HOWTO: Restrict ssh access by IP Address and/or username

Opening SSH to the outside world is a security risk. Here is how to restrict SSH access to certain IP addresses on a machine.

Edit the /etc/hosts.allow file to include these lines, assuming your machine is on the 192.168.2.x nonrouting IP block, and you want to enable an external address of 217.40.111.121 IP block: Remember to add the period on the end of each incomplete IP number. If you have another complete IP address or range, add a space and that range on the end.
```
sshd,sshdfwd-X11: 192.168.2. 217.40.111.121
```
Edit your /etc/hosts.deny file to include this line:
```
sshd,sshdfwd-X11:ALL 
```
These lines refuse SSH connections from anyone not in the IP address blocks listed.

Additionally you can restrict SSH access by username.

Edit the /etc/ssh/sshd_config file and add the following lines

PermitRootLogin no
AllowUsers      user1 user2 user3 etc
PasswordAuthentication yes

Now restart the ssh daemon for these changes to take effect

service sshd restart

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HOWTO: Using more than 4GB of memory on centos 5.3

If you have 4 GB or more RAM use the Linux kernel compiled for PAE capable machines. Your machine may not show up total 4GB ram. All you have to do is install PAE kernel package.

This package includes a version of the Linux kernel with support for up to 64GB of high memory. It requires a CPU with Physical Address Extensions (PAE).

The non-PAE kernel can only address up to 4GB of memory. Install the kernel-PAE package if your machine has more than 4GB of memory (>=4GB).

# yum install kernel-PAE

If you want to know how much memory centos is using type this in a terminal:

# cat /proc/meminfo

Published in Blogs

Building C Extension Libraries

In this article Barry Mavin, CEO and Chief Software Architect for Recital details how to Build C Extension Libraries to use with Recital.

Overview

It is possible to extend the functionaliy of Recital products using "Extension libraries" that can be written in C. These extension libraries, written using the Recital/SDK API, are dynamically loadable from all Recital 9 products. This includes:

Recital
Recital Server
Recital Web

Building C Extension Libraries

You can create C wrappers for virtually any native operating system function and access these from the Recital 4GL. Unlike traditional APIs which only handle the development of C functions that are callable from the 4GL, the Recital/SDK allows you to build Classes that are accessible from all Recital products. e.g. You could create a GUI framework for Linux that handles VFP system classes!

To deploy your C Extension Libraries, copy them to the following location:

Windows:

\Program Files\Recital\extensions

Linux/Unix:

/opt/recital/extensions

Please see the Recital/SDK API Reference documentation for further details.

Sample code

Listed below is the complete example of a C Extension Library.:

////////////////////////////////////////////////////////////////////////////////
#include "mirage_demo.h"  
      
////////////////////////////////////////////////////////////////////////////////
// Declare your functions and classes below as follows:
//
//    Recital Function Name, C Function Name, Type (Function or Class)
//
#define MAX_ELEMENTS    7
static  struct  API_SHARED_FUNCTION_TABLE api_function_table[MAX_ELEMENTS] = {
        {"schar",   "fnSamplesCharacter",   API_FUNCTION},
        {"stype",   "fnSamplesType",           API_FUNCTION},
        {"slog",    "fnSamplesLogical",        API_FUNCTION},
        {"snum",    "fnSamplesNumeric",    API_FUNCTION},
        {"sopen",   "fnSamplesOpen",         API_FUNCTION},
        {"myclass", "clsMyClass",               API_CLASS},
        {NULL,      NULL,                   -1}
};

////////////////////////////////////////////////////////////////////////////////
// Recital API initialization. This should be in only ONE of your C files
// **IT SHOULD NEVER BE EDITED OR REMOVED**  
INIT_API;


///////////////////////////////////////////////////////////////////////
// This is an example of passing a character parameter and returning one.
RECITAL_FUNCTION fnSamplesCharacter(void)
{
    char    *arg1;
    
    if (!_parse_parameters(PCOUNT, "C", &arg1)) { 
        ERROR(-1, "Incorrect parameters");
    }
    
