RSS Component

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The RSS Component is used to retrieve, parse, edit, and write RSS-syndicated content.

Syntax

TipwRSS

Remarks

The RSS Component supports both plaintext and Secure Sockets Layer/Transport Layer Security (SSL/TLS) connections. When connecting over Secure Sockets Layer/Transport Layer Security (SSL/TLS) the SSLServerAuthentication event allows you to check the server identity and other security attributes. The SSLStatus event provides information about the SSL handshake. Additional SSL-related settings are also supported through the Config method.

The RSS Component implements a standard RSS newsreader with extended capabilities as specified at http://backend.userland.com/rss2.

The component contains a number of properties that map directly to RSS fields. To receive a feed, call the GetFeed method with the URL or file to retrieve as specified in the URL parameter. The RSS component also can generate RSS feeds, which can be retrieved through the RSSData property or written through the WriteFile method.

The RSS Component supports all RSS feed properties that are standard in versions 0.91, 0.92, and 2.0 of the RSS protocol through a number of component properties. It also supports nonstandard properties as specified in the RSS protocol through the Namespaces properties and the GetProperty and SetProperty methods.

Property List

The following is the full list of the properties of the component with short descriptions. Click on the links for further details.

Method List

The following is the full list of the methods of the component with short descriptions. Click on the links for further details.

Event List

The following is the full list of the events fired by the component with short descriptions. Click on the links for further details.

Config Settings

The following is a list of config settings for the component with short descriptions. Click on the links for further details.

Accept Property (RSS Component)

This property includes a list of acceptable MIME types for the request.

Syntax

property Accept: String read get_Accept write set_Accept;

Default Value

''

Remarks

If this property contains a nonempty string, an HTTP Accept header is added to the request.

The Accept header is used for content negotiation. It provides the server with a comma-separated list of MIME types that are acceptable for its response.

Authorization Property (RSS Component)

This property includes the Authorization string to be sent to the server.

Syntax

property Authorization: String read get_Authorization write set_Authorization;

Default Value

''

Remarks

If the Authorization property contains a nonempty string, an Authorization HTTP request header is added to the request. This header conveys Authorization information to the server.

A common use for this property is to specify OAuth authorization string.

This property is provided so that the HTTP component can be extended with other security schemes in addition to the authorization schemes already implemented by the component.

The AuthScheme property defines the authentication scheme used. In the case of HTTP Basic Authentication (default), every time User and Password are set, they are Base64 encoded, and the result is put in the Authorization property in the form 'Basic [encoded-user-password]'.

AuthScheme Property (RSS Component)

This property specifies the authentication scheme to use when server authentication is required.

Syntax

property AuthScheme: TipwTHTTPAuthSchemes read get_AuthScheme write set_AuthScheme;

TipwTHTTPAuthSchemes = (
  authBasic,
  authDigest,
  authProprietary,
  authNone,
  authNtlm,
  authNegotiate,
  authOAuth
);

Default Value

authBasic

Remarks

This property will tell the component which type of authorization to perform when the User and Password properties are set.

This property should be set to authNone (3) when no authentication is to be performed.

By default, this property is authBasic (0), and if the User and Password properties are set, the component will attempt HTTP Basic Authentication. If AuthScheme is set to authDigest (1), authNtlm (4), or authNegotiate (5), then Digest, NTLM, or Windows Negotiate (Kerberos) authentication will be attempted instead.

If AuthScheme is set to authProprietary (2), then the authorization token must be supplied through the Authorization property.

If AuthScheme is set to authOAuth (6), then the authorization string must be supplied through the Authorization property.

Note: If you set the Authorization property and AuthScheme is not authProprietary or authOAuth, then the AuthScheme will be set automatically to authProprietary (2) by the component.

For security, changing the value of this property will cause the component to clear the values of User, Password, and Authorization.

Channel Property (RSS Component)

This property includes the channel data for the feed.

Syntax

property Channel: TipwRSSChannel read get_Channel write set_Channel;

Remarks

This property contains fields that contain values for subelements of the RSS Channel.

Connected Property (RSS Component)

Whether the component is connected.

Syntax

property Connected: Boolean read get_Connected;

Default Value

false

Remarks

This property is used to determine whether or not the component is connected to the remote host. Use the Connect and Disconnect methods to manage the connection.

This property is read-only and not available at design time.

Cookies Property (RSS Component)

A collection of cookies.

Syntax

property Cookies: TipwHTTPCookieList read get_Cookies write set_Cookies;

Remarks

This property contains a collection of cookies. To add cookies to outgoing HTTP requests, add cookies (of type HTTPCookie) to this collection.

To see cookies that are set by the server, use the SetCookie event, which displays the cookies and their properties as set by the server. Those cookies also are added to Cookies.

MaxHTTPCookies can be used to control the maximum number of cookies saved.

This property is not available at design time.

Firewall Property (RSS Component)

A set of properties related to firewall access.

