MINOR: httpclient: support payload within a buffer

httpclient_req_gen() takes a payload argument which can be use to put a
payload in the request. This payload can only fit a request buffer.

This payload can also be specified by the "body" named parameter within
the lua. httpclient.

It is also used within the CLI httpclient when specified as a CLI
payload with "<<".
diff --git a/include/haproxy/http_client.h b/include/haproxy/http_client.h
index 097997e..13673e8 100644
--- a/include/haproxy/http_client.h
+++ b/include/haproxy/http_client.h
@@ -9,7 +9,7 @@
 
 struct appctx *httpclient_start(struct httpclient *hc);
 int httpclient_res_xfer(struct httpclient *hc, struct buffer *dst);
-int httpclient_req_gen(struct httpclient *hc, const struct ist url, enum http_meth_t meth, const struct http_hdr *hdrs);
+int httpclient_req_gen(struct httpclient *hc, const struct ist url, enum http_meth_t meth, const struct http_hdr *hdrs, const struct ist payload);
 
 
 /* Return the amount of data available in the httpclient response buffer */
diff --git a/reg-tests/lua/lua_httpclient.lua b/reg-tests/lua/lua_httpclient.lua
index 9ea8e33..5ded14f 100644
--- a/reg-tests/lua/lua_httpclient.lua
+++ b/reg-tests/lua/lua_httpclient.lua
@@ -21,7 +21,7 @@
 	core.Debug('CRON port:' .. vtc_port)
 
 	local httpclient = core.httpclient()
-	local response = httpclient:get{url="http://127.0.0.1:" .. vtc_port}
+	local response = httpclient:get{url="http://127.0.0.1:" .. vtc_port, body="foobar-is-the-new-toto"}
 
 	core.Info("Received: " .. response.body)
 end
diff --git a/src/hlua.c b/src/hlua.c
index ac61a31..a7ed113 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -7164,6 +7164,7 @@
 	struct http_hdr *hdrs_i = NULL;
 	struct hlua *hlua;
 	const char *url_str = NULL;
+	const char *body_str = NULL;
 	int ret;
 
 	hlua = hlua_gethlua(L);
@@ -7187,6 +7188,12 @@
 	}
 	lua_pop(L, 1);
 
+	ret = lua_getfield(L, -1, "body");
+	if (ret == LUA_TSTRING) {
+		body_str = lua_tostring(L, -1);
+	}
+	lua_pop(L, 1);
+
 	if (!url_str) {
 		WILL_LJMP(luaL_error(L, "'get' need a 'url' argument"));
 		return 0;
@@ -7204,7 +7211,7 @@
 	hlua_hc->hc->ops.res_end = hlua_httpclient_res_cb;
 
 
-	httpclient_req_gen(hlua_hc->hc, hlua_hc->hc->req.url, HTTP_METH_GET, hdrs);
+	httpclient_req_gen(hlua_hc->hc, hlua_hc->hc->req.url, HTTP_METH_GET, hdrs, ist(body_str));
 	httpclient_start(hlua_hc->hc);
 
 	/* free the temporary headers array */
diff --git a/src/http_client.c b/src/http_client.c
index f298fe1..4d1ae05 100644
--- a/src/http_client.c
+++ b/src/http_client.c
@@ -116,6 +116,7 @@
 	enum http_meth_t meth;
 	char *meth_str;
 	struct ist uri;
+	struct ist body = IST_NULL;
 
 	if (!cli_has_level(appctx, ACCESS_LVL_ADMIN))
 		return 1;
@@ -128,6 +129,9 @@
 	meth_str = args[1];
 	uri = ist(args[2]);
 
+	if (payload)
+		body = ist(payload);
+
 	meth = find_http_meth(meth_str, strlen(meth_str));
 
 	hc = httpclient_new(appctx, meth, uri);
@@ -144,7 +148,7 @@
 	appctx->ctx.cli.p0 = hc; /* store the httpclient ptr in the applet */
 	appctx->ctx.cli.i0 = 0;
 
-	if (httpclient_req_gen(hc, hc->req.url, hc->req.meth, default_httpclient_hdrs) != ERR_NONE)
+	if (httpclient_req_gen(hc, hc->req.url, hc->req.meth, default_httpclient_hdrs, body) != ERR_NONE)
 		goto err;
 
 
@@ -253,13 +257,13 @@
  * If the buffer was filled correctly the function returns 0, if not it returns
  * an error_code but there is no guarantee that the buffer wasn't modified.
  */
-int httpclient_req_gen(struct httpclient *hc, const struct ist url, enum http_meth_t meth, const struct http_hdr *hdrs)
+int httpclient_req_gen(struct httpclient *hc, const struct ist url, enum http_meth_t meth, const struct http_hdr *hdrs, const struct ist payload)
 {
 	struct htx_sl *sl;
 	struct htx *htx;
 	int err_code = 0;
 	struct ist meth_ist, vsn;
-	unsigned int flags = HTX_SL_F_VER_11 | HTX_SL_F_BODYLESS | HTX_SL_F_XFER_LEN | HTX_SL_F_NORMALIZED_URI | HTX_SL_F_HAS_SCHM;
+	unsigned int flags = HTX_SL_F_VER_11 | HTX_SL_F_NORMALIZED_URI | HTX_SL_F_HAS_SCHM;
 
 	if (meth >= HTTP_METH_OTHER)
 		goto error;
@@ -292,6 +296,13 @@
 			goto error;
 	}
 
+	if (isttest(payload)) {
+		/* add the payload if it can feat in the buffer, no need to set
+		 * the Content-Length, the data will be sent chunked */
+		if (!htx_add_data_atonce(htx, payload))
+			goto error;
+	}
+
 	htx->flags |= HTX_FL_EOM;
 
 	htx_to_buf(htx, &hc->req.buf);