1 files changed, 203 insertions, 0 deletions
diff --git a/serve.c b/serve.c
new file mode 100644
index 0000000..dd61da1
--- /dev/null
+++ b/serve.c
@@ -0,0 +1,203 @@
+/**
+ * part of Hydrilla
+ * Serving data queries over HTTP using libmicrohttpd.
+ *
+ * Copyright (C) 2021 Wojtek Kosior
+ * Redistribution terms are gathered in the `copyright' file.
+ *
+ * This file is based on Christian Grothoff's public comain code from
+ * `doc/examples/logging.c' in libmicrohttpd source tree.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <sys/types.h>
+#include <sys/select.h>
+#include <sys/socket.h>
+
+#include <microhttpd.h>
+
+#include "scriptbase.h"
+
+#define PORT 10111
+
+#define ARRLEN(array) (sizeof(array) / sizeof(*array))
+
+static struct MHD_Response *default_response, *error_response,
+	*not_found_response;
+
+static struct {
+	struct MHD_Response **response;
+	const char *const text;
+} static_responses[] = {
+	{&default_response,   "<html><body>Nothing to see here</body></html>"},
+	{&error_response,     "<html><body>Error occured</body></html>"},
+	{&not_found_response, "<html><body>Not found</body></html>"}
+};
+
+static int add_CORS_header(struct MHD_Response *response)
+{
+	return -1 * (MHD_add_response_header(response,
+					     "Access-Control-Allow-Origin",
+					     "*") == MHD_NO);
+}
+
+typedef char *(*request_handler_t)(const char *queried,
+				   struct scriptbase *base);
+
+static struct {
+	const char *path;
+	request_handler_t request_handler;
+} resources[] = {
+		 {"/script",  get_script_json},
+		 {"/bag",     get_bag_json},
+		 {"/pattern", get_pattern_json},
+		 {"/query",   get_page_query_json}
+};
+
+struct request_handling {
+	struct scriptbase *base;
+	request_handler_t handler;
+	char *json_response;
+	int error_number;
+};
+
+static int handle_query_argument(void *cls, enum MHD_ValueKind kind,
+				 const char *key, const char *value)
+{
+	struct request_handling *handling = cls;
+
+	if (strcmp(key, "n")) {
+		fprintf(stderr, "Unknown argument: \"%s\" = \"%s\"\n",
+			key, value);
+		return MHD_YES;
+	}
+
+	errno = 0;
+
+	handling->json_response = handling->handler(value, handling->base);
+
+	handling->error_number = errno;
+
+	return MHD_NO;
+}
+
+static int answer_with(struct MHD_Connection *connection,
+		       request_handler_t handler, struct scriptbase *base)
+{
+	struct request_handling handling = {base, handler, NULL, EINVAL};
+	struct MHD_Response *response;
+	int retval;
+
+	MHD_get_connection_values(connection, MHD_GET_ARGUMENT_KIND,
+				  handle_query_argument, &handling);
+
+	if (!handling.json_response) {
+		if (handling.error_number)
+			goto send_error;
+		goto send_not_found;
+	}
+
+	response = MHD_create_response_from_buffer
+		(strlen(handling.json_response), handling.json_response,
+		 MHD_RESPMEM_MUST_FREE);
+	if (!response || add_CORS_header(response))
+		goto send_error;
+
+	retval = MHD_queue_response(connection, MHD_HTTP_OK, response);
+	MHD_destroy_response(response);
+
+	return retval;
+
+send_not_found:
+	return MHD_queue_response(connection, MHD_HTTP_NOT_FOUND,
+				  not_found_response);
+
+send_error:
+	free(handling.json_response);
+	return MHD_queue_response(connection, MHD_HTTP_INTERNAL_SERVER_ERROR,
+				  error_response);
+}
+
+static int answer(void *data,
+		  struct MHD_Connection *connection,
+		  const char *url,
+		  const char *method,
+		  const char *version,
+		  const char *upload_data,
+		  size_t *upload_data_size,
+		  void **ptr)
+{
+	static int aptr;
+	int i;
+	struct scriptbase *base = data;
+
+	printf("New %s request for %s using version %s\n", method, url, version);
+
+	if (strcmp(method, "GET"))
+		return MHD_NO;
+
+	if (&aptr != *ptr) {
+		/* do never respond on first call */
+		*ptr = &aptr;
+		return MHD_YES;
+	}
+	*ptr = NULL; /* reset when done */
+
+	for (i = 0; i < ARRLEN(resources); i++) {
+		if (strcmp(resources[i].path, url))
+			continue;
+
+		return answer_with(connection, resources[i].request_handler,
+				   base);
+	}
+
+	return MHD_queue_response(connection, MHD_HTTP_OK, default_response);
+}
+
+int getchar(void);
+
+int serve_scriptbase(struct scriptbase *base)
+{
+	int i;
+	struct MHD_Daemon *daemon;
+	int retval = -1;
+
+	if (init_url_lookup_regex())
+	  return -1;
+
+	for (i = 0; i < ARRLEN(static_responses); i++) {
+		*static_responses[i].response = MHD_create_response_from_buffer
+			(strlen(static_responses[i].text),
+			 (char*) static_responses[i].text,
+			 MHD_RESPMEM_PERSISTENT);
+
+		if (!*static_responses[i].response ||
+		    add_CORS_header(*static_responses[i].response))
+			goto free_resources;
+	}
+
+	daemon = MHD_start_daemon(MHD_USE_INTERNAL_POLLING_THREAD, PORT, NULL,
+				  NULL, &answer, (void*) base, MHD_OPTION_END);
+	if (!daemon)
+		goto free_resources;
+
+	getchar();
+	MHD_stop_daemon(daemon);
+
+	retval = 0;
+
+free_resources:
+	for (i = 0; i < ARRLEN(static_responses); i++) {
+		if (*static_responses[i].response)
+			MHD_destroy_response(*static_responses[i].response);
+		*static_responses[i].response = NULL;
+	}
+
+	destroy_url_lookup_regex();
+
+	return retval;
+}