## wxFileSystemHandler

Classes derived from wxFileSystemHandler are used to access virtual file systems. Its public interface consists of two methods: CanOpen and OpenFile. It provides additional protected methods to simplify the process of opening the file: GetProtocol, GetLeftLocation, GetRightLocation, GetAnchor, GetMimeTypeFromExt.

Please have a look at overview if you don't know how locations are constructed.

Also consult list of available handlers.

wxPerl note: In wxPerl, you need to derive your file system handler class from Wx::PlFileSystemHandler.

Notes

- The handlers are shared by all instances of wxFileSystem.
- wxHTML library provides handlers for local files and HTTP or FTP protocol
- The location parameter passed to OpenFile or CanOpen methods is always an absolute path. You don't need to check the FS's current path.

Derived from

wxObject

Include files

<wx/filesys.h>

See also

wxFileSystem, wxFSFile, Overview

Members

wxFileSystemHandler::wxFileSystemHandler
wxFileSystemHandler::CanOpen
wxFileSystemHandler::GetAnchor
wxFileSystemHandler::GetLeftLocation
wxFileSystemHandler::GetMimeTypeFromExt
wxFileSystemHandler::GetProtocol
wxFileSystemHandler::GetRightLocation
wxFileSystemHandler::FindFirst
wxFileSystemHandler::FindNext
wxFileSystemHandler::OpenFile

### wxFileSystemHandler::wxFileSystemHandler

wxFileSystemHandler()

Constructor.

### wxFileSystemHandler::CanOpen

virtual bool CanOpen(const wxString& location)

Returns TRUE if the handler is able to open this file. This function doesn't check whether the file exists or not, it only checks if it knows the protocol. Example:

    bool MyHand::CanOpen(const wxString& location)
    {
        return (GetProtocol(location) == "http");
    }

Must be overridden in derived handlers.

### wxFileSystemHandler::GetAnchor

wxString GetAnchor(const wxString& location) const

Returns the anchor if present in the location. See wxFSFile for details.

Example: GetAnchor("index.htm#chapter2") == "chapter2"

Note: the anchor is NOT part of the left location.

### wxFileSystemHandler::GetLeftLocation

wxString GetLeftLocation(const wxString& location) const

Returns the left location string extracted from location.

Example: GetLeftLocation("file:myzipfile.zip#zip:index.htm") == "file:myzipfile.zip"

### wxFileSystemHandler::GetMimeTypeFromExt

wxString GetMimeTypeFromExt(const wxString& location)

Returns the MIME type based on extension of location. (While wxFSFile::GetMimeType returns real MIME type - either extension-based or queried from HTTP.)

Example : GetMimeTypeFromExt("index.htm") == "text/html"

### wxFileSystemHandler::GetProtocol

wxString GetProtocol(const wxString& location) const

Returns the protocol string extracted from location.

Example: GetProtocol("file:myzipfile.zip#zip:index.htm") == "zip"

### wxFileSystemHandler::GetRightLocation

wxString GetRightLocation(const wxString& location) const

Returns the right location string extracted from location.

Example : GetRightLocation("file:myzipfile.zip#zip:index.htm") == "index.htm"

### wxFileSystemHandler::FindFirst

virtual wxString FindFirst(const wxString& wildcard, int flags = 0)

Works like wxFindFirstFile. Returns name of the first filename (within filesystem's current path) that matches wildcard. flags may be one of wxFILE (only files), wxDIR (only directories) or 0 (both).

This method is only called if CanOpen returns TRUE.

### wxFileSystemHandler::FindNext

virtual wxString FindNext()

Returns next filename that matches parameters passed to FindFirst.

This method is only called if CanOpen returns TRUE and FindFirst returned a non-empty string.

### wxFileSystemHandler::OpenFile

virtual wxFSFile* OpenFile(wxFileSystem& fs, const wxString& location)

Opens the file and returns wxFSFile pointer or NULL if failed.

Must be overridden in derived handlers.

Parameters

fs

Parent FS (the FS from that OpenFile was called). See ZIP handler for details of how to use it.

location

The absolute location of file.