# &adminguide;

## Overview

This module implements generic string translations based on matching and replacement rules. It can be used to manipulate the request URI or a PV and to translate it to a new format/value. Dialplan can also be used to match a given URI and retrieve a set of attributes based on the match. It is a very flexible module that can be used to handle call routing, prefix rewrites and much more.

## How it works

At startup the module will load a set of matching and transformation rules from a database. Rules are grouped into dialplans. Every database row will be stored in memory as a dialplan rule. Each rule will describe how the matching will be made, how the input value will be modified and which attributes that will be set for the matching transformation.

The module expects an input value which will be matched against a rule by using regular expressions (see 'man pcresyntax' for syntax), string or fnmatch (see 'man fnmatch') matching. Overlapping matching expressions can be controlled via priorities. One priority can have multiple dialplan entries. Priorities need not be numbered with consecutive numbers. The next higher priority will be used after trying to match all entries in one priority.

Once a rule is matched, the defined transformation (if any) is applied and the result is returned as output value. Also, if any string attribute is associated to the rule, this will be returned to the script along with the output value. This can be used to identify the used rule.

The first matching rule will be processed.

## Dialplan use cases

The module can be used to implement multiple dialplans - to do auto-completion of dialed numbers (like national to international), to convert generic numbers to specific numbers (like for emergency numbers).

The module can also be used for detecting a range or sets of numbers mapped on a service/case - the attribute string can be used to store extra information about the service/case.

Non-SIP string translation can be implemented - like converting country names from all possible formats to a canonical format: (UK, England, United Kingdom) -> GB.

Any other string-base translation or detection for whatever other purposes.

## Dependencies

### &kamailio; Modules

The following modules must be loaded before this module:

- A database module

### External Libraries or Applications

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

- libpcre - the libraries of PCRE.

## Parameters

### `db_url` (string)

The translation rules will be loaded using this database URL.

Default value is &defaultdb;.

#### Set `db_url` parameter

    ...
    modparam("dialplan", "db_url", "mysql://user:passwd@localhost/db")
    ...

### `table_name` (string)

The name of the database table used to load the translation rules.

Default value is dialplan.

#### Set `table_name` parameter

    ...
    modparam("dialplan", "table_name", "my_table")
    ...

### `dpid_col` (string)

The column name used to store the dialplan group ID.

Default value is dpid.

#### Set `dpid_col` parameter

    ...
    modparam("dialplan", "dpid_col", "column_name")
    ...

### `pr_col` (string)

The column name used to store the priority of the corresponding rule from the database row.

Default value is pr.

#### Set `pr_col` parameter

    ...
    modparam("dialplan", "pr_col", "column_name")
    ...

### `match_op_col` (string)

The column name used to store the type of matching of the rule.

Default value is match_op.

#### Set `match_op_col` parameter

    ...
    modparam("dialplan", "match_op_col", "column_name")
    ...

### `match_exp_col` (string)

The column name to store the rule match expression.

Default value is match_exp.

#### Set `match_exp_col` parameter

    ...
    modparam("dialplan", "match_exp_col", "column_name")
    ...

### `match_len_col` (string)

The column name to store the length of a string matching the match expression.

Default value is match_len.

#### Set `pr_col` parameter

    ...
    modparam("dialplan", "match_len_col", "column_name")
    ...

### `subst_exp_col` (string)

The column name to store the rule's substitution expression.

Default value is subst_exp.

#### Set `pr_col` parameter

    ...
    modparam("dialplan", "subst_exp_col", "column_name")
    ...

### `repl_exp_col` (string)

The column name to store the rule's replacement expression.

Default value is repl_exp.

#### Set `repl_exp_col` parameter

    ...
    modparam("dialplan", "repl_exp_col", "column_name")
    ...

### `attrs_col` (string)

The column name to store the rule's attributes to be set after match (see `attrs_pvar` )

Default value is attrs.

