File Transfer ============= The file transfer extension allows the user to transmit and receive files. * Send a file to another user * Recieving a file from another user * Monitoring the progress of a file transfer **XEP related:** [XEP-95](http://www.xmpp.org/extensions/xep-0095.html) [XEP-96](http://www.xmpp.org/extensions/xep-0096.html) [XEP-65](http://www.xmpp.org/extensions/xep-0065.html) [XEP-47](http://www.xmpp.org/extensions/xep-0047.html) Send a file to another user --------------------------- **Description** A user may wish to send a file to another user. The other user has the option of acception, rejecting, or ignoring the users request. Smack provides a simple interface in order to enable the user to easily send a file. **Usage** In order to send a file you must first construct an instance of the **_FileTransferManager_** class. In order to instantiate the manager you should call _FileTransferManager.getInstanceFor(connection)_ Once you have your **_FileTransferManager_** you will need to create an outgoing file transfer to send a file. The method to use on the **_FileTransferManager_** is the **createOutgoingFileTransfer(userID)** method. The userID you provide to this method is the fully-qualified jabber ID of the user you wish to send the file to. A fully-qualified jabber ID consists of a node, a domain, and a resource, the user must be connected to the resource in order to be able to recieve the file transfer. Now that you have your **_OutgoingFileTransfer_** instance you will want to send the file. The method to send a file is **sendFile(file, description)**. The file you provide to this method should be a readable file on the local file system, and the description is a short description of the file to help the user decide whether or not they would like to recieve the file. For information on monitoring the progress of a file transfer see the monitoring progress section of this document. Other means to send a file are also provided as part of the **_OutgoingFileTransfer_**. Please consult the Javadoc for more information. **Examples** In this example we can see how to send a file: ``` // Create the file transfer manager FileTransferManager manager = FileTransferManager.getInstanceFor(connection); // Create the outgoing file transfer OutgoingFileTransfer transfer = manager.createOutgoingFileTransfer("romeo@montague.net"); // Send the file transfer.sendFile(new File("shakespeare_complete_works.txt"), "You won't believe this!"); ``` Recieving a file from another user ---------------------------------- **Description** The user may wish to recieve files from another user. The process of recieving a file is event driven, new file transfer requests are recieved from other users via a listener registered with the file transfer manager. **Usage** In order to recieve a file you must first construct an instance of the **_FileTransferManager_** class. This class has one constructor with one parameter which is your XMPPConnection. In order to instantiate the manager you should call _FileTransferManager.getInstanceFor(connection)_ Once you have your **_FileTransferManager_** you will need to register a listener with it. The FileTransferListner interface has one method, **fileTransferRequest(request)**. When a request is recieved through this method, you can either accept or reject the request. To help you make your decision there are several methods in the **_FileTransferRequest_** class that return information about the transfer request. To accept the file transfer, call the **accept()**, this method will create an **_IncomingFileTransfer_**. After you have the file transfer you may start to transfer the file by calling the **recieveFile(file)** method. The file provided to this method will be where the data from thefile transfer is saved. Finally, to reject the file transfer the only method you need to call is **reject()** on the **_IncomingFileTransfer_**. For information on monitoring the progress of a file transfer see the monitoring progress section of this document. Other means to recieve a file are also provided as part of the **_IncomingFileTransfer_**. Please consult the Javadoc for more information. **Examples** In this example we can see how to approve or reject a file transfer request: ``` // Create the file transfer manager final FileTransferManager manager = FileTransferManager.getInstanceFor(connection); // Create the listener manager.addFileTransferListener(new FileTransferListener() { public void fileTransferRequest(FileTransferRequest request) { // Check to see if the request should be accepted if(shouldAccept(request)) { // Accept it IncomingFileTransfer transfer = request.accept(); transfer.recieveFile(new File("shakespeare_complete_works.txt")); } else { // Reject it request.reject(); } } }); ``` Monitoring the progress of a file transfer ------------------------------------------ **Description** While a file transfer is in progress you may wish to monitor the progress of a file transfer. **Usage** Both the **_IncomingFileTransfer_** and the **_OutgoingFileTransfer_** extend the **_FileTransfer_** class which provides several methods to monitor how a file transfer is progressing: * **getStatus()** - The file transfer can be in several states, negotiating, rejected, canceled, in progress, error, and complete. This method will return which state the file transfer is currently in. * **getProgress()** - if the status of the file transfer is in progress this method will return a number between 0 and 1, 0 being the transfer has not yet started and 1 being the transfer is complete. It may also return a -1 if the transfer is not in progress. * **isDone()** - Similar to getProgress() except it returns a _boolean_. If the state is rejected, canceled, error, or complete then true will be returned and false otherwise. * **getError()** - If there is an error during the file transfer this method will return the type of error that occured. **Examples** In this example we can see how to monitor a file transfer: ``` while(!transfer.isDone()) { if(transfer.getStatus().equals(Status.ERROR)) { System.out.println("ERROR!!! " + transfer.getError()); } else { System.out.println(transfer.getStatus()); System.out.println(transfer.getProgress()); } sleep(1000); } ```