http: header improvements

Try harder to avoid some allocations, use Host separately and inherit
from the client.

demo/http_client/http_client.c

@@ -52,7 +52,6 @@ main(int argc, char **argv)
 	nng_http_conn   *conn;
 	nng_url         *url;
 	nng_aio         *aio;
-	nng_http_req    *req;
 	nng_http_res    *res;
 	const char      *hdr;
 	int              rv;
@@ -86,7 +85,6 @@ main(int argc, char **argv)
 	// Get the connection, at the 0th output.
 	conn = nng_aio_get_output(aio, 0);
 	res  = nng_http_conn_res(conn);
-	req  = nng_http_conn_req(conn);
 
 	// Request is already set up with URL, and for GET via HTTP/1.1.
 	// The Host: header is already set up too.

docs/ref/api/http.md

@@ -173,6 +173,27 @@ including any disposing of any underlying file descriptors or related resources.
 
 Once this function, no further access to the _conn_ structure may be made.
 
+### Reset Connection State
+
+```c
+void nng_http_reset(nng_http *conn);
+```
+
+The {{i:`nng_http_reset`}} function resets the request and response state of the
+the connection _conn_.
+
+The "Host" parameter will be retained for client connections, but the URI will not.
+
+The intended purpose of this function is to clear the object state before reusing the _conn_ for
+subsequent transactions.
+
+### Request and Response Headers
+
+```c
+int nng_http_request_add_header(nng_http *conn, const char *key, const char *val);
+int nng_http_request_set_header(nng_http *conn, const char *key, const char *val);
+```
+
 ### Direct Read and Write
 
 ```c

docs/ref/xref.md

@@ -253,6 +253,7 @@
 [`nng_http_client_set_tls`]: /api/http.md#client-tls
 [`nng_http_client_get_tls`]: /api/http.md#client-tls
 [`nng_http_close`]: /api/http.md#closing-connections
+[`nng_http_reset`]: /api/http.md#reset-connection-state
 [`nng_http_get_version`]: /api/http.md#http-protocol-versions
 [`nng_http_set_version`]: /api/http.md#http-protocol-versions
 [`nng_http_get_method`]: /api/http.md#http-method

include/nng/http.h

@@ -100,16 +100,6 @@ typedef struct nng_http_req nng_http_req;
 // the scheme, host, or port.
 NNG_DECL const char *nng_http_req_get_uri(const nng_http_req *);
 
-// nng_http_req_set_header sets an HTTP header, replacing any previous value
-// that might have been present.
-NNG_DECL int nng_http_req_set_header(
-    nng_http_req *, const char *, const char *);
-
-// nng_http_req_add_header adds an HTTP header, without disrupting any other
-// with the same name that might have been present.
-NNG_DECL int nng_http_req_add_header(
-    nng_http_req *, const char *, const char *);
-
 // nng_http_req_del_header deletes all occurrences of a named header.
 NNG_DECL int nng_http_req_del_header(nng_http_req *, const char *);
 
@@ -209,7 +199,7 @@ NNG_DECL void nng_http_write(nng_http *, nng_aio *);
 
 // nng_http_write_all is like nng_http_write, but it does not
 // finish until either all the requested data is written, or an error occurs.
-NNG_DECL void nng_http_conn_write_all(nng_http *, nng_aio *);
+NNG_DECL void nng_http_write_all(nng_http *, nng_aio *);
 
 // nng_http_conn_write_req writes the entire request.  It will also write any
 // data that has been attached.
@@ -261,6 +251,9 @@ NNG_DECL void nng_http_set_method(nng_http *, const char *);
 // nng_http_get_method returns the method.
 NNG_DECL const char *nng_http_get_method(nng_http *);
 
+NNG_DECL int nng_http_add_request_header(
+    nng_http *, const char *, const char *);
+
 // nng_http_handler is a handler used on the server side to handle HTTP
 // requests coming into a specific URL.
 //

src/supplemental/http/http_api.h

@@ -392,6 +392,13 @@ extern int nni_http_conn_set_redirect(
     nng_http *conn, uint16_t status, const char *reason, const char *dest);
 
 extern void nni_http_conn_set_response_content_type(
-    nng_http_conn *conn, const char *ctype);
+    nng_http *conn, const char *ctype);
+
+extern void nni_http_conn_set_host(nng_http *conn, const char *);