#### Set `attrs_col` parameter

    ...
    modparam("dialplan", "attrs_col", "column_name")
    ...

### `attrs_pvar` (string)

The pseudovariable used to store the rule's attributes, after translation (when `dp_translate`() succeeds). This parameter can be an AVP or a script variable ($var())..

Default value is NULL.

#### Set `attrs_pvar` parameter

    ...
    modparam("dialplan", "attrs_pvar", "$avp(s:dest)")
    ...

### `fetch_rows` (int)

The number of rows to be fetched at once from database

Default value is 1000.

#### Set `fetch_rows` parameter

    ...
    modparam("dialplan", "fetch_rows", 4000)
    ...

### `match_dynamic` (int)

If set to 1, the match and substitution expressions can include script variables and their values are evaluated at runtime.

During the loading process, the values that contain variables are no longer pre-compiled to PCRE structure in memory, because the values change at runtime, thus expect slightly slower performances. Values without script variables are pre-compiled even if this parameter is enabled.

Default value is 0 (disabled).

#### Set `match_dynamic` parameter

    ...
    modparam("dialplan", "match_dynamic", 1)
    ...

### `append_branch` (int)

If set to 1, the module appends a new outgoing branch when request URI (r-uri) or its user part are changed by dp_translate() or dp_replace() inside a failure_route block. Set it to 0 if the branch should not be added.

Default value is 1.

#### Set `append_branch` parameter

    ...
    modparam("dialplan", "append_branch", 0)
    ...

### `reload_delta` (int)

The number of seconds that have to be waited before executing a new reload of dialplan rules. By default there is a rate limiting of maximum one reload in five seconds.

If set to 0, no rate limit is configured. Note carefully: use this configuration only in tests environments because executing two dialplan reloads at the same time can cause to kamailio to crash.

Default value is 5.

#### Set `reload_delta` parameter

    ...
    modparam("dialplan", "reload_delta", 1)
    ...

## Functions

### `dp_replace(dpid, inval, outvar)`

The function translates the input value 'inval' using the rules with dialplan id 'dpid', storing the value in the variable 'outvar'. If the rule that was applied has attributes, they are stored in the variable provided via the module parameter 'attrs_pvar'.

The behavior is same as dp_translate("dpid", "inval/outvar"), but the parameters have a more flexible format.

Meaning of the parameters is as follows:

- dpid - the dialplan id to match the rules and apply the transformations. It can be a static string or a config variable holding an integer value.

- inval - input value. It can be a static or a dynamic string. The dynamic string can contain config variables, combined or not with static strings, that are evaluated at runtime.

- outvar - output variable name. The value resulted after applying the matching rule is stored in this variable. The name must refer to a writable variable.

This function can be used from ANY_ROUTE.

#### `dp_replace` usage

    ...
    dp_replace("240", "$rU", "$var(newru)");
    xlog("'$rU' was translated to '$var(newru)'\n");
    dp_replace("240", "+49$rU", "$var(newval)");
    ...

### `dp_match(dpid, inval)`

The function matches the input value 'inval' using the rules with dialplan id 'dpid'. If the rule that was applied has attributes, they are stored in the variable provided via the module parameter 'attrs_pvar'.

The behavior is same as dp_translate("dpid", "inval"), but the parameters have a more flexible format.

Meaning of the parameters is as follows:

- dpid - the dialplan id to match the rules and apply the transformations. It can be a static string or a config variable holding an integer value.

- inval - input value. It can be a static or a dynamic string. The dynamic string can contain config variables, combined or not with static strings, that are evaluated at runtime.

This function can be used from ANY_ROUTE.

#### `dp_match` usage

    ...
    dp_match("240", "+49$rU");
    xlog("the attributes associated with '+49$rU' are '$var(attrs)'\n");
    ...

