# &adminguide;

## Overview

The module adds a hash table container to the configuration language. The hash table is stored in shared memory and the access to it can be done via pseudo-variables: $sht(htname=>name). The module supports definition of many hash tables and can load values at startup from a database table.

A typical use case for the SIP server is to implement a cache system in configuration file - if a value is not found in hash table, load it from database and store it in hash table so next time the access to it is very fast. In the definition of the table you can define the default expiration time of cached items. The expiration time can be adjusted per item via assignment operation at runtime.

Replication between multiple servers is performed automatically (if enabled) via the DMQ module.

You can read more about hash tables at: http://en.wikipedia.org/wiki/Hash_table.

The name can be a static string or can include pseudo- variables that will be replaced at runtime.

### Accessing $sht(htname=>key)

    ...
    modparam("htable", "htable", "a=>size=8;")
    ...
    $sht(a=>test) = 1;
    $sht(a=>$ci::srcip) = $si;
    ...

The next example shows a way to protect against dictionary attacks. If someone fails to authenticate 3 times, it is forbidden for 15 minutes. Authentication against database is expensive as it does a select on the subscriber table. By disabling the DB auth for 15 minutes, resources on the server are saved and time to discover the password is increased substantially. Additional alerting can be done by writing a message to syslog or sending email, etc.

To implement the logic, two hash table variables are used: one counting the failed authentications per user and one for storing the time of the last authentication attempt. To ensure a unique name per user, the hash table uses a combination of authentication username and text ::auth_count and ::last_auth.

### Dictionary attack limitation

    ...
    modparam("htable", "htable", "a=>size=8;")
    ...
    if(is_present_hf("Authorization"))
    {
        if($sht(a=>$au::auth_count)==3)
        {
    		$var(exp) = $Ts - 900;
            if($sht(a=>$au::last_auth) > $var(exp))
            {
                sl_send_reply("403", "Try later");
                exit;
            } else {
                $sht(a=>$au::auth_count) = 0;
            }
        }
        if(!www_authenticate("$td", "subscriber"))
        {
            switch ($retcode) {
                case -1:
                    sl_send_reply("403", "Forbidden");
                exit;
                case -2:
                    if($sht(a=>$au::auth_count) == $null)
                        $sht(a=>$au::auth_count) = 0;
                    $sht(a=>$au::auth_count) = $sht(a=>$au::auth_count) + 1;
                    if($sht(a=>$au::auth_count) == 3)
                        xlog("auth failed 3rd time - src ip: $si\n");
                    $sht(a=>$au::last_auth) = $Ts;
                break;
            }
            www_challenge("$td"/*realm*/,"0"/*qop*/);
            exit;
        }
        $sht(a=>$au::auth_count) = 0;
    } else {
        www_challenge("$td","0");
        exit;
    }
    ...

The module also provides a way to store multiple values for a single key. This is emulated by storing individual keys as 'key_name[n]', where n is incremented for each key. The total number of keys is stored in a dedicated key, by default: 'key_name::size'.

The array is built when the table is loaded in memory and afterwards all the keys are treated as individual keys. If a particular entry in the array is deleted, it is the administrator's responsibility to update the size of the array and any other elements (if required).

### Storing array values

    # Example of dbtext with multiple keys
    $ cat /usr/local/etc/kamailio/dbtext/htable
    1:key:1:0:value3:0
    2:key:1:0:value2:0
    3:key:1:0:value1:0

    # The array key will be loaded in memory in the following format:
    $ kamctl rpc htable.dump htable
    {
            entry: 35
            size: 1
            slot: {
                    item: {
                            name: key[0]
                            value: value1
                    }
            }
    }
    {
            entry: 50
            size: 1
            slot: {
                    item: {
                            name: key::size
                            value: 3
                    }
            }
    }
    {
            entry: 67
            size: 1
            slot: {
                    item: {
                            name: key[1]
                            value: value2
                    }
            }
    }
    {
            entry: 227
            size: 1
            slot: {
                    item: {
                            name: key[2]
                            value: value3
                    }
            }
    }

