minimal: dynamic http server

lib/header.c

@@ -79,6 +79,25 @@ int lws_finalize_http_header(struct lws *wsi, unsigned char **p,
 	return 0;
 }
 
+int
+lws_finalize_write_http_header(struct lws *wsi, unsigned char *start,
+			       unsigned char **pp, unsigned char *end)
+{
+	unsigned char *p;
+	int len;
+
+	if (lws_finalize_http_header(wsi, pp, end))
+		return 1;
+
+	p = *pp;
+	len = lws_ptr_diff(p, start);
+
+	if (lws_write(wsi, start, len, LWS_WRITE_HTTP_HEADERS) != len)
+		return 1;
+
+	return 0;
+}
+
 int
 lws_add_http_header_by_token(struct lws *wsi, enum lws_token_indexes token,
 			     const unsigned char *value, int length,
@@ -117,6 +136,23 @@ int lws_add_http_header_content_length(struct lws *wsi,
 	return 0;
 }
 
+int
+lws_add_http_common_headers(struct lws *wsi, unsigned int code,
+			    const char *content_type, lws_filepos_t content_len,
+			    unsigned char **p, unsigned char *end)
+{
+	if (lws_add_http_header_status(wsi, code, p, end))
+		return 1;
+	if (lws_add_http_header_by_token(wsi, WSI_TOKEN_HTTP_CONTENT_TYPE,
+		    			(unsigned char *)content_type,
+		    			strlen(content_type), p, end))
+		return 1;
+	if (lws_add_http_header_content_length(wsi, content_len, p, end))
+		return 1;
+
+	return 0;
+}
+
 STORE_IN_ROM static const char * const err400[] = {
 	"Bad Request",
 	"Unauthorized",

lib/libwebsockets.h

@@ -4131,6 +4131,49 @@ lws_add_http_header_content_length(struct lws *wsi,
 LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT
 lws_finalize_http_header(struct lws *wsi, unsigned char **p,
 			 unsigned char *end);
+
+/**
+ * lws_finalize_write_http_header() - Helper finializing and writing http headers
+ *
+ * \param wsi: the connection to check
+ * \param start: pointer to the start of headers in the buffer, eg &buf[LWS_PRE]
+ * \param p: pointer to current position in buffer pointer
+ * \param end: pointer to end of buffer
+ *
+ * Terminates the headers correctly accoring to the protocol in use (h1 / h2)
+ * and writes the headers.  Returns nonzero for error.
+ */
+LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT
+lws_finalize_write_http_header(struct lws *wsi, unsigned char *start,
+			       unsigned char **p, unsigned char *end);
+
+/**
+ * lws_add_http_common_headers() - Helper preparing common http headers
+ *
+ * \param wsi: the connection to check
+ * \param code: an HTTP code like 200, 404 etc (see enum http_status)
+ * \param content_type: the content type, like "text/html"
+ * \param content_len: the content length, in bytes
+ * \param p: pointer to current position in buffer pointer
+ * \param end: pointer to end of buffer
+ *
+ * Adds the initial response code, so should be called first.
+ *
+ * Code may additionally take OR'd flags:
+ *
+ *    LWSAHH_FLAG_NO_SERVER_NAME:  don't apply server name header this time
+ *
+ * This helper just calls public apis to simplify adding headers that are
+ * commonly needed.  If it doesn't fit your case, or you want to add additional
+ * headers just call the public apis directly yourself for what you want.
+ *
+ * It does not call lws_finalize_http_header(), to allow you to add further
+ * headers after calling this.  You will need to call that yourself at the end.
+ */
+LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT
+lws_add_http_common_headers(struct lws *wsi, unsigned int code,
+			    const char *content_type, lws_filepos_t content_len,
+			    unsigned char **p, unsigned char *end);
 ///@}
 
 /** \defgroup form-parsing  Form Parsing

lib/server/server.c

@@ -1474,7 +1474,9 @@ lws_http_action(struct lws *wsi)
 	wsi->cache_revalidate = hit->cache_revalidate;
 	wsi->cache_intermediaries = hit->cache_intermediaries;
 