Syntax

property Firewall: TipwFirewall read get_Firewall write set_Firewall;

Remarks

This is a Firewall-type property, which contains fields describing the firewall through which the component will attempt to connect.

FollowRedirects Property (RSS Component)

Determines what happens when the server issues a redirect.

Syntax

property FollowRedirects: TipwTFollowRedirects read get_FollowRedirects write set_FollowRedirects;

TipwTFollowRedirects = (
  frNever,
  frAlways,
  frSameScheme
);

Default Value

frNever

Remarks

This property determines what happens when the server issues a redirect. Normally, the component returns an error if the server responds with an "Object Moved" message. If this property is set to frAlways (1), the new URL for the object is retrieved automatically every time.

If this property is set to frSameScheme (2), the new URL is retrieved automatically only if the URLScheme is the same; otherwise, the component raises an exception.

Note: Following the HTTP specification, unless this property is set to frAlways (1), automatic redirects will be performed only for GET or HEAD requests. Other methods potentially could change the conditions of the initial request and create security vulnerabilities.

Furthermore, if either the new URL server or port are different from the existing one, User and Password are also reset to empty. If, however, this property is set to frAlways (1), the same credentials are used to connect to the new server.

A Redirect event is fired for every URL the product is redirected to. In the case of automatic redirections, the Redirect event is a good place to set properties related to the new connection (e.g., new authentication parameters).

The default value is frNever (0). In this case, redirects are never followed, and the component raises an exception instead.

Idle Property (RSS Component)

The current status of the component.

Syntax

property Idle: Boolean read get_Idle;

Default Value

true

Remarks

This property will be False if the component is currently busy (communicating or waiting for an answer), and True at all other times.

This property is read-only.

IfModifiedSince Property (RSS Component)

This property includes a date determining the maximum age of the desired document.

Syntax

property IfModifiedSince: String read get_IfModifiedSince write set_IfModifiedSince;

Default Value

''

Remarks

If this property contains a nonempty string, an If-Modified-Since HTTP header is added to the request. The value of this header is used to make the HTTP request conditional: If the requested documented has not been modified since the time specified in the field, a copy of the document will not be returned from the server; instead, a 304 (not modified) response will be returned by the server and the component raises an exception

The format of the date value for IfModifiedSince is detailed in the HTTP specs. An example is Sat, 29 Oct 1994 19:43:31 GMT.

This property is not available at design time.

Items Property (RSS Component)

This property includes a collection of items in the current RSS feed.

Syntax

property Items: TipwRSSItemList read get_Items write set_Items;

Remarks

This property contains a collection of items in the current RSS channel. When an RSS feed is parsed by the component, all of the items in the feed are stored as RSSItem types in this collection.

This collection can also be populated before writing an RSS feed with WriteFile.

LocalFile Property (RSS Component)

This property includes the path to a local file for downloading. If the file exists, it is overwritten.

Syntax

property LocalFile: String read get_LocalFile write set_LocalFile;

Default Value

''

Remarks

This property is used when getting a document.

If this property is empty, then the received data are provided through TransferredData and the Transfer event.

LocalHost Property (RSS Component)

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

Syntax

property LocalHost: String read get_LocalHost write set_LocalHost;

Default Value

''

Remarks

This property contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multihomed hosts (machines with more than one IP interface) setting LocalHost to the IP address of an interface will make the component initiate connections (or accept in the case of server components) only through that interface. It is recommended to provide an IP address rather than a hostname when setting this property to ensure the desired interface is used.

If the component is connected, the LocalHost property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multihomed hosts (machines with more than one IP interface).

Note: LocalHost is not persistent. You must always set it in code, and never in the property window.

Namespaces Property (RSS Component)

This property includes a collection of namespaces in the current namespace stack.

Syntax

property Namespaces: TipwXMLNamespaceList read get_Namespaces write set_Namespaces;

Remarks

This property contains a list of the XML namespaces that exist in the current RSS channel. Each version of the RSS protocol defines a specific set of standard RSS feed properties. The general RSS protocol, however, allows nonstandard fields to be added through XML namespaces.

When parsing an RSS feed retrieved through the GetFeed method, the component will store all properties that are standard in version 2.0 of the RSS protocol, regardless of the version given by the feed. For nonstandard properties, it will verify that the property has a namespace and that the namespace is defined within the RSS feed. If a property's definition cannot be found, the component raises an exception. Nonstandard fields can be retrieved through the GetProperty method.

When using the WriteFile method to generate an RSS feed that contains nonstandard properties, you must use the SetProperty method to set each nonstandard property. The component will ignore any property whose namespace is not defined when generating the RSSData.

Please see the GetProperty and SetProperty methods for details on argument syntax.

This property is not available at design time.

OtherHeaders Property (RSS Component)

Other headers as determined by the user (optional).

Syntax

property OtherHeaders: String read get_OtherHeaders write set_OtherHeaders;

Default Value

''

Remarks

This property can be set to a string of headers to be appended to the HTTP request headers created from other properties like ContentType and From.