    _retc(arg1);
}


///////////////////////////////////////////////////////////////////////
// This is an example of passing a numeric parameter and returning one.
RECITAL_FUNCTION fnSamplesNumeric(void)
{
    int arg1;
    
    if (!_parse_parameters(PCOUNT, "N", &arg1)) { 
        ERROR(-1, "Incorrect parameters");
    }
    
    _retni(arg1);
}


///////////////////////////////////////////////////////////////////////
// This is an example returns the data type of the parameter passed.
RECITAL_FUNCTION fnSamplesType(void)
{
    char    result[10];

    if (PCOUNT != 1) { 
        ERROR(-1, "Incorrect parameters");
    }
    
    switch (_parinfo(1)) {
        case API_CTYPE:
            strcpy(result, "Character");
            break;
        case API_NTYPE:
            strcpy(result, "Numeric");
            break;
        case API_LTYPE:
            strcpy(result, "Logical");
            break;
        case API_DTYPE:
            strcpy(result, "Date");
            break;
        case API_TTYPE:
            strcpy(result, "DateTime");
            break;
        case API_YTYPE:
            strcpy(result, "Currency");
            break;
        case API_ATYPE:
            strcpy(result, "Array");
            break;
        default:
            strcpy(result, "Unkown");
            break;
    }

    _retc(result);
}


///////////////////////////////////////////////////////////////////////
// This is an example returns "True" or False.
RECITAL_FUNCTION  fnSamplesLogical(void)
{
    char    result[10];
    int     arg1;
    
    if (!_parse_parameters(PCOUNT, "L", &arg1)) { 
        ERROR(-1, "Incorrect parameters");
    }
    
    if (arg1) strcpy(result, "True");
    else strcpy(result, "False");

    _retc(result);
}


///////////////////////////////////////////////////////////////////////
// This example opens a table.
RECITAL_FUNCTION fnSamplesOpen(void)
{
    char    *arg1;
    
    if (!_parse_parameters(PCOUNT, "C", &arg1)) { 
        ERROR(-1, "Incorrect parameters");
    }
    
    if (_parinfo(1) == API_CTYPE) {
        _retni(COMMAND(arg1));
    } else {
        _retni(-1);
    }
}

///////////////////////////////////////////////////////////////////////
// Define the MyClass CLASS using the API macros
///////////////////////////////////////////////////////////////////////
RECITAL_EXPORT int DEFINE_CLASS(clsMyClass)
{
    /*-------------------------------------*/ 
    /* Dispatch factory methods and return */
    /*-------------------------------------*/
    DISPATCH_FACTORY();
 
    /*---------------------------------*/
    /* Dispatch constructor and return */ 
    /*---------------------------------*/ 
    DISPATCH_METHOD(clsMyClass, Constructor);

    /*--------------------------------*/
    /* Dispatch destructor and return */
    /*--------------------------------*/
    DISPATCH_METHOD(clsMyClass, Destructor); 

    /*-----------------------------------*/
    /* Dispatch DEFINE method and return */
    /*-----------------------------------*/
    DISPATCH_METHOD(clsMyClass, Define);

    /*------------------------------*/
    /* Dispatch SET or GET PROPERTY */
    /* method for property NumValue */
    /* then return.                 */
    /*------------------------------*/
    DISPATCH_PROPSET(clsMyClass, NumValue);
    DISPATCH_PROPGET(clsMyClass, NumValue); 

    /*------------------------------*/
    /* Dispatch SET or GET PROPERTY */
    /* method for property LogValue */
    /* then return.                 */
    /*------------------------------*/
    DISPATCH_PROPSET(clsMyClass, LogValue);
    DISPATCH_PROPGET(clsMyClass, LogValue);

    /*-------------------------------*/
    /* Dispatch SET or GET PROPERTY  */
    /* method for property DateValue */
    /* then return.                 */
    /*-------------------------------*/
    DISPATCH_PROPSET(clsMyClass, DateValue);
    DISPATCH_PROPGET(clsMyClass, DateValue);