    # Now let's delete a particular entry in the array: key[0].
    $ kamctl rpc htable.delete htable key[0]

    # The array key will look like this after a key was deleted:
    $ kamctl rpc htable.dump htable
    {
            entry: 50
            size: 1
            slot: {
                    item: {
                            name: key::size
                            value: 3
                    }
            }
    }
    {
            entry: 67
            size: 1
            slot: {
                    item: {
                            name: key[1]
                            value: value2
                    }
            }
    }
    {
            entry: 227
            size: 1
            slot: {
                    item: {
                            name: key[2]
                            value: value3
                    }
            }
    }

## Dependencies

### &kamailio; Modules

The following modules must be loaded before this module:

- If DMQ replication is enabled, the DMQ module must be loaded first..

### External Libraries or Applications

The following libraries or applications must be installed before running &kamailio; with this module loaded:

- None.

### Loading from database

The module is able to load values in a hash table at startup upon providing a DB URL and table name.

The structure of the table must contain:

- key name - string containing the name of the key.

- key type - the type of the key

  - 0 - simple key - the key is added as 'key_name'.

  - 1 - array key - the key is added as 'key_name[n]' - n is incremented for each key with this name to build an array in hash table. In addition, an additional key is built to hold the total number of key in the array, by default key_name::size (see array_size_suffix parameter).

- value type - the type of the key value

  - 0 - value is string.

  - 1 - value is integer.

- key value - string containing the value of the key.

## Parameters

### `htable` (str)

The definition of a hash table. The value of the parameter may have the following format:

- "htname=>size=_number_;autoexpire=_number_;dbtable=_string_"

The parameter can be set multiple times to get more hash tables in same configuration file.

- htname - string specifying the name of the hash table. This string is used by $sht(...) to refer to the hash table.

- size - number to control how many slots (buckets) to create for the hash table. Larger value means more slots with higher probability for less collisions. The actual number slots (or buckets) created for the table is 2^size. The possible range for this value is from 2 to 31, smaller or larger values will be increased to 3 (8 slots) or decreased to 14 (16384 slots). Note that each slot can store more than one item, when there are collisions of hash ids computed for keys. The items in the same slot are stored in a linked list. In other words, the size is not setting a limit of how many items can be stored in a hash table, as long as there is enough free shared memory, new items can be added.

- autoexpire -time in seconds to delete an item from a hash table if no update was done to it. If it is missing or set to 0, the items won't expire.

- dbtable - name of database to be loaded at startup in hash table. If empty or missing, no data will be loaded.

- cols - the column names of the database table. They must be enclosed in quotes in order to form a valid SIP parameter value and be separated by comma. The first column corresponds to key_name. When specified, there must be at least two columns. If this attribute is not specified, then the global module parameters for column names are used. If more than one value columns are specified, the hash table will pack the column values in a comma separated string, which will be associated with the key (string transformation {s.select,...} can be used in configuration file to extract a specific column value). When cols attribute is present, writing back to database table is disabled.

- dbmode - if set to 1, the content of hash table is written to database table when the SIP server is stopped (i.e., ensure persistency over restarts). Default value is 0 (no write back to db table).

- initval - the integer value to be returned instead of $null when a requested key is not set.

- updateexpire - if set to 1 (default), the time until expiration of an item is reset when that item is updated. Certain uses of htable may dictate that updates should not reset the expiration timeout, however, in which case this attribute can be set to 0.

- dmqreplicate - if set to 1, any actions (set, update, delete etc.) performed upon entries in this table will be replicated to other nodes (htable peers). Please note, module parameter enable_dmq must also be set in order for this to apply (see below). Default is 0 (no replication).

- coldelim - the character delimeter to use when packing the htable. When set, this parameter changes the column delimeter between columns in a multiple column hash table. This can be useful when loading JSON data types into a hash table as they conflict with the default , delimeter, allowing these values to be parsed in the routing config. See the example below on parsing a JSON array from an htable with ; as the column delimeter.

