[hackers] [quark] implement http not modified || Hiltjo Posthuma
 
commit 7cd3150df7612db2aa6aab6dacdda57810fd2888
Author: Hiltjo Posthuma <hiltjo_AT_codemadness.org>
Date:   Sat Feb 15 15:36:52 2014 +0100
    implement http not modified
    
    On each request send "last-modified" header with the modification time of
    each file. the client will store this field and send it on the next
    request(s). On the server check the "if-modified-since" field with the
    modified date sent by the client, depending on this send all the data or
    the "304 not modified" http status.
    
    CAVEAT: it is assumed the exact field will be send by the client, no date/time
    conversion is done for simplicity sake, as far as that's possible with http ;)
diff --git a/quark.c b/quark.c
index 565e091..33f5b10 100644
--- a/quark.c
+++ b/quark.c
_AT_@ -38,6 +38,7 @@ typedef struct {
 
 static const char HttpOk[]           = "200 OK";
 static const char HttpMoved[]        = "301 Moved Permanently";
+static const char HttpNotModified[]  = "304 Not Modified";
 static const char HttpUnauthorized[] = "401 Unauthorized";
 static const char HttpNotFound[]     = "404 Not Found";
 static const char texthtml[]         = "text/html";
_AT_@ -67,6 +68,7 @@ static char host[NI_MAXHOST];
 static char reqbuf[MAXBUFLEN+1];
 static char resbuf[MAXBUFLEN+1];
 static char reqhost[256];
+static char reqmod[256];
 static int fd;
 static Request req;
 
_AT_@ -184,6 +186,18 @@ responsecontenttype(const char *mimetype) {
         return writetext(resbuf);
 }
 
+int
+responsemodified(char *mod) {
+    if(snprintf(resbuf, MAXBUFLEN,
+        "Last-Modified: %s
",
+        mod) >= MAXBUFLEN)
+    {
+        logerrmsg("snprintf failed, buffer sizeof exceeded");
+        return -1;
+    }
+    return writetext(resbuf);
+}
+
 void
 responsefiledata(int fd, off_t size) {
         char buf[BUFSIZ];
_AT_@ -200,10 +214,13 @@ void
 responsefile(void) {
         const char *mimetype = "unknown";
         char *p;
-	int i, ffd;
+	char mod[25];
+	int i, ffd, r;
         struct stat st;
+	time_t t;
 
-	if(stat(reqbuf, &st) == -1 || (ffd = open(reqbuf, O_RDONLY)) == -1) {
+	r = stat(reqbuf, &st);
+	if(r == -1 || (ffd = open(reqbuf, O_RDONLY)) == -1) {
                 logerrmsg("%s requests unknown path %s
", host, reqbuf);
                 if(responsehdr(HttpNotFound) != -1
                 && responsecontenttype(texthtml) != -1)
_AT_@ -214,22 +231,33 @@ responsefile(void) {
                         writetext("
<html><body>404 Not Found</body></html>
");
         }
         else {
-		if((p = strrchr(reqbuf, '.'))) {
-			p++;
-			for(i = 0; i < LENGTH(servermimes); i++)
-				if(!strcmp(servermimes[i].extension, p)) {
-					mimetype = servermimes[i].mimetype;
-					break;
-				}
+		t = st.st_mtim.tv_sec;
+		memcpy(mod, asctime(gmtime(&t)), 24);
+		mod[24] = 0;
+		if(!strcmp(reqmod, mod)) {
+			if(responsehdr(HttpNotModified) != -1)
+				;
+			else
+				return;
+		} else {
+			if((p = strrchr(reqbuf, '.'))) {
+				p++;
+				for(i = 0; i < LENGTH(servermimes); i++)
+					if(!strcmp(servermimes[i].extension, p)) {
+						mimetype = servermimes[i].mimetype;
+						break;
+					}
+			}
+			if(responsehdr(HttpOk) != -1
+			&& responsemodified(mod) != -1
+			&& responsecontentlen(st.st_size) != -1
+			&& responsecontenttype(mimetype) != -1)
+				;
+			else
+				return;
+			if(req.type == GET && writetext("
") != -1)
+				responsefiledata(ffd, st.st_size);
                 }
-		if(responsehdr(HttpOk) != -1
-		&& responsecontentlen(st.st_size) != -1
-		&& responsecontenttype(mimetype) != -1)
-			;
-		else
-			return;
-		if(req.type == GET && writetext("
") != -1)
-			responsefiledata(ffd, st.st_size);
                 close(ffd);
         }
 }
_AT_@ -388,12 +416,23 @@ request(void) {
                 for(p = res; *p && *p != ' ' && *p != '	' && *p != '
' && *p != '
'; p++);
                 if(!*p)
                         goto invalid_request;
-		*p = 0;
                 if(p - res > sizeof reqhost)
                         goto invalid_request;
                 memcpy(reqhost, res, p - res);
                 reqhost[p - res] = 0;
         }
+	if((res = strstr(reqbuf, "If-Modified-Since:"))) {
+		for(res = res + 19; *res && (*res == ' ' || *res == '	'); res++);
+		if(!*res)
+			goto invalid_request;
+		for(p = res; *p && *p != '
' && *p != '
'; p++);
+		if(!*p)
+			goto invalid_request;
+		if(p - res > sizeof reqmod)
+			goto invalid_request;
+		memcpy(reqmod, res, p - res);
+		reqmod[p - res] = 0;
+	}
         for(p = reqbuf; *p && *p != '
' && *p != '
'; p++);
         if(*p == '
' || *p == '
') {
                 *p = 0;
Received on Sun Jul 27 2014 - 12:37:29 CEST
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: Sun Jul 27 2014 - 12:48:09 CEST