+extern void nni_http_conn_reset(nng_http *conn);
+extern int  nni_http_add_request_header(
+     nng_http *conn, const char *key, const char *val);
+extern int nni_http_set_request_header(
+    nng_http *conn, const char *key, const char *val);
 
 #endif // NNG_SUPPLEMENTAL_HTTP_HTTP_API_H

src/supplemental/http/http_client.c

@@ -10,12 +10,14 @@
 //
 
 #include <stdbool.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include "core/nng_impl.h"
 
 #include "http_api.h"
+#include "http_msg.h"
 
 static nni_mtx http_txn_lk = NNI_MTX_INITIALIZER;
 
@@ -24,6 +26,7 @@ struct nng_http_client {
 	nni_mtx            mtx;
 	bool               closed;
 	nni_aio            aio;
+	char               host[260];
 	nng_stream_dialer *dialer;
 };
 
@@ -71,6 +74,8 @@ http_dial_cb(void *arg)
 	NNI_ASSERT(stream != NULL);
 
 	rv = nni_http_conn_init(&conn, stream);
+
+	// set up the host header
 	http_dial_start(c);
 	nni_mtx_unlock(&c->mtx);
 
@@ -79,7 +84,7 @@ http_dial_cb(void *arg)
 		nni_aio_finish_error(aio, rv);
 		return;
 	}
-
+	nni_http_conn_set_host(conn, c->host);
 	nni_aio_set_output(aio, 0, conn);
 	nni_aio_finish(aio, 0, 0);
 }
@@ -110,7 +115,8 @@ nni_http_client_init(nni_http_client **cp, const nng_url *url)
 	memcpy(&my_url, url, sizeof(my_url));
 	my_url.u_scheme = (char *) scheme;
 
-	if (strlen(url->u_hostname) == 0) {
+	if ((strlen(url->u_hostname) == 0) ||
+	    (strlen(url->u_hostname) > 253)) {
 		// We require a valid hostname.
 		return (NNG_EADDRINVAL);
 	}
@@ -122,6 +128,16 @@ nni_http_client_init(nni_http_client **cp, const nng_url *url)
 	nni_aio_list_init(&c->aios);
 	nni_aio_init(&c->aio, http_dial_cb, c);
 
+	if (nni_url_default_port(url->u_scheme) == url->u_port) {
+		snprintf(c->host, sizeof(c->host), "%s", url->u_hostname);
+	} else if (strchr(url->u_hostname, ':') != NULL) {
+		// IPv6 address, needs [wrapping]
+		snprintf(c->host, sizeof(c->host), "[%s]:%d", url->u_hostname,
+		    url->u_port);
+	} else {
+		snprintf(c->host, sizeof(c->host), "%s:%d", url->u_hostname,
+		    url->u_port);
+	}
 	if ((rv = nng_stream_dialer_alloc_url(&c->dialer, &my_url)) != 0) {
 		nni_http_client_fini(c);
 		return (rv);

src/supplemental/http/http_conn.c

@@ -511,12 +511,22 @@ http_wr_submit(nni_http_conn *conn, nni_aio *aio, enum write_flavor flavor)
 	}
 }
 
+void
+nni_http_conn_reset(nng_http_conn *conn)
+{
+	nni_http_req_reset(&conn->req);
+	nni_http_res_reset(&conn->res);
+	if (strlen(conn->req.host)) {
+		nni_http_conn_set_host(conn, conn->req.host);
+	}
+}
+
 void
 nni_http_read_req(nni_http_conn *conn, nni_aio *aio)
 {
 	// clear the sent flag (used for the server)
 	conn->res_sent = false;
-	nni_http_req_reset(&conn->req);
+	nni_http_conn_reset(conn);
 	nni_mtx_lock(&conn->mtx);
 	http_rd_submit(conn, aio, HTTP_RD_REQ);
 	nni_mtx_unlock(&conn->mtx);
@@ -939,6 +949,51 @@ nni_http_conn_set_redirect(
 	return (http_conn_set_error(conn, status, reason, NULL, redirect));
 }
 
+void
+nni_http_conn_set_host(nng_http_conn *conn, const char *host)
+{
+	if (host != conn->req.host) {
+		snprintf(conn->req.host, sizeof(conn->req.host), "%s", host);
+	}
+	nni_list_node_remove(&conn->req.host_header.node);
+	conn->req.host_header.name         = "Host";
+	conn->req.host_header.value        = conn->req.host;
+	conn->req.host_header.static_name  = true;
+	conn->req.host_header.static_value = true;
+	conn->req.host_header.alloc_header = false;
+	nni_list_prepend(&conn->req.hdrs, &conn->req.host_header);
+}
+
+static bool
+http_set_request_known_header(nng_http *conn, const char *key, const char *val)
+{
+	if (nni_strcasecmp(key, "Host") == 0) {
+		nni_http_conn_set_host(conn, val);
+		return (true);
+	}
+	return (false);
+}
+
+int
+nni_http_add_request_header(nng_http *conn, const char *key, const char *val)
+{
+	if (http_set_request_known_header(conn, key, val)) {
+		return (0);
+	}
+
+	return (nni_http_req_add_header(&conn->req, key, val));
+}
+
+int