    /*-------------------------------*/
    /* Dispatch SET or GET PROPERTY  */
    /* method for property TimeValue */
    /* then return.                  */
    /*-------------------------------*/
    DISPATCH_PROPSET(clsMyClass, TimeValue);
    DISPATCH_PROPGET(clsMyClass, TimeValue);
 
    /*-------------------------------*/
    /* Dispatch SET or GET PROPERTY  */
    /* method for property CurrValue */
    /* then return.                  */
    /*-------------------------------*/
    DISPATCH_PROPSET(clsMyClass, CurrValue);
    DISPATCH_PROPGET(clsMyClass, CurrValue);

    /*-------------------------------*/
    /* Dispatch SET or GET PROPERTY  */
    /* method for property CharValue */
    /* then return.                  */
    /*-------------------------------*/
    DISPATCH_PROPSET(clsMyClass, CharValue); 
    DISPATCH_PROPGET(clsMyClass, CharValue);

    /*------------------------------*/
    /* Dispatch SET or GET PROPERTY */ 
    /* method for property ObjValue */ 
    /* then return.                 */
    /*------------------------------*/
    DISPATCH_PROPSET(clsMyClass, ObjValue);
    DISPATCH_PROPGET(clsMyClass, ObjValue);

    /*-----------------------------------*/
    /* If message not found return error */
    /*-----------------------------------*/
    OBJECT_RETERROR("Unknown message type");
}

////////////////////////////////////////////////////////////////////////////////
// Define METHOD handlers
////////////////////////////////////////////////////////////////////////////////
DEFINE_METHOD(clsMyClass, Constructor) 
{
        struct example_data *objectDataArea;

        /* Allocate memory for objects objectData area */
        objectDataArea = (struct example_data *) 
           malloc(sizeof(struct example_data));
        if (objectDataArea == NULL) return(-1);
    
        /* Assign the default property values */
        strcpy(objectDataArea->prop_charvalue, "Test API object");
        objectDataArea->prop_numvalue = 15.2827;
        objectDataArea->prop_logvalue = 'F';
        strcpy(objectDataArea->prop_datevalue, DATE_DATE());
        strcpy(objectDataArea->prop_timevalue, DATE_DATETIME());
        strcpy(objectDataArea->prop_currvalue, "15.2827");
        strcpy(objectDataArea->object_name, "APIobject");
        objectDataArea->prop_objvalue 
             = OBJECT_NEW(objectDataArea->object_name, "exception", NULL);
    
        /* Set the object objectData area */
        OBJECT_SETDATA((char *)objectDataArea);
    
        return(0);
}
  
DEFINE_METHOD(clsMyClass, Destructor) 
{
        struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();

        if (objectData != NULL) {
            if (objectData->prop_objvalue != NULL) 
              OBJECT_DELETE(objectData->prop_objvalue);
            free(objectData);
            objectData = NULL;
        }
        return(0);
}

DEFINE_METHOD(clsMyClass, Define) 
{
    struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
    struct      API_EXPRESSION result;
    char        buffer[512];
    int         rc;

/* Check the object class */
    OBJECT_GETPROPERTY(objectData->prop_objvalue, "class", buffer);
    rc = OBJECT_GETARG(buffer, &result);
    if (result.errno == 0 && result.type == 'C' 
        && strcmp(result.character, "Exception") == 0) { 
        switch (OBJECT_GETARGC()) {
            case 1: 
                rc = OBJECT_GETPARAMETER(1, &result);
                if (result.errno == 0 && result.type == 'C') {
                    OBJECT_SETARG(buffer, &result);
                    rc = OBJECT_SETPROPERTY(objectData->prop_objvalue,
                         "message", buffer);
                }
                break;
            case 2: 
                rc = OBJECT_GETPARAMETER(2, &result);
                if (result.errno == 0 && result.type == 'N') {
                    OBJECT_SETARG(buffer, &result);
                    rc = OBJECT_SETPROPERTY(objectData->prop_objvalue,
                         "errorno", buffer);
                }
         }
    }

    result.type = 'L';
    result.logical = (rc == 0 ? 'T' : 'F');  
    OBJECT_RETRESULT(&result);
}