### `dp_translate(id, [src[/dest]])`

Will try to translate src into dest according to the translation rules in the dialplan identified by id . If src/dest is missing the default parameter ruri.user/ruri.user will be used, thus translating the request URI user part. If only dest is missing, only matching and storing of the matching rule's attributes is done.

Returns 1, if translation succeeded, -1 in case of some error occurred, and -2 if dialplan with ID equal to id does not exist.

Meaning of the parameters is as follows:

- id -the dialplan id of the possible matching rules. This parameter can have the following types:

  - integer- the dialplan id is statically assigned

  - avp var - the dialplan id is the value of an existing avp variable

  - script var - the dialplan id is the value of an existing script variable.

- src/dest - input and output of the function.

  Input parameter src can be any pseudo variable. Output parameter dest can be:

  - R-URI

    - the string is the r-uri or r-uri user part

  - avp var

    - At input the function will get the input string from an existing avp variable. At output the function will add an avp with the value of the output string.

  - script var

    - At input the function will get the input string from an existing script variable. At output the function will set a script variable with the value of the output string.

This function can be used from ANY_ROUTE.

#### `dp_translate` usage

    ...
    dp_translate("240", "$ruri.user/$avp(s:dest)");
    xlog("translated to var $avp(s:dest) \n");
    ...

#### `dp_translate` usage

    ...
    $avp(s:src) = $ruri.user;
    dp_translate("$var(x)", "$avp(s:src)/$var(y)");
    xlog("translated to var $var(y) \n");
    ...

### `dp_reload()`

Reload the translation rules from the database. Note that there is a rate limiting defined by 'reload_delta' parameter. By default is allowed maximum one reload in five seconds.

Name: dp_reload

Parameters: none

This function can be used from ANY_ROUTE.

## RPC Commands

### `dialplan.dump`

Dumps the content of one dialplan ID

Name: dialplan.dump

Parameters: Dialplan ID

Example:

    		&kamctl; rpc dialplan.dump 100

### `dialplan.reload`

Perform a reload of the translation rules from the database. Note that there is a rate limiting defined by 'reload_delta' parameter. By default is allowed maximum one reload in five seconds.

Name: dialplan.reload

Parameters: none

Example:

    		&kamctl; rpc dialplan.reload

### `dialplan.translate`

Will apply a translation rule identified by a dialplan id and an input string.

Name: dialplan.translate

Parameters: 2

- Dial plan ID (number)

- Input string (string) - it can be prefixed with 's:' to avoid auto-conversion when the command is executed with CLI apps such as &kamctl;.

Example:

    		&kamctl; rpc dialplan.translate 1 "abcdxyz"
    		&kamctl; rpc dialplan.translate 1 s:123456789

## Installation

This module requires one table in &kamailio; database: dialplan. The SQL syntax to create them can be found in dialplan-create.sql script in the database directories in the kamailio/scripts folder. You can also find the complete database documentation on the project webpage, &kamailiodbdocslink;.

Some sample records from a dialplan table are presented in the next figure.

### Example of rules

    ...
    dpid: 1
    pr: 1
    match_op: 1
    match_exp: ^0[1-9][0-9]+$
    match_len: 0
    subst_exp: ^0([1-9][0-9]+)$
    repl_exp: 0049\1
    attrs: de
    ...
    dpid: 1
    pr: 2
    match_op: 1
    match_exp: ^0[1-9][0-9]+$
    match_len: 0
    subst_exp: ^0(.+)$
    repl_exp: $var(prefix)\1
    attrs: xyz
    ...

Note that you can use config variables in the replacement expression (repl_exp) field. However, not all of config variables are safe to use there - specifically the variables that have in their name other variables (variables with dynamic name). References to SIP message, private variables ($var(...)) and AVPs with static name are among those that are safe to use in replacement expressions.

The match_op field specify matching operator, valid values:

- 0 - string comparison;
- 1 - regular expression matching (pcre);
- 2 - fnmatch (shell-like pattern) matching.