ari_websockets.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2013, Digium, Inc.
 *
 * David M. Lee, II <[email protected]>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

#include "asterisk.h"

#include "asterisk/ari.h"
#include "asterisk/astobj2.h"
#include "asterisk/http_websocket.h"
#include "asterisk/stasis_app.h"
#include "internal.h"

/*! \file
 *
 * \brief WebSocket support for RESTful API's.
 * \author David M. Lee, II <[email protected]>
 */

struct ast_ari_websocket_session {
 struct ast_websocket *ws_session;
 int (*validator)(struct ast_json *);
};

static void websocket_session_dtor(void *obj)
{
 struct ast_ari_websocket_session *session = obj;

 ast_websocket_unref(session->ws_session);
 session->ws_session = NULL;
}

/*!
 * \brief Validator that always succeeds.
 */
static int null_validator(struct ast_json *json)
{
 return 1;
}

struct ast_ari_websocket_session *ast_ari_websocket_session_create(
 struct ast_websocket *ws_session, int (*validator)(struct ast_json *))
{
 RAII_VAR(struct ast_ari_websocket_session *, session, NULL, ao2_cleanup);
 RAII_VAR(struct ast_ari_conf *, config, ast_ari_config_get(), ao2_cleanup);

 if (ws_session == NULL) {
 return NULL;
 }

 if (config == NULL || config->general == NULL) {
 return NULL;
 }

 if (validator == NULL) {
 validator = null_validator;
 }

 if (ast_websocket_set_nonblock(ws_session) != 0) {
 ast_log(LOG_ERROR,
 "ARI web socket failed to set nonblock; closing: %s\n",
 strerror(errno));
 return NULL;
 }

 if (ast_websocket_set_timeout(ws_session, config->general->write_timeout)) {
 ast_log(LOG_WARNING, "Failed to set write timeout %d on ARI web socket\n",
 config->general->write_timeout);
 }

 session = ao2_alloc(sizeof(*session), websocket_session_dtor);
 if (!session) {
 return NULL;
 }

 ao2_ref(ws_session, +1);
 session->ws_session = ws_session;
 session->validator = validator;

 ao2_ref(session, +1);
 return session;
}

struct ast_json *ast_ari_websocket_session_read(
 struct ast_ari_websocket_session *session)
{
 RAII_VAR(struct ast_json *, message, NULL, ast_json_unref);

 if (ast_websocket_fd(session->ws_session) < 0) {
 return NULL;
 }

 while (!message) {
 int res;
 char *payload;
 uint64_t payload_len;
 enum ast_websocket_opcode opcode;
 int fragmented;

 res = ast_wait_for_input(
 ast_websocket_fd(session->ws_session), -1);

 if (res <= 0) {
 ast_log(LOG_WARNING, "WebSocket poll error: %s\n",
 strerror(errno));
 return NULL;
 }

 res = ast_websocket_read(session->ws_session, &payload,
 &payload_len, &opcode, &fragmented);

 if (res != 0) {
 ast_log(LOG_WARNING, "WebSocket read error: %s\n",
 strerror(errno));
 return NULL;
 }

 switch (opcode) {
 case AST_WEBSOCKET_OPCODE_CLOSE:
 ast_debug(1, "WebSocket closed\n");
 return NULL;
 case AST_WEBSOCKET_OPCODE_TEXT:
 message = ast_json_load_buf(payload, payload_len, NULL);
 if (message == NULL) {
 ast_log(LOG_WARNING,
 "WebSocket input failed to parse\n");
 }

 break;
 default:
 /* Ignore all other message types */
 break;
 }
 }

 return ast_json_ref(message);
}

#define VALIDATION_FAILED \
 "{" \
 " \"error\": \"InvalidMessage\"," \
 " \"message\": \"Message validation failed\"" \
 "}"

int ast_ari_websocket_session_write(struct ast_ari_websocket_session *session,
 struct ast_json *message)
{
 RAII_VAR(char *, str, NULL, ast_json_free);

#ifdef AST_DEVMODE
 if (!session->validator(message)) {
 ast_log(LOG_ERROR, "Outgoing message failed validation\n");
 return ast_websocket_write_string(session->ws_session, VALIDATION_FAILED);
 }
#endif

 str = ast_json_dump_string_format(message, ast_ari_json_format());

 if (str == NULL) {
 ast_log(LOG_ERROR, "Failed to encode JSON object\n");
 return -1;
 }

 if (ast_websocket_write_string(session->ws_session, str)) {
 ast_log(LOG_NOTICE, "Problem occurred during websocket write to %s, websocket closed\n",
 ast_sockaddr_stringify(ast_ari_websocket_session_get_remote_addr(session)));
 return -1;
 }
 return 0;
}

struct ast_sockaddr *ast_ari_websocket_session_get_remote_addr(
 struct ast_ari_websocket_session *session)
{
 return ast_websocket_remote_address(session->ws_session);
}

void ari_handle_websocket(struct ast_websocket_server *ws_server,
 struct ast_tcptls_session_instance *ser, const char *uri,
 enum ast_http_method method, struct ast_variable *get_params,
 struct ast_variable *headers)
{
 struct ast_http_uri fake_urih = {
 .data = ws_server,
 };
 ast_websocket_uri_cb(ser, &fake_urih, uri, method, get_params,
 headers);
}

const char *ast_ari_websocket_session_id(
 const struct ast_ari_websocket_session *session)
{
 return ast_websocket_session_id(session->ws_session);
}