-	n = lws_http_serve(wsi, s, hit->origin, hit);
+	n = 1;
+	if (hit->origin_protocol == LWSMPRO_FILE)
+		n = lws_http_serve(wsi, s, hit->origin, hit);
 	if (n) {
 		/*
 		 * lws_return_http_status(wsi, HTTP_STATUS_NOT_FOUND, NULL);
@@ -2795,7 +2797,7 @@ lws_serve_http_file(struct lws *wsi, const char *file, const char *content_type,
 		wsi->http.fop_fd = fops->LWS_FOP_OPEN(wsi->context->fops,
 							file, vpath, &fflags);
 		if (!wsi->http.fop_fd) {
-			lwsl_err("Unable to open '%s': errno %d\n", file, errno);
+			lwsl_err("Unable to open: '%s': errno %d\n", file, errno);
 
 			return -1;
 		}

minimal-examples/http-server/README.md

@@ -4,3 +4,4 @@ minimal-http-server|Serves a directory over http/1 or http/2, custom 404 handler
 minimal-http-server-libuv|Same as minimal-http-server but libuv event loop
 minimal-http-server-multivhost|Same as minimal-http-server but three different vhosts
 minimal-http-server-smp|Multiple service threads
+minimal-http-server-dynamic|Serves both static and dynamically generated http content

minimal-examples/http-server/minimal-http-server-dynamic/CMakeLists.txt

@@ -0,0 +1,76 @@
+cmake_minimum_required(VERSION 2.8)
+include(CheckSymbolExists)
+
+set(SAMP lws-minimal-http-server-dynamic)
+set(SRCS minimal-http-server-dynamic.c)
+
+# If we are being built as part of lws, confirm current build config supports
+# reqconfig, else skip building ourselves.
+#
+# If we are being built externally, confirm installed lws was configured to
+# support reqconfig, else error out with a helpful message about the problem.
+#
+MACRO(require_lws_config reqconfig _val result)
+
+	if (DEFINED ${reqconfig})
+	if (${reqconfig})
+		set (rq 1)
+	else()
+		set (rq 0)
+	endif()
+	else()
+		set(rq 0)
+	endif()
+
+	if (${_val} EQUAL ${rq})
+		set(SAME 1)
+	else()
+		set(SAME 0)
+	endif()
+
+	if (LWS_WITH_MINIMAL_EXAMPLES AND NOT ${SAME})
+		if (${_val})
+			message("${SAMP}: skipping as lws being built without ${reqconfig}")
+		else()
+			message("${SAMP}: skipping as lws built with ${reqconfig}")
+		endif()
+		set(${result} 0)
+	else()
+		if (LWS_WITH_MINIMAL_EXAMPLES)
+			set(MET ${SAME})
+		else()
+			CHECK_SYMBOL_EXISTS(${reqconfig} libwebsockets.h HAS)
+			if (NOT DEFINED HAS)
+				set(HAS 0)
+			endif()
+			if ((HAS AND ${_val}) OR (NOT HAS AND NOT ${_val}))
+				set(MET 1)
+			else()
+				set(MET 0)
+			endif()
+	
+		endif()
+		if (NOT MET)
+			if (${_val})
+				message(FATAL_ERROR "This project requires lws must have been configured with ${reqconfig}")
+			else()
+				message(FATAL_ERROR "Lws configuration of ${reqconfig} is incompatible with this project")
+			endif()
+		endif()
+	
+	endif()
+ENDMACRO()
+
+set(requirements 1)
+require_lws_config(LWS_WITHOUT_SERVER 0 requirements)
+
+if (requirements)
+	add_executable(${SAMP} ${SRCS})
+
+	if (websockets_shared)
+		target_link_libraries(${SAMP} websockets_shared)
+		add_dependencies(${SAMP} websockets_shared)
+	else()
+		target_link_libraries(${SAMP} websockets)
+	endif()
+endif()