      ...
      modparam("htable", "htable", "customer=>size=8;dbtable=customer;cols='dids,description';coldelim=';'")
      ...
      $avp(customer) = $sht(customer=>1);
      $var(customer_dids) = $(avp(customer){s.select,0,;});
      $var(customer_desc) = $(avp(customer){s.select,1,;});
      ...

- colnull - the character to use when packing a NULL value into the htable from the database. This parameter can be set to the empty string or a single character. This can be used to simplify checking a single column in a row for emptiness, in the routing config. The example below shows how one would do that.

      ...
      modparam("htable", "htable", "customer=>size=8;dbtable=customer;cols='name,description';colnull=''")
      ...
      $avp(customer) = $sht(customer=>1);
      $var(customer_name) = $(avp(customer){s.select,0,;});
      if (!strempty($var(customer_name))) {
      ...
      }

Default value is NULL.

#### Set `htable` parameter

    ...
    modparam("htable", "htable", "a=>size=4;autoexpire=7200;dbtable=htable_a;")
    modparam("htable", "htable", "b=>size=5;")
    modparam("htable", "htable", "c=>size=4;autoexpire=7200;initval=1;dmqreplicate=1;")
    ...

### `db_url` (str)

The URL to connect to database for loading values in hash table at start up.

Default value is NULL (do not connect).

#### Set `db_url` parameter

    ...
    modparam("htable", "db_url", "&defaultdb;")
    ...

### `key_name_column` (str)

The name of the column containing the hash table key name.

Default value is 'key_name'.

#### Set `key_name_column` parameter

    ...
    modparam("htable", "key_name_column", "kname")
    ...

### `key_type_column` (str)

The name of the column containing the hash table key type.

Default value is 'key_type'.

#### Set `key_type_column` parameter

    ...
    modparam("htable", "key_type_column", "ktype")
    ...

### `value_type_column` (str)

The name of the column containing the hash table value type.

Default value is 'value_type'.

#### Set `value_type_column` parameter

    ...
    modparam("htable", "value_type_column", "vtype")
    ...

### `key_value_column` (str)

The name of the column containing hash table key value.

Default value is 'key_value'.

#### Set `key_value_column` parameter

    ...
    modparam("htable", "key_value_column", "kvalue")
    ...

### `expires_column` (str)

The name of the column containing the expires value.

Default value is 'expires'.

#### Set `expires_column` parameter

    ...
    modparam("htable", "expires_column", "expiry")
    ...

### `array_size_suffix` (str)

The suffix to be added to store the number of items in an array (see key type).

Default value is '::size'.

#### Set `array_size_suffix` parameter

    ...
    modparam("htable", "array_size_suffix", "-count")
    ...

### `fetch_rows` (integer)

How many rows to fetch at once from database.

Default value is 100.

#### Set `fetch_rows` parameter

    ...
    modparam("htable", "fetch_rows", 1000)
    ...

### `timer_interval` (integer)

Interval in seconds to check for expired htable values.

Default value is 20.

#### Set `timer_interval` parameter

    ...
    modparam("htable", "timer_interval", 10)
    ...

### `db_expires` (integer)

If set to 1, the module loads/saves the value for expire of the items in hash table from/to database. It applies only to hash tables that have the auto-expires attribute defined. If set to 0, only the key name and the value are loaded, the expires for each item being set to 0.

Note that the module is not reloading automatically the items from database when they expire, the reloading can be done only via RPC command.

Default value is 0.

#### Set `db_expires` parameter

    ...
    modparam("htable", "db_expires", 1)
    ...

### `enable_dmq` (integer)

If set to 1, will enable DMQ replication of actions performed upon entries in all tables having "dmqreplicate" parameter set. Any update action performed via pseudo-variables and RPC commands will be repeated on all other nodes. Therefore, it is important to ensure the table definition (size, autoexpire etc.) is identical across all instances.

