core-legacy/router.c

#include <string.h>

#include <logger.h>
#include <router.h>
#include <macros.h>
#include <endpoint.h>

#include <endpoints/api_v1_schedules.h>
#include <endpoints/api_v1_controllers.h>
#include <endpoints/api_v1_relays.h>
#include <endpoints/api_v1_tags.h>

static endpoint_t endpoints[ROUTER_ENDPOINTS_MAX_COUNT];
static endpoint_t endpoint_not_found;
static int endpoints_registered = 0;
static const char delimiter[2] = "/";

static struct mg_str
get_method_str_for_int(int method_int)
{
    if(method_int == HTTP_METHOD_GET)
    {
        return mg_mk_str("GET");
    }
    if(method_int == HTTP_METHOD_POST)
    {
        return mg_mk_str("POST");
    }
    if(method_int == HTTP_METHOD_PUT)
    {
        return mg_mk_str("PUT");
    }
    if(method_int == HTTP_METHOD_DELETE)
    {
        return mg_mk_str("DELETE");
    }
    if(method_int == HTTP_METHOD_OPTIONS)
    {
        return mg_mk_str("OPTIONS");
    }
    return mg_mk_str("GET");
}

endpoint_t*
router_get_not_found_endpoint()
{
    return &endpoint_not_found;
}

void
router_init()
{
    // add 404 endpoint
    endpoint_not_found.route = NULL;
    endpoint_not_found.func = endpoint_func_not_found;
    endpoint_not_found.method = 0;
    endpoint_not_found.args_count = 0;
    endpoint_not_found.args = NULL;

    router_register_endpoint("/api/v1/schedules/", HTTP_METHOD_GET, api_v1_schedules_GET);
    router_register_endpoint("/api/v1/schedules/", HTTP_METHOD_POST, api_v1_schedules_POST);
    router_register_endpoint("/api/v1/schedules/{str}", HTTP_METHOD_GET, api_v1_schedules_STR_GET);
    router_register_endpoint("/api/v1/schedules/{str}", HTTP_METHOD_PUT, api_v1_schedules_STR_PUT);
    router_register_endpoint("/api/v1/schedules/{str}", HTTP_METHOD_DELETE, api_v1_schedules_STR_DELETE);
    router_register_endpoint("/api/v1/schedules/tag/{str}", HTTP_METHOD_GET, api_v1_schedules_tag_STR_GET);

    router_register_endpoint("/api/v1/controllers/discover/", HTTP_METHOD_POST, api_v1_controllers_discover_POST);
    router_register_endpoint("/api/v1/controllers/", HTTP_METHOD_GET, api_v1_controllers_GET);
    router_register_endpoint("/api/v1/controllers/{str}", HTTP_METHOD_GET, api_v1_controllers_STR_GET);
    router_register_endpoint("/api/v1/controllers/{str}", HTTP_METHOD_PUT, api_v1_controllers_STR_PUT);
    router_register_endpoint("/api/v1/controllers/{str}", HTTP_METHOD_DELETE, api_v1_controllers_STR_DELETE);

    router_register_endpoint("/api/v1/controllers/{str}/relays/", HTTP_METHOD_GET, api_v1_controllers_STR_relays_GET);
    router_register_endpoint("/api/v1/controllers/{str}/relays/{int}", HTTP_METHOD_GET, api_v1_controllers_STR_relays_INT_GET);
    router_register_endpoint("/api/v1/controllers/{str}/relays/{int}", HTTP_METHOD_PUT, api_v1_controllers_STR_relays_INT_PUT);

    router_register_endpoint("/api/v1/relays/", HTTP_METHOD_GET, api_v1_relays_GET);
    router_register_endpoint("/api/v1/relays/tag/{str}", HTTP_METHOD_GET, api_v1_relays_tag_STR_GET);

    router_register_endpoint("/api/v1/tags/", HTTP_METHOD_GET, api_v1_tags_GET);
}

endpoint_t*
router_register_endpoint(const char *route, int method, endpoint_func_f func)
{
    endpoint_t *options_endpoint = NULL;
    if(method != HTTP_METHOD_OPTIONS)
    {
        struct mg_str method_str = get_method_str_for_int(HTTP_METHOD_OPTIONS);
        options_endpoint = router_find_endpoint(route, strlen(route), &method_str);
        if(options_endpoint == NULL)
        {
            options_endpoint = router_register_endpoint(route, HTTP_METHOD_OPTIONS, NULL);
        }
        else
        {
            for(int i = 0; i < options_endpoint->args_count; ++i)
            {
                if(options_endpoint->args[i].type == ENDPOINT_ARG_TYPE_STR)
                {
                    free((char*)options_endpoint->args[i].value.v_str);
                }
            }
        }
    }

    if(endpoints_registered >= ROUTER_ENDPOINTS_MAX_COUNT)
    {
        LOG_ERROR("can't register more than %d endpoints\n", ROUTER_ENDPOINTS_MAX_COUNT);
        return NULL;
    }

    endpoint_t *endpoint = &endpoints[endpoints_registered];

    endpoint->full_route = route;
    endpoint->trailing_slash = 0; // unused because trailing slashes are optional. TODO make option
    if(route[strlen(route)] == delimiter[0])
    {
        endpoint->trailing_slash = 1;
    }

    int route_parts_count = 1;
    size_t route_len = strlen(route);

    for(size_t i = 0; i < route_len; ++i)
    {
        if(route[i] == delimiter[0] || route[i] == '\0')
        {
            ++route_parts_count;
        }
    }

