feat: HTTP/1.1 persistent connections (keep-alive)

include/httpcgi.h

@@ -126,8 +126,9 @@ struct httpc {
     UCHAR       ssilevel;           /* 51 SSI processing level          */
 #define SSI_LEVEL_MAX   10          /* ... max SSI processing level     */
     UCHAR       content_length_set; /* 52 Content-Length was sent        */
-    UCHAR       unused2;            /* 53 available                     */
-    unsigned    unused3;            /* 54 available                     */
+    UCHAR       keepalive;          /* 53 keep-alive active             */
+    unsigned short request_count;   /* 54 requests on this connection   */
+    unsigned short unused3;         /* 56 available                     */
 
 #define CBUFSIZE (0x1000-0x0058)    /* ... 4096-88 = 4008               */
     UCHAR       buf[CBUFSIZE];      /* 58 data buffer                   */

include/httpd.h

@@ -145,7 +145,10 @@ struct httpd {
     UCHAR       listen_queue;       /* 120 listen backlog           */
     UCHAR       unused_121[3];      /* 121 alignment padding        */
     char        codepage[16];       /* 124 codepage name            */
-};                                  /* 134                          */
+    UCHAR       cfg_keepalive_timeout; /* 134 keepalive idle secs   */
+    UCHAR       cfg_keepalive_max;  /* 135 max reqs per connection  */
+    UCHAR       unused_136[2];      /* 136 alignment padding        */
+};                                  /* 138                          */
 
 /* HTTP variables */
 struct httpv {
@@ -210,8 +213,9 @@ struct httpc {
     UCHAR		ssilevel;			/* 51 SSI processing level		*/
 #define SSI_LEVEL_MAX	10			/* ... max SSI processing levele*/
 	UCHAR		content_length_set;	/* 52 Content-Length was sent	*/
-	UCHAR		unused2;			/* 53 available					*/
-	unsigned	unused3;			/* 54 available					*/
+	UCHAR		keepalive;			/* 53 keep-alive active			*/
+	unsigned short request_count;	/* 54 requests on this conn		*/
+	unsigned short unused3;			/* 56 available					*/
 
 #define CBUFSIZE (0x1000-0x0058)    /* ... 4096-88 = 4008           */
     UCHAR       buf[CBUFSIZE];      /* 50 data buffer               */

samplib/httpprm0

@@ -17,6 +17,10 @@
 # MAXTASK=9
 # CLIENT_TIMEOUT=10
 #
+# --- Keep-Alive ---
+# KEEPALIVE_TIMEOUT=5
+# KEEPALIVE_MAX=100
+#
 # --- Security ---
 # LOGIN=NONE
 #

src/httpgets.c

@@ -11,8 +11,12 @@ int http_gets(HTTPC *httpc, UCHAR *buf, unsigned max)
     unsigned    seconds;
     unsigned    ecb;
 
-    seconds = httpd->cfg_client_timeout;
-    if (seconds == 0) seconds = 10;
+    if (httpc->request_count > 0 && httpd->cfg_keepalive_timeout) {
+        seconds = httpd->cfg_keepalive_timeout;
+    } else {
+        seconds = httpd->cfg_client_timeout;
+        if (seconds == 0) seconds = 10;
+    }
     time64(&now);
     __64_add_u32(&now, seconds, &timeout);
 

src/httpin.c

@@ -74,6 +74,8 @@ int http_in(HTTPC *httpc)
     /* HTTP/1.1 requires a Host header */
     {
         UCHAR *ver = http_get_env(httpc, "REQUEST_VERSION");
+        UCHAR *conn = http_get_env(httpc, "HTTP_CONNECTION");
+
         if (ver && http_cmp(ver, "HTTP/1.1") == 0) {
             UCHAR *host = http_get_env(httpc, "HTTP_HOST");
             if (!host || !host[0]) {
@@ -83,7 +85,20 @@ int http_in(HTTPC *httpc)
                 httpc->state = CSTATE_DONE;
                 goto quit;
             }
+            /* HTTP/1.1: default keep-alive */
+            httpc->keepalive = 1;
+            if (conn && http_cmp(conn, "close") == 0)
+                httpc->keepalive = 0;
+        } else {
+            /* HTTP/1.0: default close */
+            httpc->keepalive = 0;
+            if (conn && http_cmp(conn, "keep-alive") == 0)
+                httpc->keepalive = 1;
         }
+
+        /* enforce max requests per connection */
+        if (httpc->request_count >= httpc->httpd->cfg_keepalive_max)
+            httpc->keepalive = 0;
     }
 