Important: If this parameter is enabled, the DMQ module must be loaded first - otherwise, startup will fail.

Currently, values are not replicated on load from DB as it is expected that in these cases, all servers will load their values from the same DB.

Default value is 0.

#### Set `enable_dmq` parameter

    ...
    modparam("htable", "enable_dmq", 1)
    ...

### `dmq_init_sync` (integer)

If set to 1, will request synchronization from other nodes at startup. It applies to all tables having the "dmqreplicate" parameter set. As above, it is important to ensure the definition (size, autoexpire etc.) of replicated tables is identical across all instances.

Default value is 0.

#### Set `dmq_init_sync` parameter

    ...
    modparam("htable", "dmq_init_sync", 1)
    ...

### `timer_procs` (integer)

If set to 1 or greater, the module will create its own timer processes to scan for expired items in hash tables. If set to zero, it will use the core timer for this task. Set it to 1 if you store a lot of items with autoexpire property.

Default value is 0.

#### Set `timer_procs` parameter

    ...
    modparam("htable", "timer_procs", 4)
    ...

### `event_callback` (str)

The name of the function in the kemi configuration file (embedded scripting language such as Lua, Python, ...) to be executed instead of event_route[...] blocks.

The function receives a string parameter with the name of the event, the values can be: 'htable:mod-init', 'htable:expired:htname' ('htname' being the name of hash table).

Default value is 'empty' (no function is executed for events).

#### Set `event_callback` parameter

    ...
    modparam("htable", "event_callback", "ksr_htable_event")
    ...
    -- event callback function implemented in Lua
    function ksr_htable_event(evname)
    	KSR.info("===== htable module triggered event: " .. evname .. "\n");
    	return 1;
    end
    ...

### `event_callback_mode` (int)

Control when event_route[htable:init] is executed: 0 - after all modules were initialized; 1 - in first worker process.

Set it to 1 if used in a KEMI script or when needing to use database (e.g., via sqlops) inside event_route[htable:init].

Default value is 0.

#### Set `event_callback_mode` parameter

    ...
    modparam("htable", "event_callback_mode", 1)
    ...

## Functions

### `sht_print()`

Dump content of hash table to L_ERR log level. Intended for debug purposes.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE, ONREPLY_ROUTE, BRANCH_ROUTE.

#### `sht_print` usage

    ...
    sht_print();
    ...

### `sht_rm(htname, itname)`

Delete the item with the name 'itname' from hash table 'htname'. This API function is equivalent to '$sht(htname=>itname) = $null'.

This function can be used from ANY_ROUTE.

#### `sht_rm` usage

    ...
    sht_rm("ha", "test"");
    ...

### `sht_rm_name_re(htable=>regexp)`

Delete all entries in the htable that match the name against regular expression.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE, ONREPLY_ROUTE, BRANCH_ROUTE.

#### `sht_rm_name_re` usage

    ...
    sht_rm_name_re("ha=>.*");
    ...

### `sht_rm_value_re(htable=>regexp)`

Delete all entries in the htable that match the value against regular expression.

This function can be used from REQUEST_ROUTE, FAILURE_ROUTE, ONREPLY_ROUTE, BRANCH_ROUTE.

#### `sht_rm_value_re` usage

    ...
    sht_rm_value_re("ha=>.*");
    ...

### `sht_rm_name(htable, op, val)`

Delete all entries in the htable that match the name against the val parameter.

The op parameter can be:

- re - match the val parameter as regular expression.

- sw - match the val parameter as 'starts with'.

- ew - match the val parameter as 'ends with'.

- in - match the val parameter as 'includes'.

All parameters can be static strings or contain variables.

This function can be used from ANY_ROUTE.

#### `sht_rm_name` usage

    ...
    sht_rm_name("ha", "re", ".*");
    ...

### `sht_rm_value(htable, op, val)`

Delete all entries in the htable that match the value against the val parameter.