The headers must follow the format Header: Value as described in the HTTP specifications. Header lines should be separated by CRLF ('#13#10') .

Use this property with caution. If this property contains invalid headers, HTTP requests may fail.

This property is useful for extending the functionality of the component beyond what is provided.

This property is not available at design time.

ParsedHeaders Property (RSS Component)

This property includes a collection of headers returned from the last request.

Syntax

property ParsedHeaders: TipwHeaderList read get_ParsedHeaders;

Remarks

This property contains a collection of headers returned from the last request. Whenever headers are returned from the server, the headers are parsed into a collection of headers. Each Header in this collection contains information describing that header.

MaxHeaders can be used to control the maximum number of headers saved.

This property is read-only and not available at design time.

Password Property (RSS Component)

This property includes a password if authentication is to be used.

Syntax

property Password: String read get_Password write set_Password;

Default Value

''

Remarks

This property contains a password if authentication is to be used. If AuthScheme is set to HTTP Basic Authentication, the User and Password are Base64 encoded and the result is put in the Authorization configuration setting in the form 'Basic [encoded-user-password]'.

If AuthScheme is set to HTTP Digest Authentication, the User and Password properties are used to respond to the HTTP Digest Authentication challenge from the server.

If AuthScheme is set to NTLM, NTLM authentication will be attempted. If AuthScheme is set to NTLM and User and Password are empty, the component will attempt to authenticate using the current user's credentials.

Proxy Property (RSS Component)

A set of properties related to proxy access.

Syntax

property Proxy: TipwProxy read get_Proxy write set_Proxy;

Remarks

This property contains fields describing the proxy through which the component will attempt to connect.

Referer Property (RSS Component)

This property includes the referer URL/document (optional).

Syntax

property Referer: String read get_Referer write set_Referer;

Default Value

''

Remarks

If this property contains a nonempty string, a Referer HTTP request header is added to the request. The purpose of the header is to show the document referring the requested URL.

This property is not available at design time.

RSSData Property (RSS Component)

This property includes the complete text of the RSS XML file.

Syntax

property RSSData: String read get_RSSData write set_RSSData;

Default Value

''

Remarks

When retrieving RSS feeds through the GetFeed or HTML through the GetURL method, this property will contain the complete original text of the feed. When writing an RSS feed using the WriteFile method, the component RSSData will be generated from the existing properties.

This property is not available at design time.

RSSVersion Property (RSS Component)

This property includes the RSS protocol version of the current RSS feed.

Syntax

property RSSVersion: TipwTRSSVersions read get_RSSVersion write set_RSSVersion;

TipwTRSSVersions = (
  rssVersionUndefined,
  rssVersion091,
  rssVersion092,
  rssVersion200
);

Default Value

rssVersion200

Remarks

This property contains the protocol version to which the current RSS feed conforms. Each version has slightly different requirements and a different set of defined standard properties. When generating an RSS feed, the component will check this value and throw an error for missing required properties.

The following values are currently recognized by the component:

To set properties not defined in the given version, use the Namespaces properties, to list and define namespaces and the GetProperty and SetProperty methods, and to list and define each nonstandard property.

SSLAcceptServerCert Property (RSS Component)

Instructs the component to unconditionally accept the server certificate that matches the supplied certificate.

Syntax

property SSLAcceptServerCert: TipwCertificate read get_SSLAcceptServerCert write set_SSLAcceptServerCert;

Remarks

If it finds any issues with the certificate presented by the server, the component will normally terminate the connection with an error.

You may override this behavior by supplying a value for SSLAcceptServerCert. If the certificate supplied in SSLAcceptServerCert is the same as the certificate presented by the server, then the server certificate is accepted unconditionally, and the connection will continue normally.

Note: This functionality is provided only for cases in which you otherwise know that you are communicating with the right server. If used improperly, this property may create a security breach. Use it at your own risk.

SSLCert Property (RSS Component)

The certificate to be used during Secure Sockets Layer (SSL) negotiation.

Syntax

property SSLCert: TipwCertificate read get_SSLCert write set_SSLCert;

Remarks

This property includes the digital certificate that the component will use during SSL negotiation. Set this property to a valid certificate before starting SSL negotiation. To set a certificate, you may set the Encoded field to the encoded certificate. To select a certificate, use the store and subject fields.

SSLProvider Property (RSS Component)

The Secure Sockets Layer/Transport Layer Security (SSL/TLS) implementation to use.

Syntax

property SSLProvider: TipwTSSLProviders read get_SSLProvider write set_SSLProvider;

TipwTSSLProviders = (
  sslpAutomatic,
  sslpPlatform,
  sslpInternal
);

Default Value

sslpAutomatic

Remarks

This property specifies the SSL/TLS implementation to use. In most cases the default value of 0 (Automatic) is recommended and should not be changed. When set to 0 (Automatic), the component will select whether to use the platform implementation or the internal implementation depending on the operating system as well as the TLS version being used.

Possible values are as follows:

In most cases using the default value (Automatic) is recommended. The component will select a provider depending on the current platform.