////////////////////////////////////////////////////////////////////////////////
// Define GET property handlers
////////////////////////////////////////////////////////////////////////////////
DEFINE_PROPERTYGET(clsMyClass, NumValue) 
{
    struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();

    if (objectData == NULL) return(-1);

    OBJECT_RETPROPERTY('N', objectData->prop_numvalue);
}

DEFINE_PROPERTYGET(clsMyClass, LogValue) 
{
    struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();

    if (objectData == NULL) return(-1);

    OBJECT_RETPROPERTY('L', objectData->prop_logvalue);
}  

DEFINE_PROPERTYGET(clsMyClass, DateValue) 
{
    struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();

    if (objectData == NULL) return(-1);

    OBJECT_RETPROPERTY('D', objectData->prop_datevalue);
}

DEFINE_PROPERTYGET(clsMyClass, TimeValue) 
{
    struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();

    if (objectData == NULL) return(-1);

    OBJECT_RETPROPERTY('T', objectData->prop_timevalue);
}

DEFINE_PROPERTYGET(clsMyClass, CurrValue) 
{
    struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();

    if (objectData == NULL) return(-1);

    OBJECT_RETPROPERTY('Y', objectData->prop_currvalue);
}

DEFINE_PROPERTYGET(clsMyClass, CharValue) 
{
    struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();

    if (objectData == NULL) return(-1);

    OBJECT_RETPROPERTY('C', objectData->prop_charvalue);
}

DEFINE_PROPERTYGET(clsMyClass, ObjValue) 
{
    struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();

    if (objectData == NULL) return(-1);

    OBJECT_RETPROPERTY('O', objectData->prop_objvalue);
} 


////////////////////////////////////////////////////////////////////////////////
// Define SET property handlers
////////////////////////////////////////////////////////////////////////////////
DEFINE_PROPERTYSET(clsMyClass, NumValue) 
{
    struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
    struct API_EXPRESSION result;
    int rc = OBJECT_ERROR;

    OBJECT_GETVALUE(&result);
    if (result.errno == 0 && result.type == 'N') {
        objectData->prop_numvalue = result.number;
        rc = OBJECT_SUCCESS;
    }

    return(rc);
}

DEFINE_PROPERTYSET(clsMyClass, LogValue) 
{
    struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
    struct API_EXPRESSION result;
    int rc = OBJECT_ERROR;

    OBJECT_GETVALUE(&result);
    if (result.errno == 0 && result.type == 'L') {
        objectData->prop_logvalue = result.logical;
        rc = OBJECT_SUCCESS;
    }

    return(rc);
}

DEFINE_PROPERTYSET(clsMyClass, DateValue) 
{
    struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
    struct API_EXPRESSION result;
    int rc = OBJECT_ERROR;
    OBJECT_GETVALUE(&result);
    if (result.errno == 0 && result.type == 'D') {
        strcpy(objectData->prop_datevalue, DATE_DTOS(result.date));
        rc = OBJECT_SUCCESS;
    }

    return(rc);
}

DEFINE_PROPERTYSET(clsMyClass, TimeValue) 
{
    struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
    struct API_EXPRESSION result;
    int rc = OBJECT_ERROR;

    OBJECT_GETVALUE(&result);
    if (result.errno == 0 && result.type == 'T') {
        strcpy(objectData->prop_timevalue, DATE_TTOS(result.datetime));
        rc = OBJECT_SUCCESS;
    }

    return(rc); 
}

DEFINE_PROPERTYSET(clsMyClass, CurrValue) 
{
    struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
    struct API_EXPRESSION result;
    int rc = OBJECT_ERROR;

