Content-Length: 0\n");
+       fprintf(out, "\n");
+    } else {
+       fprintf(out, "HTTP/1.1 200 OK\n");
+       fprintf(out, "Content-Type: %s\n", f.ctype);
+       fprintf(out, "Content-Length: %zi\n", f.sz);
+       fprintf(out, "Last-Modified: %s\n", fmthttpdate(f.mtime));
+       fprintf(out, "\n");
+       fwrite(f.data, 1, f.sz, out);
+    }
     free(f.data);
     
 out: