Postgre.SQL module for MTA-SA

Description

Simple module for MTA that provides Postgre.SQL client API.
I accept any support regarding the module development. Feel free to make PRs and Issues.

Installation

Information about Installation provided on the Releases page.

Functions

pg_conn function

Syntax

userdata pg_conn(string connection)

Description

Attempts to make connection with your Postgre.SQL server.

Parameters

string connection - connection query string.
Might look like:

• postgresql://USER:PASSWORD@IP:PORT/dbname?connect_timeout=3
• hostaddr=IP port=5432 dbname=DBNAME user=USERNAME password=PASSWORD

Return value

If the connection attempt is successfull, the function returns connection handle.
On the failure, the function returns 2 values:

• false (bool)
• Error message (string)

Example of usage

local conn,err = pg_conn("postgresql://user:[email protected]:5432/mydb?connect_timeout=3");	
if (err ~= nil) then
   print(err)
   return 1;
end

pg_query function

Syntax

userdata pg_query(userdata connection, string query)

Description

Sends query to the Postgre.SQL server with provided data. String escaping supports as well.

Parameters

userdata connection - connection handle (see pg_conn).
string query - query to send to the Postgre.SQL server.

Return value

If query was sent successfully, the function returns userdata with the query result handle.
On the failure, the function returns 2 values:

• false (bool)
• Error message (string)

Example of usage

local query,qerr = pg_query(conn, "SELECT $1 as a, $2 as b", -67, 2)
if (query == false)  then
    iprint(qerr)
end	

pg_poll function

Syntax

table pg_poll(userdata query)	

Description

Gets the data from the query result handle.

Parameters

userdata query - query result handle (see pg_query).

Return value

On the success, the function returns a table.
On the failure, the function returns 1 value:

• false (bool)

Example of usage

local query,qerr = pg_query(conn, "SELECT $1 as a, $2 as b", -67, 2)
if (query == false)  then
    iprint(qerr)
end
iprint(pg_poll(query));

pg_free function

Syntax

bool pg_free(userdata query)

Description

Frees memory after executing the query (in case it didn't happen before).

Parameters

userdata query - query result handle (see pg_query).

Return value

If the query result handle is valid, the function returns true (bool).
Otherwise the function returns false (bool).

Example of usage

local query,qerr = pg_query(conn, "SELECT $1 as a, $2 as b", -67, 2)
pg_free(query)

pg_exec function

Syntax

bool pg_exec(userdata connection, string query)

Description

Sends query to the Postgre.SQL server, except it doesn't return any data like pg_query.

Parameters

userdata connection - connection handle (see pg_conn).
string query - query to send to the Postgre.SQL server.

Return value

If query was successfully sent, the function returns userdata with the query result handle.
On the failure, the function returns 2 values:

• false (bool)
• Error message (string)

Example of usage

local exec = pg_exec(conn, "INSERT INTO users (name, password, money) VALUES ($1,$2,$3)", "a man", "mypasswd", "13");
iprint(exec);

pg_close function

Syntax

bool pg_close(userdata connection)

Description

Closes connection with the Posgre.SQL server.

Parameters

userdata connection - connection handle (see pg_conn).

Return value

If connection was closed successfully, the function returns true (bool).
On the failure, the function returns false (bool).

Example of usage

local conn,err = pg_conn("postgresql://user:[email protected]:5432/mydb?connect_timeout=3");

... (some code here)

pg_close(conn);