When Automatic is selected, on Windows, the component will use the platform implementation. On Linux/macOS, the component will use the internal implementation. When TLS 1.3 is enabled via SSLEnabledProtocols, the internal implementation is used on all platforms.

SSLServerCert Property (RSS Component)

The server certificate for the last established connection.

Syntax

property SSLServerCert: TipwCertificate read get_SSLServerCert;

Remarks

This property contains the server certificate for the last established connection.

SSLServerCert is reset every time a new connection is attempted.

This property is read-only.

Timeout Property (RSS Component)

The timeout for the component.

Syntax

property Timeout: Integer read get_Timeout write set_Timeout;

Default Value

60

Remarks

If the Timeout property is set to 0, all operations will run uninterrupted until successful completion or an error condition is encountered.

If Timeout is set to a positive value, the component will wait for the operation to complete before returning control.

The component will use DoEvents to enter an efficient wait loop during any potential waiting period, making sure that all system events are processed immediately as they arrive. This ensures that the host application does not freeze and remains responsive.

If Timeout expires, and the operation is not yet complete, the component raises an exception.

Note: By default, all timeouts are inactivity timeouts, that is, the timeout period is extended by Timeout seconds when any amount of data is successfully sent or received.

The default value for the Timeout property is 60 seconds.

TransferredData Property (RSS Component)

This property includes the contents of the last response from the server.

Syntax

property TransferredData: String read get_TransferredData;
property TransferredDataB: TBytes read get_TransferredDataB;

Default Value

''

Remarks

This property contains the contents of the last response from the server. If the LocalFile is empty, the data are accumulated in TransferredData and also can be received in the Transfer event. Otherwise, this property returns an empty string.

TransferredDataLimit controls the maximum amount of data accumulated in TransferredData (by default there is no limit).

This property is read-only and not available at design time.

TransferredDataLimit Property (RSS Component)

This property includes the maximum number of bytes of data to be transferred.

Syntax

property TransferredDataLimit: Int64 read get_TransferredDataLimit write set_TransferredDataLimit;

Default Value

0

Remarks

This property defines the maximum number of bytes of data to be transferred. The default value is zero, which means there is no limit to the amount of data the component will accumulate and parse. If this value is set to a number n that is greater than zero, the component will receive only the first n bytes of data from the server.

TransferredHeaders Property (RSS Component)

The full set of headers as received from the server.

Syntax

property TransferredHeaders: String read get_TransferredHeaders;

Default Value

''

Remarks

This property returns the complete set of raw headers as received from the server.

The Header event shows the individual headers as parsed by the component.

This property is read-only and not available at design time.

User Property (RSS Component)

This property includes a user name if authentication is to be used.

Syntax

property User: String read get_User write set_User;

Default Value

''

Remarks

This property contains a user name if authentication is to be used. If AuthScheme is set to HTTP Basic Authentication, The User and Password are Base64 encoded, and the result is put in the Authorization property in the form 'Basic [encoded-user-password]'.

If AuthScheme is set to HTTP Digest Authentication, the User and Password properties are used to respond to the HTTP Digest Authentication challenge from the server.

If AuthScheme is set to NTLM, NTLM authentication will be attempted. If AuthScheme is set to NTLM, and User and Password are empty, the component will attempt to authenticate using the current user's credentials.

AddCookie Method (RSS Component)

Adds a cookie and the corresponding value to the outgoing request headers.

Syntax

procedure AddCookie(CookieName: String; CookieValue: String);

Remarks

This method adds a cookie and the corresponding value to the outgoing request headers. Please refer to the Cookies property for more information on cookies and how they are managed.

AddItem Method (RSS Component)

This method inserts a new item into the beginning of an RSS feed.

Syntax

procedure AddItem(Title: String; Description: String; Link: String);

Remarks

This method assumes that the items are new and more important than existing items and thus adds the item to the beginning of the current item list. This method requires the three standard fields Title, Description, and Link to be specified.

Example 1. Add a New Item: RSSControl.AddItem("New Item Title", "Item Description", "http://www.itemsource.com") RSSControl.WriteFile(filename) Example 2. Add a New Item Using the Item Arrays: RSSControl.ItemCount = 1 RSSControl.ItemTitle(0) = "New Item Title" RSSControl.ItemDescription(0) = "Item Description" RSSControl.ItemLink(0) = "http://www.itemsource.com" RSSControl.WriteFile(filename)

AddNamespace Method (RSS Component)

This method adds a namespace to the Namespaces properties.

Syntax

procedure AddNamespace(Prefix: String; NamespaceURI: String);

Remarks

This method adds a namespace to the Namespaces properties. Prefix specifies the namespace prefix, and NamespaceURI specifies the namespace.

Config Method (RSS Component)

Sets or retrieves a configuration setting.

Syntax

function Config(ConfigurationString: String): String;

Remarks

Config is a generic method available in every component. It is used to set and retrieve configuration settings for the component.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

DoEvents Method (RSS Component)

This method processes events from the internal message queue.