+nni_http_set_request_header(nng_http *conn, const char *key, const char *val)
+{
+	if (http_set_request_known_header(conn, key, val)) {
+		return (0);
+	}
+
+	return (nni_http_req_set_header(&conn->req, key, val));
+}
+
 void
 nni_http_conn_set_response_content_type(nng_http *conn, const char *ctype)
 {
@@ -976,8 +1031,7 @@ nni_http_conn_fini(nni_http_conn *conn)
 
 	nni_aio_fini(&conn->wr_aio);
 	nni_aio_fini(&conn->rd_aio);
-	nni_http_req_reset(&conn->req);
-	nni_http_res_reset(&conn->res);
+	nni_http_conn_reset(conn);
 	nni_free(conn->rd_buf, conn->rd_bufsz);
 	nni_mtx_fini(&conn->mtx);
 	NNI_FREE_STRUCT(conn);

src/supplemental/http/http_msg.c

@@ -113,37 +113,41 @@ http_del_header(nni_list *hdrs, const char *key)
 	return (NNG_ENOENT);
 }
 
-static void
-http_del_all_headers(nni_list *hdrs, const char *key)
-{
-	while (http_del_header(hdrs, key) == 0) {
-		continue;
-	}
-}
-
 int
 nni_http_req_del_header(nni_http_req *req, const char *key)
 {
-	return (http_del_header(&req->hdrs, key));
+	int rv = NNG_ENOENT;
+	while (http_del_header(&req->hdrs, key) == 0) {
+		rv = 0;
+	}
+	return (rv);
 }
 
 int
 nni_http_res_del_header(nni_http_res *res, const char *key)
 {
-	return (http_del_header(&res->hdrs, key));
+	int rv = NNG_ENOENT;
+	while (http_del_header(&res->hdrs, key) == 0) {
+		rv = 0;
+	}
+	return (rv);
 }
 
 static int
 http_set_header(nni_list *hdrs, const char *key, const char *val)
 {
 	http_header *h;
+
 	NNI_LIST_FOREACH (hdrs, h) {
 		if (nni_strcasecmp(key, h->name) == 0) {
 			char *news;
 			if ((news = nni_strdup(val)) == NULL) {
 				return (NNG_ENOMEM);
 			}
-			nni_strfree(h->value);
+			if (!h->static_value) {
+				nni_strfree(h->value);
+				h->value = NULL;
+			}
 			h->value = news;
 			return (0);
 		}
@@ -309,7 +313,7 @@ void
 nni_http_req_set_content_length(nni_http_req *req, size_t size)
 {
 	snprintf(req->clen, sizeof(req->clen), "%lu", (unsigned long) size);
-	http_del_all_headers(&req->hdrs, "Content-Length");
+	nni_http_req_del_header(req, "Content-Length");
 	nni_list_node_remove(&req->content_length.node);
 	req->content_length.name         = "Content-Length";
 	req->content_length.value        = req->clen;
@@ -322,7 +326,7 @@ void
 nni_http_res_set_content_length(nni_http_res *res, size_t size)
 {
 	snprintf(res->clen, sizeof(res->clen), "%lu", (unsigned long) size);
-	http_del_all_headers(&res->hdrs, "Content-Length");
+	nni_http_res_del_header(res, "Content-Length");
 	nni_list_node_remove(&res->content_length.node);
 	res->content_length.name         = "Content-Length";
 	res->content_length.value        = res->clen;
@@ -334,7 +338,7 @@ nni_http_res_set_content_length(nni_http_res *res, size_t size)
 void
 nni_http_res_set_content_type(nni_http_res *res, const char *ctype)
 {
-	http_del_all_headers(&res->hdrs, "Content-Type");
+	nni_http_res_del_header(res, "Content-Type");
 	nni_list_node_remove(&res->content_type.node);
 	res->content_type.name           = "Content-Type";
 	res->content_type.value          = (char *) ctype;
@@ -346,7 +350,7 @@ nni_http_res_set_content_type(nni_http_res *res, const char *ctype)
 void
 nni_http_req_set_content_type(nni_http_req *req, const char *ctype)
 {
-	http_del_all_headers(&req->hdrs, "Content-Type");
+	nni_http_req_del_header(req, "Content-Type");
 	nni_list_node_remove(&req->content_type.node);
 	req->content_type.name           = "Content-Type";
 	req->content_type.value          = (char *) ctype;

src/supplemental/http/http_msg.h

@@ -38,14 +38,16 @@ struct nng_http_req {
 	nni_list        hdrs;
 	nni_http_entity data;
 	char            meth[32];
+	char            clen[28];
+	char            host[260]; // 253 per IETF, plus 6 for :port plus null
 	char           *uri;
 	const char     *vers;
 	char           *buf;
 	size_t          bufsz;
 	bool            parsed;
-	char            clen[28];
 	http_header     content_type;
 	http_header     content_length;
+	http_header     host_header;
 };
 
 struct nng_http_res {