minimal-examples/http-server/minimal-http-server-dynamic/README.md

@@ -0,0 +1,20 @@
+# lws minimal http server dynamic content
+
+## build
+
+```
+ $ cmake . && make
+```
+
+## usage
+
+```
+ $ ./lws-minimal-http-server-dynamic
+[2018/03/20 10:24:24:7099] USER: LWS minimal http server dynamic | visit http://localhost:7681
+[2018/03/20 10:24:24:7099] NOTICE: Creating Vhost 'default' port 7681, 1 protocols, IPv6 off
+```
+
+Visit http://localhost:7681, which is all static content.
+
+Click on the link to /dyn/anything, this opens a new tab with dynamicly-produced content.
+

minimal-examples/http-server/minimal-http-server-dynamic/minimal-http-server-dynamic.c

@@ -0,0 +1,184 @@
+/*
+ * lws-minimal-http-server-dynamic
+ *
+ * Copyright (C) 2018 Andy Green <andy@warmcat.com>
+ *
+ * This file is made available under the Creative Commons CC0 1.0
+ * Universal Public Domain Dedication.
+ *
+ * This demonstrates a minimal http server that can produce dynamic http
+ * content as well as static content.
+ *
+ * To keep it simple, it serves the static stuff from the subdirectory
+ * "./mount-origin" of the directory it was started in.
+ *
+ * You can change that by changing mount.origin below.
+ */
+
+#include <libwebsockets.h>
+#include <string.h>
+#include <signal.h>
+#include <time.h>
+
+/*
+ * Unlike ws, http is a stateless protocol.  This pss only exists for the
+ * duration of a single http transaction.  With http/1.1 keep-alive and http/2,
+ * that is unrelated to (shorter than) the lifetime of the network connection.
+ */
+struct pss {
+	char str[128];
+	int len;
+};
+
+static int interrupted;
+
+static int
+callback_dynamic_http(struct lws *wsi, enum lws_callback_reasons reason,
+			void *user, void *in, size_t len)
+{
+	struct pss *pss = (struct pss *)user;
+	uint8_t buf[LWS_PRE + 256], *start = &buf[LWS_PRE], *p = start,
+		*end = &buf[sizeof(buf) - 1];
+	time_t t;
+
+	switch (reason) {
+	case LWS_CALLBACK_HTTP:
+
+		/* in contains the url part after our mountpoint /dyn, if any */
+
+		t = time(NULL);
+		pss->len = lws_snprintf(pss->str, sizeof(pss->str),
+				"<html>"
+				"<img src=\"/libwebsockets.org-logo.png\">"
+				"<br>Dynamic content for '%s' from mountpoint."
+				"<br>Time: %s"
+				"</html>", (const char *)in, ctime(&t));
+
+		/* prepare and write http headers */
+		if (lws_add_http_common_headers(wsi, HTTP_STATUS_OK,
+						"text/html", pss->len, &p, end))
+			return 1;
+		if (lws_finalize_write_http_header(wsi, start, &p, end))
+			return 1;
+
+		/* write the body separately */
+		lws_callback_on_writable(wsi);
+
+		return 0;
+
+	case LWS_CALLBACK_HTTP_WRITEABLE:
+
+		if (!pss || !pss->len)
+			break;
+
+		/*
+		 * Use LWS_WRITE_HTTP for intermediate writes, on http/2
+		 * lws uses this to understand to end the stream with this
+		 * frame
+		 */
+		if (lws_write(wsi, (uint8_t *)pss->str, pss->len,
+			      LWS_WRITE_HTTP_FINAL) != pss->len)
+			return 1;
+
+		/*
+		 * HTTP/1.0 no keepalive: close network connection
+		 * HTTP/1.1 or HTTP1.0 + KA: wait / process next transaction
+		 * HTTP/2: stream ended, parent connection remains up
+		 */
+		if (lws_http_transaction_completed(wsi))
+			return -1;
+
+		return 0;
+
+	default:
+		break;
+	}
+