Syntax

procedure DoEvents();

Remarks

When DoEvents is called, the component processes any available events. If no events are available, it waits for a preset period of time, and then returns.

GetFeed Method (RSS Component)

This method retrieves an RSS feed.

Syntax

procedure GetFeed(URL: String);

Remarks

This method retrieves documents using the HTTP GET method. The document contents are delivered in the RSSData property, as well as through the Transfer event, and the HTTP response headers through the Header event. If the LocalFile property has been set, the component will write the transferred data there.

The component will then attempt to parse the RSS feed, filling in the channel and item properties as it goes. The feed properties can be accessed either directly through the named properties, or through the GetProperty and SetProperty methods.

GetProperty Method (RSS Component)

This method gets the value of a specific RSS feed item element or attribute.

Syntax

function GetProperty(PropertyName: String): String;

Remarks

This method is intended to extend the functionality of the RSS component. It will get the value for a specific item element or attribute of this RSS feed. Property is the XPath of the element or attribute according to the following convention: root/element@attribute. The @attribute part is optional, and the root field can be any of the four following values:

The element field can be any property of the root field, and attribute can be any property of that field. If an attribute is not supplied, this method will return the text portion of element.

Example. GetProperty:

RSSControl.GetProperty("item[5]/guid@isPermaLink") RSSControl.GetProperty("item[5]/link") RSSControl.GetProperty("/channel/title")

Note: To add nonstandard fields (i.e., fields that are not defined in the RSS specification), element must be prefixed with a namespace that defines that field. The same applies for the attribute field. Use the Namespaces properties to define and list namespaces.

GetURL Method (RSS Component)

This method retrieves an RSS feed.

Syntax

procedure GetURL(URL: String);

Remarks

This method retrieves the document using the HTTP GET method. The document contents are delivered in the RSSData property, as well as through the Transfer event, and the HTTP response headers are delivered through the Header event. If the LocalFile property has been set, the component will write the transferred data there.

The component will not parse the data returned by the server. For more control over the retrieval of the item link, please use the HTTP component.

Interrupt Method (RSS Component)

This method interrupts the current method.

Syntax

procedure Interrupt();

Remarks

If there is no method in progress, Interrupt simply returns, doing nothing.

If there is no method in progress, Interrupt simply returns, doing nothing.

OPMLAttr Method (RSS Component)

This method returns the value of the attribute specified in the parameter.

Syntax

function OPMLAttr(AttrName: String): String;

Remarks

This method may be used to get the value of an attribute for an outline entry of an OPML document. The desired attribute must be specified in the parameter of this method. This method also must be invoked inside the OPMLOutline event.

Put Method (RSS Component)

This method sends data to the HTTP server using the HTTP PUT method.

Syntax

procedure Put(URL: String);

Remarks

This method sends data to the HTTP server. The data are taken from the PostData or AttachedFile properties. The server response text is received through the Transfer event, and the HTTP response headers are received through the Header event. If LocalFile is not empty, the data (not the headers) are written there as well. The user normally should have assigned the correct values to User and Password or Authorization.

ReadFile Method (RSS Component)

This method loads an RSS file into the component.

Syntax

procedure ReadFile(FileName: String);

Remarks

This method loads an RSS file and attempts to parse it, filling in the properties as it goes. The feed properties can be accessed either directly through the named properties or through the GetProperty and SetProperty methods.

ReadOPML Method (RSS Component)

This method reads and parses an OPML file.

Syntax

procedure ReadOPML(OPMLFile: String);

Remarks

This method reads in the OPML file specified by OPMLFile. The component then parses the file and returns the data to the user in the OPMLHeader and OPMLOutline events.

Reset Method (RSS Component)

This method resets all properties of the component.

Syntax

procedure Reset();

Remarks

This method resets all properties to the component's default settings. This is an easy way to clear all of the property values before repopulating the RSS feed.

SetProperty Method (RSS Component)

This method sets the value of a specific RSS feed property.

Syntax

procedure SetProperty(PropertyName: String; PropertyValue: String);

Remarks

This method is intended to extend the functionality of the RSS component. It will set the value for a specific field of this RSS feed. Property is the name of the property according to the following convention: root/element@attribute. The root field can be any of the four following values:

The element field can be any property of the root field, and attribute can be any property of that field. If an attribute is not supplied, Value will be placed in the text portion of element. Example. SetProperty:

RSSControl.SetProperty("item[5]/guid@isPermaLink", "true")

Note: To add nonstandard fields (i.e., fields that are not defined in the RSS specification), element must be prefixed with a namespace that defines that field. The same applies for the attribute field. Use the Namespaces properties to define and list namespaces.

WriteFile Method (RSS Component)

This method writes an RSS feed from the component.

Syntax

procedure WriteFile(FileName: String);

Remarks

This method will write an RSS feed from the existing property values to FileName. The RSS feed will be preverified, and if there are any missing required fields, the component raises an exception.