    // +1 for NULL terminator
    endpoint->route = malloc(sizeof(char*) * (route_parts_count + 1));
    endpoint->route_keeper = malloc(sizeof(char) * (route_len + 1));
    strncpy(endpoint->route_keeper, route, route_len);
    endpoint->route_keeper[route_len] = '\0';

    int route_part = 0;
    int route_args_count = 0;

    char *route_token = strtok(endpoint->route_keeper, delimiter);
    while(route_token)
    {
        if(strcmp(route_token, "{int}") == 0)
        {
            ++route_args_count;
        }
        if(strcmp(route_token, "{str}") == 0)
        {
            ++route_args_count;
        }
        endpoint->route[route_part] = route_token;
        ++route_part;
        route_token = strtok(NULL, delimiter);
    }
    endpoint->route[route_part] = NULL;

    endpoint->args_count = route_args_count;
    endpoint->args = NULL;
    if(route_args_count)
    {
        endpoint->args = malloc(sizeof(endpoint_args_t) * route_args_count);
    }

    endpoint->func = func;
    endpoint->method = method;
    endpoint->options = 0;

    if(options_endpoint)
    {
        options_endpoint->options |= method;
    }

    ++endpoints_registered;
    return endpoint;
}

static int
get_method_int_for_str(struct mg_str *method_str)
{
    if(strncmp(method_str->p, "GET", method_str->len) == 0)
    {
        return HTTP_METHOD_GET;
    }
    if(strncmp(method_str->p, "POST", method_str->len) == 0)
    {
        return HTTP_METHOD_POST;
    }
    if(strncmp(method_str->p, "PUT", method_str->len) == 0)
    {
        return HTTP_METHOD_PUT;
    }
    if(strncmp(method_str->p, "DELETE", method_str->len) == 0)
    {
        return HTTP_METHOD_DELETE;
    }
    if(strncmp(method_str->p, "OPTIONS", method_str->len) == 0)
    {
        return HTTP_METHOD_OPTIONS;
    }
    return HTTP_METHOD_GET;
}

endpoint_t*
router_find_endpoint(const char *uri_str, size_t uri_len, struct mg_str *method_str)
{
    char *uri = malloc(sizeof(char) * (uri_len + 1));
    strncpy(uri, uri_str, uri_len);
    uri[uri_len] = '\0';

    int method = get_method_int_for_str(method_str);

    for(int i = 0; i < endpoints_registered; ++i)
    {
        if(endpoints[i].method & method)
        {
            endpoints[i].possible_route = 1;
        }
        else
        {
            endpoints[i].possible_route = 0;
        }
        endpoints[i].args_found = 0;
    }

    char *uri_token;
    char *uri_token_save;
    uri_token = strtok_r(uri, delimiter, &uri_token_save);

    int route_part = 0;

    if(!uri_token)
    {
        free(uri);
        return NULL;
    }

    while(uri_token)
    {
        for(int i = 0; i < endpoints_registered; ++i)
        {
            if(!endpoints[i].possible_route)
            {
                continue;
            }
            if(!endpoints[i].route[route_part])
            {
                endpoints[i].possible_route = 0;
                continue;
            }
            if(uri_token_save[0] == '\0' && endpoints[i].route[route_part + 1])
            {
                endpoints[i].possible_route = 0;
                continue;
            }

            if(strcmp(endpoints[i].route[route_part], "{str}") == 0)
            {
                endpoints[i].possible_route += 1;

                endpoints[i].args[endpoints[i].args_found].type = ENDPOINT_ARG_TYPE_STR;
                endpoints[i].args[endpoints[i].args_found].value.v_str = uri_token;
                ++endpoints[i].args_found;
                continue;
            }
            if(strcmp(endpoints[i].route[route_part], "{int}") == 0)
            {
                char *endptr;
                errno = 0;
                int found_arg_int = strtol(uri_token, &endptr, 10);
                if(errno || (endptr && *endptr != '\0'))
                {
                    endpoints[i].possible_route = 0;
                    continue;
                }
                endpoints[i].possible_route += 2;

                endpoints[i].args[endpoints[i].args_found].type = ENDPOINT_ARG_TYPE_INT;
                endpoints[i].args[endpoints[i].args_found].value.v_int = found_arg_int;
                ++endpoints[i].args_found;
                continue;
            }
            if(strcmp(endpoints[i].route[route_part], uri_token) == 0)
            {
                endpoints[i].possible_route += 3;
                continue;
            }
            endpoints[i].possible_route = 0;
            continue;
        }
        uri_token = strtok_r(NULL, delimiter, &uri_token_save);
        ++route_part;
    }

    int best_rating = 0;
    endpoint_t *best_endpoint = NULL;
    for(int i = 0; i < endpoints_registered; ++i)
    {
        int rating = endpoints[i].possible_route;
        if(rating > best_rating)
        {
            best_endpoint = &endpoints[i];
            best_rating = best_endpoint->possible_route;
        }
    }
    
    if(best_endpoint == NULL)
    {
        free(uri);
        return NULL;
    }

    for(int i = 0; i < best_endpoint->args_count; ++i)
    {
        if(best_endpoint->args[i].type == ENDPOINT_ARG_TYPE_STR)
        {
            char *arg_value_str = malloc(sizeof(char) * (strlen(best_endpoint->args[i].value.v_str) + 1));
            strcpy(arg_value_str, best_endpoint->args[i].value.v_str);
            best_endpoint->args[i].value.v_str = arg_value_str;
        }
    }
    free(uri);

    return best_endpoint;
}

void
router_free()
{
    for(int i = 0; i < endpoints_registered; ++i)
    {
        free(endpoints[i].route_keeper);
        free(endpoints[i].route);
        if(endpoints[i].args)
        {
            free(endpoints[i].args);
        }
    }
}