+	return lws_callback_http_dummy(wsi, reason, user, in, len);
+}
+
+static struct lws_protocols protocols[] = {
+	{ "http", callback_dynamic_http, sizeof(struct pss), 0 },
+	{ NULL, NULL, 0, 0 } /* terminator */
+};
+
+/* override the default mount for /dyn in the URL space */
+
+static const struct lws_http_mount mount_dyn = {
+	/* .mount_next */		NULL,		/* linked-list "next" */
+	/* .mountpoint */		"/dyn",		/* mountpoint URL */
+	/* .origin */			NULL,	/* protocol */
+	/* .def */			NULL,
+	/* .protocol */			"http",
+	/* .cgienv */			NULL,
+	/* .extra_mimetypes */		NULL,
+	/* .interpret */		NULL,
+	/* .cgi_timeout */		0,
+	/* .cache_max_age */		0,
+	/* .auth_mask */		0,
+	/* .cache_reusable */		0,
+	/* .cache_revalidate */		0,
+	/* .cache_intermediaries */	0,
+	/* .origin_protocol */		LWSMPRO_CALLBACK, /* dynamic */
+	/* .mountpoint_len */		4,		/* char count */
+	/* .basic_auth_login_file */	NULL,
+};
+
+/* default mount serves the URL space from ./mount-origin */
+
+static const struct lws_http_mount mount = {
+	/* .mount_next */	&mount_dyn,		/* linked-list "next" */
+	/* .mountpoint */		"/",		/* mountpoint URL */
+	/* .origin */		"./mount-origin",	/* serve from dir */
+	/* .def */			"index.html",	/* default filename */
+	/* .protocol */			NULL,
+	/* .cgienv */			NULL,
+	/* .extra_mimetypes */		NULL,
+	/* .interpret */		NULL,
+	/* .cgi_timeout */		0,
+	/* .cache_max_age */		0,
+	/* .auth_mask */		0,
+	/* .cache_reusable */		0,
+	/* .cache_revalidate */		0,
+	/* .cache_intermediaries */	0,
+	/* .origin_protocol */		LWSMPRO_FILE,	/* files in a dir */
+	/* .mountpoint_len */		1,		/* char count */
+	/* .basic_auth_login_file */	NULL,
+};
+
+void sigint_handler(int sig)
+{
+	interrupted = 1;
+}
+
+int main(int argc, char **argv)
+{
+	struct lws_context_creation_info info;
+	struct lws_context *context;
+	int n = 0;
+
+	signal(SIGINT, sigint_handler);
+
+	memset(&info, 0, sizeof info); /* otherwise uninitialized garbage */
+	info.port = 7681;
+	info.protocols = protocols;
+	info.mounts = &mount;
+
+	lws_set_log_level(LLL_ERR | LLL_WARN | LLL_NOTICE | LLL_USER
+			/* | LLL_INFO */ /* | LLL_DEBUG */, NULL);
+
+	lwsl_user("LWS minimal http server dynamic | visit http://localhost:7681\n");
+
+	context = lws_create_context(&info);
+	if (!context) {
+		lwsl_err("lws init failed\n");
+		return 1;
+	}
+
+	while (n >= 0 && !interrupted)
+		n = lws_service(context, 1000);
+
+	lws_context_destroy(context);
+
+	return 0;
+}

minimal-examples/http-server/minimal-http-server-dynamic/mount-origin/404.html

@@ -0,0 +1,9 @@
+<meta charset="UTF-8"> 
+<html>
+	<body>
+		<img src="libwebsockets.org-logo.png"><br>
+		<h1>404</h1>
+		Sorry, that file doesn't exist.
+	</body>
+</html>
+

minimal-examples/http-server/minimal-http-server-dynamic/mount-origin/index.html

@@ -0,0 +1,16 @@
+ <meta charset="UTF-8"> 
+<html>
+	<body>
+		<img src="libwebsockets.org-logo.png"><br>
+	
+		Hello from the <b>minimal http server dynamic content example</b>.
+		<p>
+		This is a static page served from ./mount-origin/index.html.
+		<p>
+		Stuff down /dyn in the URL space is generated dynamically<br>
+		by the callback.  For example, click on
+		<a href="/dyn/anything" target=_blank>/dyn/anything</a> to
+		see dynamic content.
+	</body>
+</html>
+