Example 1. Add a New Item: RSSControl.AddItem("New Item Title", "Item Description", "http://www.itemsource.com") RSSControl.WriteFile(filename) Example 3. Add a New Item Using the Item Arrays: RSSControl.ItemCount = 1 RSSControl.ItemTitle(0) = "New Item Title" RSSControl.ItemDescription(0) = "Item Description" RSSControl.ItemLink(0) = "http://www.itemsource.com" RSSControl.WriteFile(filename)

Connected Event (RSS Component)

Fired immediately after a connection completes (or fails).

Syntax

type TConnectedEvent = procedure (
  Sender: TObject;
  StatusCode: Integer;
  const Description: String
) of Object;

property OnConnected: TConnectedEvent read FOnConnected write FOnConnected;

Remarks

If the connection is made normally, StatusCode is 0 and Description is 'OK'.

If the connection fails, StatusCode has the error code returned by the Transmission Control Protocol (TCP)/IP stack. Description contains a description of this code. The value of StatusCode is equal to the value of the error.

Please refer to the Error Codes section for more information.

ConnectionStatus Event (RSS Component)

Fired to indicate changes in the connection state.

Syntax

type TConnectionStatusEvent = procedure (
  Sender: TObject;
  const ConnectionEvent: String;
  StatusCode: Integer;
  const Description: String
) of Object;

property OnConnectionStatus: TConnectionStatusEvent read FOnConnectionStatus write FOnConnectionStatus;

Remarks

This event is fired when the connection state changes: for example, completion of a firewall or proxy connection or completion of a security handshake.

The ConnectionEvent parameter indicates the type of connection event. Values may include the following:

Disconnected Event (RSS Component)

Fired when a connection is closed.

Syntax

type TDisconnectedEvent = procedure (
  Sender: TObject;
  StatusCode: Integer;
  const Description: String
) of Object;

property OnDisconnected: TDisconnectedEvent read FOnDisconnected write FOnDisconnected;

Remarks

If the connection is broken normally, StatusCode is 0 and Description is 'OK'.

If the connection is broken for any other reason, StatusCode has the error code returned by the Transmission Control Protocol (TCP/IP) subsystem. Description contains a description of this code. The value of StatusCode is equal to the value of the TCP/IP error.

Please refer to the Error Codes section for more information.

EndTransfer Event (RSS Component)

This event is fired when a document finishes transferring.

Syntax

type TEndTransferEvent = procedure (
  Sender: TObject;
  Direction: Integer
) of Object;

property OnEndTransfer: TEndTransferEvent read FOnEndTransfer write FOnEndTransfer;

Remarks

The EndTransfer event is fired when the document text finishes transferring from the server to the local host.

The Direction parameter shows whether the client (0) or the server (1) is sending the data.

Error Event (RSS Component)

Fired when information is available about errors during data delivery.

Syntax

type TErrorEvent = procedure (
  Sender: TObject;
  ErrorCode: Integer;
  const Description: String
) of Object;

property OnError: TErrorEvent read FOnError write FOnError;

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the component raises an exception.

The ErrorCode parameter contains an error code, and the Description parameter contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

Header Event (RSS Component)

Fired every time a header line comes in.

Syntax

type THeaderEvent = procedure (
  Sender: TObject;
  const Field: String;
  const Value: String
) of Object;

property OnHeader: THeaderEvent read FOnHeader write FOnHeader;

Remarks

The Field parameter contains the name of the HTTP header (which is the same as it is delivered). The Value parameter contains the header contents.

If the header line being retrieved is a continuation header line, then the Field parameter contains '' (empty string).

Log Event (RSS Component)

Fired once for each log message.

Syntax

type TLogEvent = procedure (
  Sender: TObject;
  LogLevel: Integer;
  const Message: String;
  const LogType: String
) of Object;

property OnLog: TLogEvent read FOnLog write FOnLog;

Remarks

This event is fired once for each log message generated by the component. The verbosity is controlled by the LogLevel setting.

LogLevel indicates the level of message. Possible values are as follows:

The value 1 (Info) logs basic information, including the URL, HTTP version, and status details.

The value 2 (Verbose) logs additional information about the request and response.

The value 3 (Debug) logs the headers and body for both the request and response, as well as additional debug information (if any).

Message is the log entry.

LogType identifies the type of log entry. Possible values are as follows:

• "Info"
• "RequestHeaders"
• "ResponseHeaders"
• "RequestBody"
• "ResponseBody"
• "ProxyRequest"
• "ProxyResponse"
• "FirewallRequest"
• "FirewallResponse"

OPMLHeader Event (RSS Component)

This event is fired for each value in the header section of the current OPML document.

Syntax

type TOPMLHeaderEvent = procedure (
  Sender: TObject;
  const Field: String;
  const Value: String
) of Object;

property OnOPMLHeader: TOPMLHeaderEvent read FOnOPMLHeader write FOnOPMLHeader;

Remarks

This event is fired when the component is parsing an OPML document after a call to ReadOPML is made. The component parses each header field and value from the OPML document and fires OPMLHeader once for each header present.