The op parameter can be:

- re - match the val parameter as regular expression.

- sw - match the val parameter as 'starts with'.

- ew - match the val parameter as 'ends with'.

- in - match the val parameter as 'includes'.

All parameters can be static strings or contain variables.

This function can be used from ANY_ROUTE.

#### `sht_rm_value` usage

    ...
    sht_rm_value("ha", "re", ".*");
    ...

### `sht_setxs(htname, itname, itval, exval)`

Set the item with the name 'itname' from hash table 'htname' to string value 'itval' and expire property to 'exval'.

The parameters can be with variables.

This function can be used from ANY_ROUTE.

#### `sht_setxs` usage

    ...
    sht_setxs("ha", "test", "abc", "10");
    ...

### `sht_setxi(htname, itname, itval, exval)`

Set the item with the name 'itname' from hash table 'htname' to integer value 'itval' and expire property to 'exval'.

The parameters can be with variables.

This function can be used from ANY_ROUTE.

#### `sht_setxi` usage

    ...
    sht_setxs("ha", "test", "100", "10");
    ...

### `sht_reset(htable)`

Delete all entries in the htable. The name of the hash table can be a dynamic string with variables.

This function can be used from ANY_ROUTE.

#### `sht_reset` usage

    ...
    sht_reset("ha$var(x)");
    ...

### `sht_lock(htable=>key)`

Lock the slot in htable corresponding to the key item. Note that the locking is re-entrant for the process, therefore the lock and unlock should be done by the same process.

This function can be used from ANY_ROUTE.

#### `sht_lock` usage

    ...
    sht_lock("ha=>test");
    ...

### `sht_unlock(htable=>key)`

Unlock the slot in htable corresponding to the key item. Note that the locking is re-entrant for the process, therefore the lock and unlock should be done by the same process.

This function can be used from ANY_ROUTE.

#### `sht_unlock` usage

    ...
    sht_lock("ha=>test");
    $sht(ha=>test) = $sht(ha=>test) + 10;
    sht_unlock("ha=>test");
    ...

### `sht_iterator_start(iname, hname)`

Start an iterator for hash table named by the value of parameter hname. The parameter iname is used to identify the iterator. There can be up to 4 iterators at the same time, with different name.

Both parameters can be dynamic strings with variables.

IMPORTANT: the slot of the hash table is left locked when retrieving in item. Therefore be sure you do not update the content of the hash table in between sht_iterator_start() and sht_iterator_end(), because it may end up in dead lock.

This function can be used from ANY_ROUTE.

#### `sht_iterator_start` usage

    ...
    sht_iterator_start("i1", "h1");
    ...

### `sht_iterator_end(iname)`

Close the iterator identified by iname parameter and release the hash table slot acquired by the iterator. The iname value must be the same used for sht_iterator_start().

The parameter can be dynamic string with variables.

This function can be used from ANY_ROUTE.

#### `sht_iterator_end` usage

    ...
    sht_iterator_end("i1");
    ...

### `sht_iterator_next(iname)`

Move the iterator to the next item in hash table. It must be called also after sht_iterator_start() to get the first item in the hash table. Items are returned as they are found in the hash table slot, starting with the first slot.

The return code is false when there is no (more) item in the hash table.

The item name and value are accessible via variables: $shtitkey(iname) and $shtitval(iname).

The parameter can be dynamic string with variables.

This function can be used from ANY_ROUTE.

#### `sht_iterator_next` usage

    ...
        sht_iterator_start("i1", "h1");
        while(sht_iterator_next("i1")) {
            xlog("h1[$shtitkey(i1)] is: $shtitval(i1)\n");
        }
        sht_iterator_end("i1");
    ...

### `sht_iterator_rm(iname)`

Remove the current item in the iterator and move the iterator to the next one.

The return code is 1 (true) if the item was removed and next item exists; -2 (false) if the item was removed and there is no next item (end of items); other negative value (false) can be returned on error (e.g., iterator or item not found).

