ari_websockets.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2013, Digium, Inc.
 *
 * David M. Lee, II <dlee@digium.com>
 *
 * 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 <dlee@digium.com>
 */
 
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);
}