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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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By default Recital uses PAM to authenticate users.  It is also possible to tell PAM to use Kerberos.  Simply replace the existing entries in the /etc/pam.d/recital file with the ones below:

auth       sufficient   pam_krb5.so try_first_pass
auth       sufficient   pam_unix.so shadow nullok try_first_pass
account    required     pam_unix.so broken_shadow
account    [default=bad success=ok user_unknown=ignore] pam_krb5.so
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In this article Barry Mavin, CEO and Chief Software Architect for Recital provides details on how to use the Recital Universal .NET Data Provider with the Recital Database Server.

Overview

A data provider in the .NET Framework serves as a bridge between an application and a data source. A data provider is used to retrieve data from a data source and to reconcile changes to that data back to the data source.

Each .NET Framework data provider has a DataAdapter object: the .NET Framework Data Provider for OLE DB is the OleDbDataAdapter object, the .NET Framework Data Provider for SQL Server is the SqlDataAdapter object, the .NET Framework Data Provider for ODBC is the OdbcDataAdapter object, and the .NET Framework Data Provider for the Recital Database Server is the RecitalDataAdapter object.

The Recital Universal .NET Data Provider can access any data sources supported by the Recital Database Server. It is not restricted to only access Recital data. It can be used to access server-side ODBC, JDBC and OLE DB data sources also.

Core classes of the Data Provider

The Connection, Command, DataReader, and DataAdapter objects represent the core elements of the .NET Framework data provider model. The Recital Universal .NET Data Provider is plug compatible with the .NET Framework Data Provider for SQL Server. All SQL Server classes are prefixed with "Sql" e.g. SqlDataAdaptor. To use the Recital Universal Data Adaptor, simply change the "Sql" prefix to "Recital" e.g. RecitalDataAdaptor.

The following table describes these objects.

Object Description
RecitalConnection Establishes a connection to a specific data source.
RecitalCommand Executes a command against a data source.
RecitalDataReader Reads a forward-only, read-only stream of data from a data source.
RecitalDataAdapter Populates a DataSet and resolves updates with the data source.

Along with the core classes listed in the preceding table, a .NET Framework data provider also contains the classes listed in the following table.


Object Description
RecitalTransaction Enables you to enlist commands in transactions at the data source.
RecitalCommandBuilder A helper object that will automatically generate command properties of a DataAdapter or will derive parameter information from a stored procedure and populate the Parameters collection of a Command object.
RecitalParameter Defines input, output, and return value parameters for commands and stored procedures.

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 .NET Data Provider supports a connection string format that is similar to the SQL Server connection string format.

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 within the ConnectionString property of the RecitalConnection class.


Name Default Description
Data Source
-or-
Server
-or-
Servername
-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
-or-
uid
-or-
User
-or-
Username
  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


Populating a DataSet from a DataAdaptor

The ADO.NET DataSet is a memory-resident representation of data that provides a consistent relational programming model independent of the data source. The DataSet represents a complete set of data including tables, constraints, and relationships among the tables. Because the DataSet is independent of the data source, a DataSet can include data local to the application, as well as data from multiple data sources. Interaction with existing data sources is controlled through the DataAdapter.

A DataAdapter is used to retrieve data from a data source and populate tables within a DataSet. The DataAdapter also resolves changes made to the DataSet back to the data source. The DataAdapter uses the Connection object of the .NET Framework data provider to connect to a data source and Command objects to retrieve data from and resolve changes to the data source.

The SelectCommand property of the DataAdapter is a Command object that retrieves data from the data source. The InsertCommand, UpdateCommand, and DeleteCommand properties of the DataAdapter are Command objects that manage updates to the data in the data source according to modifications made to the data in the DataSet.

The Fill method of the DataAdapter is used to populate a DataSet with the results of the SelectCommand of the DataAdapter. Fill takes as its arguments a DataSet to be populated, and a DataTable object, or the name of the DataTable to be filled with the rows returned from the SelectCommand.

The Fill method uses the DataReader object implicitly to return the column names and types used to create the tables in the DataSet, as well as the data to populate the rows of the tables in the DataSet. Tables and columns are only created if they do not already exist; otherwise Fill uses the existing DataSet schema.