    OBJECT_GETVALUE(&result);
    if (result.errno == 0 && result.type == 'Y') {
        strcpy(objectData->prop_currvalue, CURR_YTOS(result.currency));
        rc = OBJECT_SUCCESS;
    }

    return(rc);
}

DEFINE_PROPERTYSET(clsMyClass, CharValue)  
{
    struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
    struct API_EXPRESSION result;
    int rc = OBJECT_ERROR;

    OBJECT_GETVALUE(&result);
    if (result.errno == 0 && result.type == 'C') {
        strcpy(objectData->prop_currvalue, result.character);
        rc = OBJECT_SUCCESS;
    }

    return(rc);
}

DEFINE_PROPERTYSET(clsMyClass, ObjValue) 
{
    struct example_data *objectData = (struct example_data *)OBJECT_GETDATA();
    OBJECT  objvalue;
    int rc = OBJECT_ERROR;

    if (OBJECT_GETTYPE() == 'O') {
        objvalue = OBJECT_GETOBJECT(); 
        objectData->prop_objvalue = OBJECT_ASSIGN(objvalue, objectData->object_name);
        rc = OBJECT_SUCCESS;
    }

    return(rc);
}

Published in Blogs

Finally IE9 will support rounded corners

And apparently IE9 will support rounded corners.
http://kbala.com/ie-9-supports-corner-radius/

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Openfiler open source storage appliance distro for use with Recital

The Openfiler NAS/SAN Appliance (NSA) is a Storage Management Operating System / NAS Appliance distribution. It is powered by the Linux 2.6 kernel and Open Source applications such as Apache, Samba, LVM2, ext3, Linux NFS and iSCSI Enterprise Target. Openfiler combines these ubiquitous technologies into a small, easy to manage solution fronted by a powerful web-based management interface. Openfiler allows you to build a Network Attached Storage (NAS) and/or Storage Area Network (SAN) appliance, using industry-standard hardware, in less than 10 minutes of installation time.

Building upon the popularity of server virtualization technologies such as VMware, Virtual Iron, and Xen, Openfiler can also be deployed as a virtual machine instance or on a bare metal machine.

This deployment flexibility of Openfiler ensures that storage administrators are able to make the best use of system performance and storage capacity resources when allocating and managing networked storage in a multi-platform environment.

Openfiler is ideally suited for use with High Availability Recital applications as it incorporates:

Heartbeat cluster manager
drbd disk replication
CIFS
NFS
Software and hardware RAID
FTP
rsync
HTTP/DAV
iSCSI
LVM2
Multiple NIC bonding for High Availability
Powerful web-based GUI

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HOWTO: Save a Flex Canvas as a jpg file on the server

The getUIComponentBitmapData method can create bitmapdata for a given IUIComponent. Pass any UIcomponent to get its respective bitmapdata.

public static function getUIComponentBitmapData(target:IUIComponent):BitmapData {      
    var resultBitmapData:BitmapData = new BitmapData(target.width, target.height);     
    var m:Matrix = new Matrix();     
    resultBitmapData.draw(target, m);     
    return resultBitmapData; 
}

Now convert the bitmapdata to a jpeg bytearray.

private static function encodeToJPEG(data:BitmapData, quality:Number = 75):ByteArray {     
    var encoder:JPGEncoder = new JPGEncoder(quality);     
    return encoder.encode(data); 
}

Now encode the ByteArray into Base64.

public static function base64Encode(data:ByteArray):String {     
    var encoder:Base64Encoder = new Base64Encoder();     
    encoder.encodeBytes(data);     
    return encoder.flush(); 
}

Upload the base64 encoded ByteArray to the server.

public static uploadData():void {     
    var url:String = "saveFile.php";     
    var urlRequest:URLRequest = new URLRequest(url);     
    urlRequest.method = URLRequestMethod.POST;     
    var urlLoader:URLLoader = new URLLoader();     
    var urlVariables:URLVariables = new URLVariables();     
    urlVariables.file = jpgEncodedFile;    // as returned from base64Encode()     
    urlLoader.data = urlVariables;     
    urlLoader.load(urlRequest); 
}

The saveFile.php file on the server.