The parameter can be dynamic string with variables.

This function can be used from ANY_ROUTE.

#### `sht_iterator_rm` usage

    ...
        sht_iterator_start("i1", "h1");
        while(sht_iterator_next("i1")) {
            while($shtitkey(i1) =~ "xyz" and sht_iterator_rm("i1")) {
                xdbg("item removed\n");
            }
        }
        sht_iterator_end("i1");
    ...

### `sht_iterator_sets(iname, sval)`

Set the value of the current item to the string in the sval.

The parameters can be dynamic strings with variables.

This function can be used from ANY_ROUTE.

#### `sht_iterator_sets` usage

    ...
        sht_iterator_start("i1", "h1");
        sht_iterator_next("i1");
        sht_iterator_sets("i1", "$ci");
        sht_iterator_end("i1");
    ...

### `sht_iterator_seti(iname, ival)`

Set the value of the current item to the integer in the ival.

The parameters can be dynamic strings or integers with variables.

This function can be used from ANY_ROUTE.

#### `sht_iterator_seti` usage

    ...
        sht_iterator_start("i1", "h1");
        sht_iterator_next("i1");
        sht_iterator_seti("i1", "20");
        sht_iterator_end("i1");
    ...

### `sht_iterator_setex(iname, exval)`

Set the expire of the current item to the integer in the exval.

The parameters can be dynamic strings or integers with variables.

This function can be used from ANY_ROUTE.

#### `sht_iterator_setex` usage

    ...
        sht_iterator_start("i1", "h1");
        sht_iterator_next("i1");
        sht_iterator_setex("i1", "120");
        sht_iterator_end("i1");
    ...

### `sht_match_name(htable, op, mval)`

Return greater than 0 (true) if the htable has an item that matches the name against the mval parameter.

The op parameter can be:

- eq - match the val parameter as string equal expression.

- ne - match the val parameter as string not-equal expression.

- re - match the val parameter as regular expression.

- sw - match the val parameter as 'starts with' expression.

All parameters can be static strings or contain variables.

This function can be used from ANY_ROUTE.

#### `sht_match_name` usage

    ...
    if(sht_match_name("ha", "eq", "alice")) {
      ...
    }
    ...

### `sht_has_name(htable, op, mval)`

Alias for sht_match_name().

### `sht_match_str_value(htable, op, mval)`

Return greater than 0 (true) if the htable has an item that matches the string value against the mval parameter.

The op parameter can be:

- eq - match the val parameter as string equal expression.

- ne - match the val parameter as string not-equal expression.

- re - match the val parameter as regular expression.

- sw - match the val parameter as 'starts with' expression.

All parameters can be static strings or contain variables.

This function can be used from ANY_ROUTE.

#### `sht_match_name` usage

    ...
    if(sht_match_str_value("ha", "eq", "alice")) {
      ...
    }
    ...

### `sht_has_str_value(htable, op, mval)`

Alias for sht_match_str_value().

### `sht_is_null(htname, itname)`

Check if the item with the name 'itname' from hash table 'htname' exists. This API function is equivalent to '($sht(htname=>itname) == $null)'.

This function returns:

- 3 - if parameters could not be parsed

- 2 - if hash table is null

- 1 - if the value is null

- -1 - if hash table default is non null

- -2 - if the value is not null

All parameters can be static strings or contain variables.

This function can be used from ANY_ROUTE.

#### `sht_is_null` usage

    ...
    if (sht_is_null("my_ht", "my_key")) {
        xlog("L_ERR", "could not find my_key in my_ht\n");
    }
    ...

### `sht_inc(htname, itname)`

Atomically increment the value of 'itname' in hash table 'htname'. This API function is similar to '$shtinc(htname=>itname)', without returning the value.

This function returns 1 on successful increment or -1 otherwise.

All parameters can be static strings or contain variables.

This function can be used from ANY_ROUTE.