Examples in C#:
////////////////////////////////////////////////////////////////////////
// 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 Southwind database 
// and 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()
{
	RecitalConnection swindConn = new
		RecitalConnection("Data Source=localhost;Initial Catalog=southwind");
	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;
}

////////////////////////////////////////////////////////////////////////
// The following example uses the RecitalCommand, RecitalDataAdapter and 
// RecitalConnection, to select records from a database, and populate a 
// DataSet with the selected rows. The filled DataSet is then returned. 
// To accomplish this, the method is passed an initialized DataSet, a 
// connection string, and a query string that is a SQL SELECT statement
public DataSet SelectRecitalRows(DataSet dataset, string connection, string query) 
{
	RecitalConnection conn = new RecitalConnection(connection);
	SqlDataAdapter adapter = new RecitalDataAdapter();
	adapter.SelectCommand = new RecitalCommand(query, conn);
	adapter.Fill(dataset);
	return dataset;
}
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Add this directive to your /etc/httpd/httpd.conf file and restart apache.
DirectoryIndex default.rsp index.html 
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This guide will assist you in setting up an rsnapshot backup server on your network. rsnapshot uses rsync via ssh to perform unattended backups of multiple systems in your network. The guide can be found on the centos website here.

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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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In this article Barry Mavin, CEO and Chief Software Architect for Recital debunks the myths and misrepresentations surrounding XBase and explains how Recital, an enterprise-class XBase platform, has overcome all the shortfalls and weaknesses of early XBase implementations.

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A quick tip for optimizing TCP performance on linux.

edit /etc/sysctl.conf add the lines:

If using gigabit ethernet:

net.ipv4.tcp_mem= 98304 131072 196608
net.ipv4.tcp_window_scaling=1
net.core.wmem_default = 65536
net.core.rmem_default = 65536
net.core.wmem_max=8388608

To reload these use:

# sysctl -p

If using infiniband:

net.ipv4.tcp_window_scaling=1
net.ipv4.tcp_timestamps=0
net.ipv4.tcp_sack=0
net.ipv4.tcp_rmem=10000000 10000000 10000000
net.ipv4.tcp_wmem=10000000 10000000 10000000
net.ipv4.tcp_mem=10000000 10000000 10000000
net.core.rmem_max=524287
net.core.wmem_max=524287
net.core.rmem_default=524287
net.core.wmem_default=524287
net.core.optmem_max=524287
net.core.netdev_max_backlog=300000

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This website runs in a  virtual machine under vmware server. It is clustered between two servers using heartbeat and DRBD.
 
When VMware server starts up a virtual machine it generates a uuid (unique id) based on the machine it is running on and stores this in the .vmx file.
 
When heartbeat switches from slave to master, it will start VMware server (which is setup as a resource in the haresources file).
 
Virtual machines that you want started automatically when you start VMware server will not start because the uuid changes between the master and backup systems. To get around this problem always do the following:
  • edit the .vmx file and add the following line

    uuid.action = "keep"
If this is not done then everytime you try to run the virtual machine on the backup system in your cluster, VMware server will complain that the virtual machine has been copied or moved and it will not start it.
  • set the virtual machine to power off when vmware is stopped. Do not set this to "suspend" or it will not restart on the backup machine.
This will allow the virtual machine to start properly on the backup machine.
 
 
 
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SE Linux is a feature of the Linux kernel that provides mandatory access control. This policy based access control system grants far greater control over the resources on a machine than standard Linux access controls such as permissions.

Many modern Linux distributions are shipping with SELinux enabled by default, Fedora 14 and Rhel 6 both install with it enabled.

When you run Recital Web on a SELinux enabled machine and navigate to the default.rsp page you will see something similar to the screen shot below.

1
If you launch the SELinux troubleshooter you will see the following problem.

SELinux is blocking the apache server from accessing the Recital server running on port 8001.

2
To manage you SELinux policy you must have the policycoreutils package group installed. The policycoreutils contains the policy core utilities that are required for basic operation of a SELinux system.

If you wish to use a GUI tool, you must install the policycoreutils-gui package.

At the command prompt execute the following:

As root

$ yum install policycoreutils

$ semanage port -a -t http_port_t -p tcp 8001

$ service recital restart

$ service httpd restart 
 

We use the semanage command here to allow the http server access to port 8001. Once you have completed the steps detailed above you can go and navigate back to the default.rsp page in your borwser, where you will find the permission denied message is now replaced by the default.rsp page.


4
SELinux does a great job of restricting services and daemons so rather than simply disabling it, why not work with it!

When it comes to security, every little bit helps...

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