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Tagged under

HOWTO
FLEX

FIX: ssh: Connection closed by remote host

When stress testing our loadbalancer, i was unable to get more than 20 reliable ssh connections. The following error would be reported.

ssh_exchange_identification: Connection closed by remote host

The resolution for this is quite simple.

Edit the /etc/ssh/sshd_config file and increase the MaxStartups. On my server i set this to 200.

Edit /etc/sysctrl.conf and add the following line:

net.core.netdev_max_backlog = 3000

Then apply this change:

# sysctl -p

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Working with server-side OLE DB data sources

In this article Barry Mavin, CEO and Chief Software Architect for Recital, details how to use the Client Drivers provided with the Recital Database Server to work with local or remote server-side OLE DB data sources.

Overview

The Recital Universal .NET Data Provider provides connectivity to the Recital Database Server running on any supported platform (Windows, Linux, Unix, OpenVMS) using the RecitalConnection object.

The Recital Universal JDBC Driver provides the same functionality for java applications.

The Recital Universal ODBC Driver provides the same functionality for applications that use ODBC.

Each of the above Client Drivers use a connection string to describe connections parameters.

The basic format of a connection string consists of a series of keyword/value pairs separated by semicolons. The equal sign (=) connects each keyword and its value.

The following table lists the valid names for keyword/values.

Name	Default	Description
Data Source -or- Server -or- Nodename		The name or network address of the instance of the Recital Database Server which to connect to.
Directory		The target directory on the remote server where data to be accessed resides. This is ignored when a Database is specified.
Encrypt -or- Encryption	false	When true, DES3 encryption is used for all data sent between the client and server.
Initial Catalog -or- Database		The name of the database on the remote server.
Password -or- Pwd		The password used to authenticate access to the remote server.
User ID		The user name used to authenticate access to the remote server.
Connection Pooling -or- Pool	false	Enable connection pooling to the server. This provides for one connection to be shared.
Logging	false	Provides for the ability to log all server requests for debugging purposes
Rowid	true	When Rowid is true (the default) a column will be post-fixed to each SELECT query that is a unique row identifier. This is used to provide optimised UPDATE and DELETE operations. If you use the RecitalSqlGrid, RecitalSqlForm, or RecitalSqlGridForm components then this column is not visible but is used to handle updates to the underlying data source.
Logfile		The name of the logfile for logging
Gateway		Opens an SQL gateway(Connection) to a foreign SQL data source on the remote server. Using Gateways, you can transparently access the following local or remote data sources: Recital Oracle ODBC (Server-side ODBC data sources) JDBC (Server-side JDBC data sources) ADO (Use this to connect to SQL Server and other Native Windows OLEDB data sources) MySQL PostgreSQL The gateway can be specified in several formats: servertype@nodename:username/password-database e.g. oracle@nodename:username/password-database mysql@nodename:username/password-database postgresql@nodename:username/password-database -or- odbc:odbc_data_source_name_on_server oledb:oledb_connection_string_on_server jdbc:jdbc_driver_path_on_server;jdbc:Recital:args

To connect to a server-side OLE DB data source, you use the gateway=value key/value pair in the following way.

gateway=oledb:oledb_connection_string_on_server

Important
When specifying the connection string be sure to quote the gateway= with "...".

You can find examples of connection strings for most ODBC and OLE DB data sources by clicking here.

Example in C# using the Recital Universal .NET Data Provider:

////////////////////////////////////////////////////////////////////////
// include the references below
using System.Data;
using Recital.Data;
 