#### `sht_inc` usage

    ...
    if (!sht_inc("my_ht", "my_key")) {
        xlog("L_ERR", "could not increment my_key\n");
    }
    ...

### `sht_dec(htname, itname)`

Atomically decrement the value of 'itname' in hash table 'htname'. This API function is similar to '$sht_dec(htname=>itname)', without returning the value.

This function returns 1 on successful decrement or -1 otherwise.

All parameters can be static strings or contain variables.

This function can be used from ANY_ROUTE.

#### `sht_dec` usage

    ...
    if (!sht_dec("my_ht", "my_key")) {
        xlog("L_ERR", "could not decrement my_key\n");
    }
    ...

## Exported pseudo-variables

- $sht(htable=>key)

- $shtex(htable=>key)

- $shtcn(htable=>key)

- $shtcv(htable=>key)

- $shtinc(htable=>key)

- $shtdec(htable=>key)

- $shtitkey(iname)

- $shtitval(iname)

- $shtrecord(attribute)

Exported pseudo-variables are documented at &kamwikilink;.

## RPC Commands

### `htable.get htable key`

Lists one value in a hash table

Name: htable.get

Parameters:

- htable : Name of the hash table to dump

- key : Key name of the hash table value to dump. Note: if key name is an integer value, it should be prefixed with s:

Example:

    ...
    # Dump $sht(students=>alice)
    kamctl rpc htable.get students alice

    # Dump $sht(students=>15)
    kamctl rpc htable.get students s:15

    # Dump first entry in array key course $sht(students=>course[0])
    kamctl rpc htable.get students course[0]
    ...

### `htable.delete htable key`

Delete one value in a hash table

Name: htable.delete

Parameters:

- htable : Name of the hash table to delete

- key : Key name of the hash table value to delete. Note: if key name is an integer value, it should be prefixed with s:

Example:

    ...
    # Delete $sht(students=>alice)
    kamctl rpc htable.delete students alice

    # Delete $sht(students=>15)
    kamctl rpc htable.delete students s:15

    # Delete first entry in array key course $sht(students=>course[0])
    kamctl rpc htable.delete students course[0]
    ...

### `htable.sets htable key value`

Set an item in hash table to string value.

Name: htable.sets

Parameters:

- htable : Name of the hash table

- key : Key name in the hash table. Note: if key name is an integer value, it should be prefixed with s:

- Value : String value for the item

Example:

    ...
    # Set $sht(test=>x) as string
    kamctl rpc htable.sets test x abc

    # Set $sht(test=>5) as string
    kamctl rpc htable.sets test s:5 abc

    # Set firsti entry in array key x $sht(test=>x[0]) as string
    kamctl rpc htable.sets test x[0] abc
    ...

### `htable.seti htable key value`

Set an item in hash table to integer value.

Name: htable.seti

Parameters:

- htable : Name of the hash table

- key : Key name in the hash table. Note: if key name is an integer value, it should be prefixed with s:

- Value : Integer value for the item

Example:

    ...
    # Set $sht(test=>x) as integer
    kamctl rpc htable.seti test x 123

    # Set $sht(test=>5) as integer
    kamctl rpc htable.seti test s:5 123

    # Set first entry in array key x $sht(test=>x[0]) as integer
    kamctl rpc htable.seti test x[0] 123
    ...

### `htable.setex htable key expire`

Set the expire for an item in hash table.

Name: htable.setex

Parameters:

- htable : name of the hash table

- key : key name in the hash table. Note: if key name is an integer value, it should be prefixed with s:

- expire : integer value for the expire (seconds)

Example:

    ...
    # set expire for $sht(test=>x) to 120 secs
    kamctl rpc htable.setex test x 120

    # set expire for $sht(test=>10) to 120 secs
    kamctl rpc htable.setex test s:10 120
    ...

### `htable.setxs htable key value expire`

Set the string value and expire for an item in hash table.

