DBTEXT Module

Daniel-Constantin Mierla

   voice-system.ro

Edited by

Daniel-Constantin Mierla

   Copyright  2003, 2004 FhG FOKUS
     _________________________________________________________

   Table of Contents
   1. User's Guide

        1.1. Overview

              1.1.1. Design of dbtext engine
              1.1.2. Internal format of a dbtext table

        1.2. Dependencies

              1.2.1. OpenSER modules
              1.2.2. External libraries or applications

        1.3. Exported Parameters
        1.4. Exported Functions
        1.5. Installation & Running

              1.5.1. Using dbtext with basic OpenSER
                      configuration

   2. Developer's Guide
   3. Frequently Asked Questions

   List of Examples
   1-1. Sample of a dbtext table
   1-2. Minimal OpenSER location dbtext table definition
   1-3. Minimal OpenSER subscriber dbtext table example
   1-4. Load the dbtext module
   1-5. Definition of 'subscriber' table (one line)
   1-6. Definition of 'location' and 'aliases' tables (one line)
   1-7. Definition of 'version' table and sample records
   1-8. Configuration file
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Chapter 1. User's Guide

1.1. Overview

   The module implements a simplified database engine based on
   text files. It can be used by OpenSER DB interface instead of
   other database module (like MySQL).

   The module is meant for use in demos or small devices that do
   not support other DB modules. It keeps everything in memory
   and if you deal with large amount of data you may run quickly
   out of memory. Also, it has not implemented all standard
   database facilities (like order by), it includes minimal
   functionality to work properly (who knows ?!?) with OpenSER.
     _________________________________________________________

1.1.1. Design of dbtext engine

   The dbtext database system architecture:

     * a database is represented by a directory in the local file
       system. NOTE: when you use dbtext in OpenSER, the database
       URL for modules must be the path to the directory where
       the table-files are located, prefixed by "dbtext://",
       e.g., "dbtext:///var/dbtext/ser". If there is no "/" after
       "dbtext://" then "CFG_DIR/" is inserted at the beginning
       of the database path. So, either you provide an absolute
       path to database directory or a relative one to "CFG_DIR"
       directory.
     * a table is represented by a text file inside database
       directory.
     _________________________________________________________

1.1.2. Internal format of a dbtext table

   First line is the definition of the columns. Each column must
   be declared as follows:

     * the name of column must not include white spaces.
     * the format of a column definition is: name(type,attr).
     * between two column definitions must be a white space,
       e.g., "first_name(str) last_name(str)".
     * the type of a column can be:
          + int - integer numbers.
          + double - real numbers with two decimals.
          + str - strings with maximum size of 4KB.
     * a column can have one of the attributes:
          + auto - only for 'int' columns, the maximum value in
            that column is incremented and stored in this field
            if it is not provided in queries.
          + null - accept null values in column fields.
          + if no attribute is set, the fields of the column
            cannot have null value.
     * each other line is a row with data. The line ends with
       "\n".
     * the fields are separated by ":".
     * no value between two ':' (or between ':' and start/end of
       a row) means "null" value.
     * next characters must be escaped in strings: "\n", "\r",
       "\t", ":".
     * 0 -- the zero value must be escaped too.

   Example 1-1. Sample of a dbtext table
...
id(int,auto) name(str) flag(double) desc(str,null)
1:nick:0.34:a\tgood\: friend
2:cole:-3.75:colleague
3:bob:2.50:
...

   Example 1-2. Minimal OpenSER location dbtext table definition
...
username(str) contact(str) expires(int) q(double) callid(str) cseq(int)
...

   Example 1-3. Minimal OpenSER subscriber dbtext table example
...
username(str) password(str) ha1(str) domain(str) ha1b(str)
suser:supasswd:xxx:alpha.org:xxx
...
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1.2. Dependencies

1.2.1. OpenSER modules

   The next modules must be loaded before this module:

     * none.
     _________________________________________________________

1.2.2. External libraries or applications

   The next libraries or applications must be installed before
   running OpenSER with this module:

     * none.
     _________________________________________________________

1.3. Exported Parameters

   None.
     _________________________________________________________

1.4. Exported Functions

   None.
     _________________________________________________________

1.5. Installation & Running

   Compile the module and load it instead of mysql or other DB
   modules.

   REMINDER: when you use dbtext in OpenSER, the database URL for
   modules must be the path to the directory where the
   table-files are located, prefixed by "dbtext://", e.g.,
   "dbtext:///var/dbtext/ser". If there is no "/" after
   "dbtext://" then "CFG_DIR/" is inserted at the beginning of
   the database path. So, either you provide an absolute path to
   database directory or a relative one to "CFG_DIR" directory.

   Example 1-4. Load the dbtext module
...
loadmodule "/path/to/ser/modules/dbtext.so"
...
modparam("module_name", "database_URL", "/path/to/dbtext/database")
...
     _________________________________________________________

1.5.1. Using dbtext with basic OpenSER configuration

   Here are the definitions for most important table as well as a
   basic configuration file to use dbtext with OpenSER. The table
   structures may change in time and you will have to adjust next
   examples. These are know to work with upcoming OpenSER v0.9.0

   You have to populate the table 'subscriber' by hand with user
   profiles in order to have authentication. To use with the
   given configuration file, the table files must be placed in
   the '/tmp/serdb' directory.

