Function RM_Call

app/redis-6.2.6/src/module.c:4084–4223

Exported API to call any Redis command from modules. * * * **cmdname**: The Redis command to call. * * **fmt**: A format specifier string for the command's arguments. Each * of the arguments should be specified by a valid type specification. The * format specifier can also contain the modifiers `!`, `A` and `R` which * don't have a corresponding argument. * * * `b` -- The argumen

 * This API is documented here: https://redis.io/topics/modules-intro
 */
RedisModuleCallReply *RM_Call(RedisModuleCtx *ctx, const char *cmdname, const char *fmt, ...) {
    struct redisCommand *cmd;
    client *c = NULL;
    robj **argv = NULL;
    int argc = 0, flags = 0;
    va_list ap;
    RedisModuleCallReply *reply = NULL;
    int replicate = 0; /* Replicate this command? */

    /* Handle arguments. */
    va_start(ap, fmt);
    argv = moduleCreateArgvFromUserFormat(cmdname,fmt,&argc,&flags,ap);
    replicate = flags & REDISMODULE_ARGV_REPLICATE;
    va_end(ap);

    /* Setup our fake client for command execution. */
    if (server.module_client == NULL) {
        /* This is the first RM_Call() ever. Create reusable client. */
        c = server.module_client = createClient(NULL);
    } else if (server.module_client->argv == NULL) {
        /* The reusable module client is not busy with a command. Use it. */
        c = server.module_client;
    } else {
        /* The reusable module client is busy. (It is probably used in a
         * recursive call to this module.) */
        c = createClient(NULL);
    }
    c->user = NULL; /* Root user. */
    c->flags = CLIENT_MODULE;

    /* We do not want to allow block, the module do not expect it */
    c->flags |= CLIENT_DENY_BLOCKING;
    c->db = ctx->client->db;
    c->argv = argv;
    c->argc = argc;
    if (ctx->module) ctx->module->in_call++;

    /* We handle the above format error only when the client is setup so that
     * we can free it normally. */
    if (argv == NULL) {
        errno = EBADF;
        goto cleanup;
    }

    /* Call command filters */
    moduleCallCommandFilters(c);

    /* Lookup command now, after filters had a chance to make modifications
     * if necessary.
     */
    cmd = lookupCommand(c->argv[0]->ptr);
    if (!cmd) {
        errno = ENOENT;
        goto cleanup;
    }
    c->cmd = c->lastcmd = cmd;

    /* Basic arity checks. */