////////////////////////////////////////////////////////////////////////
// The following code example creates an instance of a DataAdapter that 
// uses a Connection to the Recital Database Server, and a gateway to
// the SQL server Northwind database. It then populates a DataTable 
// in a DataSet with the list of customers. The SQL statement and 
// Connection arguments passed to the DataAdapter constructor are used 
// to create the SelectCommand property of the DataAdapter.
public DataSet SelectCustomers()
{
	string gateway = "oledb:Provider=sqloledb;Initial Catalog=Northwind;
		Data Source=localhost;Integrated Security=SSPI";
	RecitalConnection swindConn = new 
		RecitalConnection("Data Source=localhost;gateway=\""+gateway+"\");
	RecitalCommand selectCMD = new 
		RecitalCommand("SELECT CustomerID, CompanyName FROM Customers", swindConn);
	selectCMD.CommandTimeout = 30;
	RecitalDataAdapter custDA = new RecitalDataAdapter();
	custDA.SelectCommand = selectCMD;
	swindConn.Open();
	DataSet custDS = new DataSet();
	custDA.Fill(custDS, "Customers");
	swindConn.Close();
	return custDS;
}

Example in Java using the Recital Universal JDBC Driver:

////////////////////////////////////////////////////////////////////////
// standard imports required by the JDBC driver
import java.sql.*;
import java.io.*;
import java.net.URL;
import java.math.BigDecimal;
import Recital.sql.*;
 
////////////////////////////////////////////////////////////////////////
// The following code example creates a Connection to the Recital 
// Database Server, and a gateway to the SQL server Northwind database. 
// It then retrieves all the customers.
public void SelectCustomers()
{
    // setup the Connection URL for JDBC
	String gateway = "oledb:Provider=sqloledb;Initial Catalog=Northwind;
		Data Source=localhost;Integrated Security=SSPI";
	String url = "jdbc:Recital:Data Source=localhost;gateway=\""+gateway+"\";
	// load the Recital Universal JDBC Driver
	new RecitalDriver();
 
	// create the connection
	Connection con = DriverManager.getConnection(url);
	// create the statement
	Statement stmt = con.createStatement();
	// perform the SQL query
	ResultSet rs = stmt.executeQuery("SELECT CustomerID, CompanyName FROM Customers");
	// fetch the data
	while (rs.next()) 
	{
		String CompanyID = rs.getString("CustomerID");
		String CompanyName = rs.getString("CompanyName");
		// do something with the data...
	}
    
	// Release the statement
	stmt.close();
	
	// Disconnect from the server
	con.close();
}

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What is the best way to learn Recital?

The best way to learn Recital is to build some applications. The developers of Recital have written a book "Recital Essentials" which you can read here.

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Using anonymous classes in Recital

In Recital 10, you can declare anonymous classes and call anonymous methods in these classes.

// declare some simple procedures 
proc display(cArg)
    echo "display=" + cArg
endproc

proc show(cArg)
    echo "show=" + cArg
endproc

// create an object based on an anonymous class
myobj = new object()

// add some properties
myobj["name"] = "barry"
myobj["company"] = "recital"

// now declare an anonymous method
myobj["mymethod"] = display

// call the method
myobj.mymethod("hello world")    // displays "display=hello world"

// redeclare the method
myobj["mymethod"] = show

// call the method
myobj.mymethod("hello world")    // displays "show=hello world"

Where this becomes particularly useful is when you have a procedure that calls anonymous methods in order to process data. This technique can be used to call anonymous procedures in your code.

proc processdata(oArg)
    oArg.mymethod(oArg.name)    
endproc

proc show(cArg)
    echo "show=" + cArg
endproc

myobj = new object()
myobj["name"] = "barry"
myobj["mymethod"] = show
processdata(myobj)        // displays "show=barry"

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HOWTO: Restrict ssh access by IP Address and/or username

HOWTO: Using more than 4GB of memory on centos 5.3

Building C Extension Libraries

Overview

Building C Extension Libraries

Sample code

Finally IE9 will support rounded corners

Openfiler open source storage appliance distro for use with Recital

HOWTO: Save a Flex Canvas as a jpg file on the server

FIX: ssh: Connection closed by remote host

Working with server-side OLE DB data sources

Overview

Example in C# using the Recital Universal .NET Data Provider:

Example in Java using the Recital Universal JDBC Driver:

What is the best way to learn Recital?

Using anonymous classes in Recital

More...

Using Databases

HOWTO: Setup an rsnapshot backup server

HOWTO: Configure apache to always access a Recital Web page in a directory if one exists

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