Implements a Gopher client.

TIdGopher = class(TIdTCPClient)

The TIdGopher is a client implementation of the Internet Gopher protocol (RFC 1436) as described in the Internet Standards document:

• RFC 1436- The Internet Gopher Protocol (http://www.rfc-editor.org/rfc/rfc1436.txt)

TIdGopher also implements partial support for the Gopher+ protocol as described in the document:

• Gopher+, Upward-Compatible Enhancements to the Internet Gopher protocol (http://boombox.micro.umn.edu/pub/gopher/gopher_protocol/Gopher+/Gopher+.txt)

Gopher is a distributed document system developed at the University of Minnesota as an attempt to make locating information resources intuitive for users through a series of structured menus leading to documents or pointers to other protocols such as Telnet and TN3270. While this has been succeeded by the World Wide Web, this is still useful for accessing legacy systems and has a low overhead due to its simplicity and structure.

Port number for the connection to the Gopher server.

property Port: integer;

Port is an Integer property that identifies the port number used for connecting to a Gopher server. TIdGopher overrides the definition of the Port property to assign the default value to IdPORT_GOPHER, as required in the Gopher protocol specification.

Instantiates a TIdGopher instance.

constructor Create(AOwner: TComponent); override;

Owner of the object instance.

Create constructs a properly initialized instance of TIdGopher using the inherited Create constructor, and initializes Port to the constant value IdPORT_GOPHER (Decimal 70) as required by the Gopher Protocol.

Gets the Gopher+ extended menu.

function GetExtendedMenu(ASelector: String; AView: String = ''): TIdGopherMenu;

the selector used to retrieve the gopher menu AView - alternative views listed for the item you are retrieving for a Gopher + server.

TIdGopherMenu - Gopher+ extended menu or standard menu.

GetExtendedMenu is a TIdGopherMenu function that gets an extended Gopher+ menu including additional Gopher+ information. GetExtendedMenu will also retrieve the standard Gopher menu if the server does not support Gopher+.

We do not recommend that you use this procedure unless you are sure the server supports Gopher+ because a constant used in the Gopher+ Protocol greeting will conflict with the menu item type constant IdGopherItem_Redundant which could appear in the menu as a first item. To determine if a Gopher Server supports Gopher+, use the TIdGopherMenuItem.GopherPlusItem property from the gopher menu which is referring to the item you want.

The application is responsible for freeing the TIdGopherMenu returned by this function.

Retrieve a Gopher Binary File.

procedure GetFile(ASelector: String; ADestStream: TStream; IsGopherPlus: Boolean = False; AView: String = '');

the selector used to retrieve the file.

DEstination for the retrieved file.

Server supports Gopher+. Default value is False.

Alternate view listed. Default value is ''.

GetFile is a procedure used to retrieve a binary Gopher File and store its content in ADestStream. ISGopherPlus should be set to True for Gopher+ servers, or False for non-Gopher+ servers where a file name can start with "+". AView is an alternative view listed for the file you are retrieving with Gopher+.

If you are retrieving a text file, use the GetTextFile method because GetFile will include the "." end of text file marker.

Retrieves the Gopher menu.

function GetMenu(ASelector: String; IsGopherPlus: Boolean = False; AView: String = ''): TIdGopherMenu;

the selector for the Gopher item or an empty string to get the root item. IsGopherPlus - Server supports Gopher+. Default value is False.

Alternative view listed. Default value is ''.

TIdGopherMenu - The standard Gopher menu.

GetMenu is a TIdGopherMenu function used to retrieve a Gopher Menu. ISGopherPlus should be set to true for Gopher+ servers or false for non-gopher plus servers in case a menu starts with a "+". AView is an alternative view listed for the menu you are retrieving with Gopher+.

The application is responsible for freeing the TIdGopherMenu returned by this function.

Retrieve a Gopher text File.

procedure GetTextFile(ASelector: String; ADestStream: TStream; IsGopherPlus: Boolean = False; AView: String = '');

the selector used to retrieve the file.

DEstination for the retrieved file.

Server supports Gopher+. Default value is False.

Alternate view listed. Default value is ''.

GetTextFile is a procedure used to retrieve a Gopher Text File and store its content in ADestStream. ISGopherPlus should be set to True for Gopher+ servers, or False for non-Gopher+ servers where a file name can start with "+". AView is an alternative view listed for the file you are retrieving with Gopher+.

If you are retrieving a text file, use the GetFile method because GetTextFile will stop reading if it encounters the "." end of text file marker.

Perform a Gopher search using a query.

function Search(ASelector: String; AQuery: String): TIdGopherMenu;

the selector for the gopher item AQuery - the Gopher query string.

TIdGopherMenu - The Gopher menu returned for the query.

Search is a TIdGopherMenu function used to perform a Gopher search with the query specified by AQuery, and returns a Gopher Menu resulting from the search. Gopher+ syntax is not supported in AQuery.

The application is responsible for freeing the TIdGopherMenu returned by this function.

Event handler for retrieved Gopher menu items.

property OnMenuItem: TIdGopherMenuEvent;

The menu item retrieved from the server.

Gopher menu that own the menu item.

OnMenuItem is a TIdGopherMenuEvent event handler that is triggered for each menu item retrieved with the GetMenu, Search, and GetExtendedMenu methods. OnMenuItem is used to display gopher menu items while the complete menu is downloaded.

An application must assign a procedure to the event handler in order to respond to the event notification.