OPMLOutline Event (RSS Component)

This event is fired for each outline in the current OPML document.

Syntax

type TOPMLOutlineEvent = procedure (
  Sender: TObject;
  Level: Integer;
  const Text: String;
  const TypeName: String;
  const Title: String;
  const URL: String;
  const XMLURL: String;
  const HTMLURL: String;
  const Created: String;
  const Description: String;
  const OtherAttrs: String
) of Object;

property OnOPMLOutline: TOPMLOutlineEvent read FOnOPMLOutline write FOnOPMLOutline;

Remarks

This event is fired for each outline in the OPML document.

The Level parameter contains the depth of the current outline in the OPML document.

Each outline contains a Text attribute, which is parsed out, and returned in the Text parameter.

The Type attribute is a string that describes how the other attributes of the outline are interpreted and is returned in the TypeName parameter.

The Title parameter refers to the title of the outline.

The URL parameter indicates the external location of the outline.

The XMLURL parameter is usually set to an RSS, Atom, or OPML file.

The HTMLURL parameter specifies an HTMLURL attribute, which may be used instead of the URL attribute.

The Created parameter contains the date the outline node was created.

The OtherAttrs parameter contains a list of other attributes for the current outline. In this case, you must use the OPMLAttr method to get the attribute's corresponding values from the parser.

Redirect Event (RSS Component)

Fired when a redirection is received from the server.

Syntax

type TRedirectEvent = procedure (
  Sender: TObject;
  const Location: String;
  var Accept: Boolean
) of Object;

property OnRedirect: TRedirectEvent read FOnRedirect write FOnRedirect;

Remarks

This event is fired in cases in which the client can decide whether or not to continue with the redirection process. The Accept parameter is always True by default, but if you do not want to follow the redirection, Accept may be set to False, in which case the component raises an exception. Location is the location to which the client is being redirected. Further control over redirection is provided in the FollowRedirects property.

SetCookie Event (RSS Component)

Fired for every cookie set by the server.

Syntax

type TSetCookieEvent = procedure (
  Sender: TObject;
  const Name: String;
  const Value: String;
  const Expires: String;
  const Domain: String;
  const Path: String;
  Secure: Boolean
) of Object;

property OnSetCookie: TSetCookieEvent read FOnSetCookie write FOnSetCookie;

Remarks

This event is fired for every Set-Cookie: header received from the HTTP server.

The Name parameter contains the name of the cookie, with the corresponding value supplied in the Value parameter.

The Expires parameter contains an expiration time for the cookie (if provided by the server). The time format used is "Weekday, DD-Mon-YY HH:MM:SS GMT". If the server does not provide an expiration time, the Expires parameter will be an empty string. In this case, the convention is to drop the cookie at the end of the session.

The Domain parameter contains a domain name to limit the cookie to (if provided by the server). If the server does not provide a domain name, the Domain parameter will be an empty string. The convention in this case is to use the server specified in the URL (URLServer) as the cookie domain.

The Path parameter contains a path name to limit the cookie to (if provided by the server). If the server does not provide a cookie path, the Path parameter will be an empty string. The convention in this case is to use the path specified in the URL (URLPath) as the cookie path.

The Secure parameter specifies whether the cookie is secure. If the value of this parameter is True, the cookie value must be submitted only through a secure (HTTPS) connection.

SSLServerAuthentication Event (RSS Component)

Fired after the server presents its certificate to the client.

Syntax

type TSSLServerAuthenticationEvent = procedure (
  Sender: TObject;
  const CertEncoded: String;
  const CertEncodedB: TBytes;
  const CertSubject: String;
  const CertIssuer: String;
  const Status: String;
  var Accept: Boolean
) of Object;

property OnSSLServerAuthentication: TSSLServerAuthenticationEvent read FOnSSLServerAuthentication write FOnSSLServerAuthentication;

Remarks

During this event, the client can decide whether or not to continue with the connection process. The Accept parameter is a recommendation on whether to continue or close the connection. This is just a suggestion: application software must use its own logic to determine whether or not to continue.

When Accept is False, Status shows why the verification failed (otherwise, Status contains the string OK). If it is decided to continue, you can override and accept the certificate by setting the Accept parameter to True.

SSLStatus Event (RSS Component)

Fired when secure connection progress messages are available.

Syntax

type TSSLStatusEvent = procedure (
  Sender: TObject;
  const Message: String
) of Object;

property OnSSLStatus: TSSLStatusEvent read FOnSSLStatus write FOnSSLStatus;

Remarks

The event is fired for informational and logging purposes only. This event tracks the progress of the connection.

StartTransfer Event (RSS Component)

This event is fired when a document starts transferring (after the headers).

Syntax

type TStartTransferEvent = procedure (
  Sender: TObject;
  Direction: Integer
) of Object;

property OnStartTransfer: TStartTransferEvent read FOnStartTransfer write FOnStartTransfer;

Remarks

The StartTransfer event is fired when the document text starts transferring from the server to the local host.