   Example 1-5. Definition of 'subscriber' table (one line)
...
username(str) domain(str) password(str) first_name(str) last_name(str)
phone(str) email_address(str) datetime_created(int) datetime_modified(i
nt) confirmation(str) flag(str) sendnotification(str) greeting(str) ha1
(str) ha1b(str) perms(str) allow_find(str) timezone(str,null) rpid(str,
null)
...

   Example 1-6. Definition of 'location' and 'aliases' tables
   (one line)
...
username(str) domain(str,null) contact(str,null) received(str) expires(
int,null) q(double,null) callid(str,null) cseq(int,null) last_modified(
str) flags(int) user_agent(str) socket(str)
...

   Example 1-7. Definition of 'version' table and sample records
...
table_name(str) table_version(int)
subscriber:3
location:6
aliases:6
...

   Example 1-8. Configuration file
...
#
# $Id: README,v 1.4 2006/07/10 13:51:45 bogdan_iancu Exp $
#
# simple quick-start config script with dbtext
#

# ----------- global configuration parameters ------------------------

#debug=9         # debug level (cmd line: -dddddddddd)
#fork=yes
#log_stderror=no        # (cmd line: -E)

check_via=no    # (cmd. line: -v)
dns=no          # (cmd. line: -r)
rev_dns=no      # (cmd. line: -R)
children=4

listen=10.100.100.1
port=5060

fifo="/tmp/openser_fifo"

alias=alpha.org

# ------------------ module loading ----------------------------------

# use dbtext database
loadmodule "modules/dbtext/dbtext.so"

loadmodule "modules/sl/sl.so"
loadmodule "modules/tm/tm.so"
loadmodule "modules/rr/rr.so"
loadmodule "modules/maxfwd/maxfwd.so"
loadmodule "modules/usrloc/usrloc.so"
loadmodule "modules/registrar/registrar.so"
loadmodule "modules/textops/textops.so"

# modules for digest authentication
loadmodule "modules/auth/auth.so"
loadmodule "modules/auth_db/auth_db.so"

# ----------------- setting module-specific parameters ---------------

# -- usrloc params --

# use dbtext database for persistent storage
modparam("usrloc", "db_mode", 2)
modparam("usrloc|auth_db", "db_url", "dbtext:///tmp/openserdb")

# -- auth params --
#
modparam("auth_db", "calculate_ha1", 1)
modparam("auth_db", "password_column", "password")
modparam("auth_db", "user_column", "username")
modparam("auth_db", "domain_column", "domain")

# -- rr params --
# add value to ;lr param to make some broken UAs happy
modparam("rr", "enable_full_lr", 1)

# -------------------------  request routing logic -------------------

# main routing logic

route{
    # initial sanity checks -- messages with
    # max_forwards==0, or excessively long requests
    if (!mf_process_maxfwd_header("10")) {
        sl_send_reply("483","Too Many Hops");
        break;
    };
    if (msg:len >=  max_len ) {
        sl_send_reply("513", "Message too big");
        break;
    };

    # we record-route all messages -- to make sure that
    # subsequent messages will go through our proxy; that's
    # particularly good if upstream and downstream entities
    # use different transport protocol
    if (!method=="REGISTER") record_route();

    # subsequent messages withing a dialog should take the
    # path determined by record-routing
    if (loose_route()) {
        # mark routing logic in request
        append_hf("P-hint: rr-enforced\r\n");
        route(1);
        break;
    };

    if (!uri==myself) {
        # mark routing logic in request
        append_hf("P-hint: outbound\r\n");
        route(1);
        break;
    };

    # if the request is for other domain use UsrLoc
    # (in case, it does not work, use the following command
    # with proper names and addresses in it)
    if (uri==myself) {
        if (method=="REGISTER") {
            # digest authentication
            if (!www_authorize("", "subscriber")) {
                www_challenge("", "0");
                break;
            };

            save("location");
            break;
        };

        lookup("aliases");
        if (!uri==myself) {
            append_hf("P-hint: outbound alias\r\n");
            route(1);
            break;
        };

        # native SIP destinations are handled using our USRLOC DB
        if (!lookup("location")) {
            sl_send_reply("404", "Not Found");
            break;
        };
    };
    append_hf("P-hint: usrloc applied\r\n");
    route(1);
}

route[1]
{
    # send it out now; use stateful forwarding as it works reliably
    # even for UDP2TCP
    if (!t_relay()) {
        sl_reply_error();
    };
}


...
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Chapter 2. Developer's Guide

   Once you have the module loaded, you can use the API specified
   by OpenSER DB interface.
     _________________________________________________________

Chapter 3. Frequently Asked Questions

   3.1. Where can I find more about OpenSER?
   3.2. Where can I post a question about this module?
   3.3. How can I report a bug?

   3.1. Where can I find more about OpenSER?

   Take a look at http://openser.org/.

   3.2. Where can I post a question about this module?

   First at all check if your question was already answered on
   one of our mailing lists:

     * User Mailing List -
       http://openser.org/cgi-bin/mailman/listinfo/users
     * Developer Mailing List -
       http://openser.org/cgi-bin/mailman/listinfo/devel

   E-mails regarding any stable OpenSER release should be sent to
   <users@openser.org> and e-mails regarding development versions
   should be sent to <devel@openser.org>.

   If you want to keep the mail private, send it to
   <team@openser.org>.

   3.3. How can I report a bug?

   Please follow the guidelines provided at:
   http://sourceforge.net/tracker/?group_id=139143.