Name: htable.setxs

Parameters:

- htable : name of the hash table

- key : key name in the hash table. Note: if key name is an integer value, it should be prefixed with s:

- value : string value for the item

- expire : integer value for the expire (seconds)

Example:

    ...
    # set value to 'abc' and expire for $sht(test=>x) to 120 secs
    kamctl rpc htable.setxs test x abc 120

    # set value to 'abc' and expire for $sht(test=>10) to 120 secs
    kamctl rpc htable.setxs test s:10 abc 120
    ...

### `htable.setxi htable key value expire`

Set the integer value and expire for an item in hash table.

Name: htable.setxi

Parameters:

- htable : name of the hash table

- key : key name in the hash table. Note: if key name is an integer value, it should be prefixed with s:

- value : integer value for the item

- expire : integer value for the expire (seconds)

Example:

    ...
    # set value to 10 and expire for $sht(test=>x) to 120 secs
    kamctl rpc htable.setxi test x 10 120

    # set value to 10 and expire for $sht(test=>5) to 120 secs
    kamctl rpc htable.setxi test s:5 10 120
    ...

### `htable.dump htable`

Lists all the values in a hash table

Name: htable.dump

Parameters:

- htable : Name of the hash table to dump

Example:

    ...
    kamctl rpc htable.dump ipban
    ...

### `htable.reload htable`

Reload hash table from database.

Name: htable.reload

Parameters:

- htable : Name of the hash table to reload

Example:

    ...
    kamctl rpc htable.reload ipban
    ...

### `htable.store htable`

Store hash table to database.

Name: htable.store

Parameters:

- htable : Name of the hash table to store

Example:

    ...
    kamctl rpc htable.store ipban
    ...

### `htable.flush htable`

Empty the hash table

Name: htable.flush

Parameters:

- htable : Name of the hash table to flush

Example:

    ...
    kamctl rpc htable.flush ipban
    ...

### `htable.listTables`

Lists all defined tables

Name: htable.listTables

Parameters:

- None

Example:

    ...
    kamctl rpc htable.listTables
    ...

### `htable.stats`

Get statistics for hash tables - name, number of slots, number of items, max number of items per slot, min number of items per slot.

Name: htable.stats

Parameters:

- None

Example:

    ...
    kamctl rpc htable.stats
    ...

### `htable.dmqsync [htable]`

Perform a DMQ sync action.

Name: htable.dmqsync

Parameters:

- htable: name of the hash table to perform dmq sync for. If not provided, sync is performed for all hash tables that have dmq sync enabled.

Example:

    ...
    kamctl rpc htable.dmqsync
    kamctl rpc htable.dmqsync ipban
    ...

### `htable.dmqresync htable`

Perform a resync action (flush and dmq sync).

Name: htable.dmqresync

Parameters:

- htable: name of the hash table to perform resync for.

Example:

    ...
    kamctl rpc htable.dmqresync ipban
    ...

## Event routes

### `htable:mod-init`

When defined, the module calls event_route[htable:mod-init] after all modules have been initialized. A typical use case is to initialise items in hash tables. The event route is executed only once, after core and module initialization, but before &kamailio; forks any child processes.

Note: do not expect to use functions from all other modules here, even if they are loaded before the htable module, because many of them initialize their runtime structures inside child init callbacks, which are executed after this moment, when forking child processes. For example, sqlops cannot be used, connections to database are initialized in child init. Even more, it is recommended not to use functions from other modules, because it can mess up what they created in mod init callback and expect in child init callback. It should be ok to use functions from htable module or assignment operations.

    ...
    event_route[htable:mod-init] {
        $sht(a=>x) = 1;
    }
    ...

### `htable:expired:<table>`

When defined, the module calls event_route[htable:expired:<table>] when an entry in the given table expires. In this event route, the key and value of the expired record are available with the $shtrecord(key) and $shtrecord(value) pseudo-variables.

    ...

    event_route[htable:expired:mytable] {
        xlog("mytable record expired $shtrecord(key) => $shtrecord(value)\n");
    }
    ...