The Direction parameter shows whether the client (0) or the server (1) is sending the data.

Status Event (RSS Component)

Fired when the HTTP status line is received from the server.

Syntax

type TStatusEvent = procedure (
  Sender: TObject;
  const HTTPVersion: String;
  StatusCode: Integer;
  const Description: String
) of Object;

property OnStatus: TStatusEvent read FOnStatus write FOnStatus;

Remarks

HTTPVersion is a string containing the HTTP version string as returned from the server (e.g., "1.1").

StatusCode contains the HTTP status code (e.g., 200), and Description the associated message returned by the server (e.g., "OK").

Transfer Event (RSS Component)

Fired while a document transfers (delivers document).

Syntax

type TTransferEvent = procedure (
  Sender: TObject;
  Direction: Integer;
  BytesTransferred: Int64;
  PercentDone: Integer;
  const Text: String;
  const TextB: TBytes
) of Object;

property OnTransfer: TTransferEvent read FOnTransfer write FOnTransfer;

Remarks

The Text parameter contains the portion of the document text being received. It is empty if data are being posted to the server.

The BytesTransferred parameter contains the number of bytes transferred in this Direction since the beginning of the document text (excluding HTTP response headers).

The Direction parameter shows whether the client (0) or the server (1) is sending the data.

The PercentDone parameter shows the progress of the transfer in the corresponding direction. If PercentDone can not be calculated the value will be -1.

Note: Events are not re-entrant. Performing time-consuming operations within this event will prevent it from firing again in a timely manner and may affect overall performance.

Certificate Type

This is the digital certificate being used.

Remarks

This type describes the current digital certificate. The certificate may be a public or private key. The fields are used to identify or select certificates.

Fields

Constructors

>

constructor Create();

constructor Create(valEncoded: TBytes);

constructor Create(valStoreType: TipwCertStoreTypes; valStore: String; valStorePassword: String; valSubject: String);

constructor Create(valStoreType: TipwCertStoreTypes; valStore: TBytes; valStorePassword: String; valSubject: String);

Firewall Type

The firewall the component will connect through.

Remarks

When connecting through a firewall, this type is used to specify different properties of the firewall, such as the firewall Host and the FirewallType.

Fields

Constructors

constructor Create();

Header Type

This is an HTTP header as it is received from the server.

Remarks

When a header is received through a Header event, it is parsed into a Header type. This type contains a Field, and its corresponding Value.

Fields

Constructors

constructor Create();

constructor Create(valField: String; valValue: String);

HTTPCookie Type

An HTTP cookie can be either sent to or received from the server.

Remarks

An HTTP cookie can store the cookies that are to be sent to the server. It also may store the cookies sent by the server.

Cookies that are to be sent to the server must have the Name and Value fields supplied before submitting the URL. When the SetCookie event is fired, however, all of the fields of an HTTPCookie are filled out accordingly.

Fields

Constructors

constructor Create();

constructor Create(valName: String; valValue: String);

Proxy Type

The proxy the component will connect to.

Remarks

When connecting through a proxy, this type is used to specify different properties of the proxy, such as the Server and the AuthScheme.

Fields

Constructors

constructor Create();

constructor Create(valServer: String; valPort: Integer);

constructor Create(valServer: String; valPort: Integer; valUser: String; valPassword: String);

RSSChannel Type

This is the information about an RSS feed as received from the server.

Remarks

When an RSS feed is parsed by the component, each item is parsed into an rssitem type and other information about the feed is presented as RSSChannel.

Fields

Constructors

constructor Create();

constructor Create(valTitle: String; valDescription: String);

RSSItem Type

This is an RSS item as it is received from the RSS feed.

Remarks

When an RSS feed is parsed by the component, each item is parsed into an RSSItem type. This type contains field value pairs for standard RSS 2.0 elements.

Fields

Constructors

constructor Create();

constructor Create(valTitle: String; valDescription: String);

XMLNamespace Type

This type describes an XML namespace from the current namespace stack.

Remarks

This type describes an XML namespace from the current stack. It includes fields to denote the Prefix and the URI of the namespace being defined.

The default namespace exists at index 0. The Prefix field at index 0 is xmlns, and the Name field contains the default namespace.

Fields

Constructors

constructor Create();

constructor Create(valURI: String; valPrefix: String);

Config Settings (RSS Component)

RSS Config Settings

HTTP Config Settings

TCPClient Config Settings

SSL Config Settings

-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
... Intermediate Cert ...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
... Root Cert ...
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----

-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
... Intermediate Cert ...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
... Root Cert ...
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----

-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
... Intermediate Cert...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
... Root Cert...
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----

Socket Config Settings

Base Config Settings

Trappable Errors (RSS Component)

RSS Errors

The component may also return one of the following error codes, which are inherited from other components.

HTTP Errors

The component may also return one of the following error codes, which are inherited from other components.

TCPClient Errors

SSL Errors

TCP/IP Errors

XML Errors