     /* next step will parse and do any additional processing */
@@ -92,10 +107,13 @@ int http_in(HTTPC *httpc)
     goto quit;
 
 failed:
-    // wtof("%s: failed", __func__);
-
-    /* most likely a bad request, reset the connection */
-    httpc->state = CSTATE_RESET;
+    if (httpc->request_count > 0) {
+        /* keep-alive: idle timeout or client disconnect — just close */
+        httpc->state = CSTATE_CLOSE;
+    } else {
+        /* first request: bad request, reset the connection */
+        httpc->state = CSTATE_RESET;
+    }
 
 quit:
     // wtof("%s: exit rc=%d", __func__, rc);

src/httpprm.c

@@ -87,6 +87,8 @@ http_config(HTTPD *httpd, const char *member)
     wtof("HTTPD033I MINTASK=%d MAXTASK=%d CLIENT_TIMEOUT=%d",
          httpd->cfg_mintask, httpd->cfg_maxtask,
          httpd->cfg_client_timeout);
+    wtof("HTTPD034I KEEPALIVE_TIMEOUT=%d KEEPALIVE_MAX=%d",
+         httpd->cfg_keepalive_timeout, httpd->cfg_keepalive_max);
 
     return 0;
 }
@@ -120,6 +122,8 @@ set_defaults(HTTPD *httpd)
     httpd->docroot[0]       = '\0';
     httpd->codepage[0]      = '\0';
     httpd->dbg_enabled      = 0;
+    httpd->cfg_keepalive_timeout = 5;
+    httpd->cfg_keepalive_max     = 100;
 }
 
 /* ====================================================================
@@ -357,6 +361,18 @@ parse_keyvalue(HTTPD *httpd, const char *key, const char *value)
     else if (strcmp(key, "CLIENT_STATS_DATASET") == 0) {
         if (*value) httpd->st_dataset = strdup(value);
     }
+    else if (strcmp(key, "KEEPALIVE_TIMEOUT") == 0) {
+        i = atoi(value);
+        if (i < 1) i = 1;
+        if (i > 255) i = 255;
+        httpd->cfg_keepalive_timeout = (UCHAR)i;
+    }
+    else if (strcmp(key, "KEEPALIVE_MAX") == 0) {
+        i = atoi(value);
+        if (i < 1) i = 1;
+        if (i > 255) i = 255;
+        httpd->cfg_keepalive_max = (UCHAR)i;
+    }
     else if (strcmp(key, "CGI_CONTEXT_POINTERS") == 0) {
         i = atoi(value);
         if (i >= HTTPD_CGICTX_MIN) {

src/httprese.c

@@ -33,20 +33,26 @@ httprese(HTTPC *httpc)
     httpc->substate = 0;
     httpc->chunked = 0;
     httpc->content_length_set = 0;
-    httpc->start = 0.0;
-    httpc->end = 0.0;
     memset(httpc->buf, 0, CBUFSIZE);
 
     /* clear ACEE on UFS session between requests */
     if (httpc->ufs) {
         ufs_set_acee(httpc->ufs, NULL);
     }
 
-    /* if this is was HTTP1.1 or higher client then we
-    ** *could* transition to CSTATE_IN.  We'll leave that
-    ** for another time.
-    */
-    httpc->state = CSTATE_CLOSE;
+    if (httpc->keepalive) {
+        /* keep connection open for next request */
+        httpc->request_count++;
+        httpc->keepalive = 0;
+        httpc->start = 0.0;
+        httpc->end = 0.0;
+        httpsecs(&httpc->start);
+        httpc->state = CSTATE_IN;
+    } else {
+        httpc->start = 0.0;
+        httpc->end = 0.0;
+        httpc->state = CSTATE_CLOSE;
+    }
 
     http_exit("httprese(), rc=%d\n", rc);
     return rc;

src/httpresp.c

@@ -76,8 +76,11 @@ httpresp(HTTPC *httpc, int resp)
 		if (rc) goto quit;
 	}
 
-    /* HTTP/1.1: always close for now (keep-alive planned) */
-    rc = http_printf(httpc, "Connection: close\r\n");
+    if (httpc->keepalive) {
+        rc = http_printf(httpc, "Connection: keep-alive\r\n");
+    } else {
+        rc = http_printf(httpc, "Connection: close\r\n");
+    }
     if (rc) goto quit;
 
 quit: