Using the FileReference class
Flash Player 9 and later, Adobe AIR 1.0 and later
A FileReference object represents a data file on a client or
server machine. The methods of the FileReference class let your
application load and save data files locally, and transfer file
data to and from remote servers.
The FileReference class offers two different approaches to loading,
transferring, and saving data files. Since its introduction, the
FileReference class has includedthe
browse()
method,
the
upload()
method, and the
download()
method.
Use the
browse()
method to let the user select
a file. Use the
upload()
method to transfer the
file data to a remote server. Use the
download()
method
to retrieve that data from the server and save it in a local file.
Starting with Flash Player 10 and Adobe AIR 1.5, the FileReference
class includes the
load()
and
save()
methods.
The
load()
and
save()
methods
allow you to access and save local files directly as well. The use
of those methods is similar to the equivalent-named methods in the
URLLoader and Loader classes.
Note:
The File class, which extends
the FileReference class, and the FileStream class provide additional
functions for working with files and the local file system. The
File and FileStream classes are only supported in AIR and not in
the Flash Player.
FileReference class
Each FileReference
object represents a single data file on the local machine. The properties
of the FileReference class contain information about the file’s
size, type, name, filename extension, creator, creation date, and modification
date.
Note:
The
creator
property is supported
on Mac OS only. All other platforms return
null
.
Note:
The
extension
property is only
supported in Adobe AIR.
You can create an instance of the FileReference class one of
two ways:
Once you have created a FileReference object, you can do the
following:
-
Call the
FileReference.browse()
method,
which opens a dialog box and prompts the user to select a single
file from the local file system. This is usually done before a subsequent
call to the
FileReference.upload()
method or
FileReference.load()
method.
Call the
FileReference.upload()
method to upload
the file to a remote server. Call to the
FileReference.load()
method
to open a local file.
-
Call the
FileReference.download()
method.
The
download()
method opens a dialog box to let
the user select a location for saving a new file. Then it downloads
data from the server and stores it in the new file.
-
Call the
FileReference.load()
method. This
method begins loading data from a file selected previously using
the
browse()
method. The
load()
method
can’t be called until the
browse()
operation completes
(the user selects a file).
-
Call the
FileReference.save()
method. This
method opens a dialog box and prompts the user to choose a single
file location on the local file system. It then saves data to the
specified location.
Note:
You can only perform one
browse()
,
download()
,
or
save()
action at a time, because only one dialog
box can be open at any point.
The FileReference object properties such as
name
,
size
,
or
modificationDate
are not defined until one of
the following happens:
-
The
FileReference.browse()
method or
FileReferenceList.browse()
method
has been called, and the user has selected a file using the dialog box.
-
The
FileReference.download()
method has
been called, and the user has specified a new file location using the
dialog box.
Note:
When performing a download, only the
FileReference.name
property
is populated before the download is complete. After the file has
been downloaded, all properties are available.
While calls to the
FileReference.browse()
,
FileReferenceList.browse()
,
FileReference.download()
,
FileReference.load()
,
or
FileReference.save()
methods are executing,
most players continue SWF file playback including dispatching events
and executing code.
For uploading and downloading operations, a SWF file can access
files only within its own domain, including any domains specified
by a policy file. You need to put a policy file on the server containing
the file if that server is not in the same domain as the SWF file
initiating the upload or download.
See
FileReference
.
Loading data from files
The
FileReference.load()
method
lets you load data from a local file into memory.
Note:
Your code must first call the
FileReference.browse()
method
to let the user select a file to load. This restriction does not
apply to content running in Adobe AIR in the application security
sandbox
The
FileReference.load()
method returns immediately
after being called, but the data being loaded isn’t available immediately.
The FileReference object dispatches events to invoke listener methods
at each step of the loading process.
The FileReference object dispatches the following events during
the loading process.
-
open
event (
Event.OPEN
):
Dispatched when the load operation starts.
-
progress
event (
ProgressEvent.PROGRESS
):
Dispatched periodically as bytes of data are read from the file.
-
complete
event (
Event.COMPLETE
):
Dispatched when the load operation completes successfully.
-
ioError
event (
IOErrorEvent.IO_ERROR
):
Dispatched if the load process fails because an input/output error
occurs while opening or reading data from the file.
Once the FileReference object dispatches the complete event,
the loaded data can be accessed as a ByteArray in the FileReference
object’s
data
property.
The following example shows how to prompt the user to select
a file and then load the data from that file into memory:
package
{
import flash.display.Sprite;
import flash.events.*;
import flash.net.FileFilter;
import flash.net.FileReference;
import flash.net.URLRequest;
import flash.utils.ByteArray;
public class FileReferenceExample1 extends Sprite
{
private var fileRef:FileReference;
public function FileReferenceExample1()
{
fileRef = new FileReference();
fileRef.addEventListener(Event.SELECT, onFileSelected);
fileRef.addEventListener(Event.CANCEL, onCancel);
fileRef.addEventListener(IOErrorEvent.IO_ERROR, onIOError);
fileRef.addEventListener(SecurityErrorEvent.SECURITY_ERROR,
onSecurityError);
var textTypeFilter:FileFilter = new FileFilter("Text Files (*.txt, *.rtf)",
"*.txt;*.rtf");
fileRef.browse([textTypeFilter]);
}
public function onFileSelected(evt:Event):void
{
fileRef.addEventListener(ProgressEvent.PROGRESS, onProgress);
fileRef.addEventListener(Event.COMPLETE, onComplete);
fileRef.load();
}
public function onProgress(evt:ProgressEvent):void
{
trace("Loaded " + evt.bytesLoaded + " of " + evt.bytesTotal + " bytes.");
}
public function onComplete(evt:Event):void
{
trace("File was successfully loaded.");
trace(fileRef.data);
}
public function onCancel(evt:Event):void
{
trace("The browse request was canceled by the user.");
}
public function onIOError(evt:IOErrorEvent):void
{
trace("There was an IO Error.");
}
public function onSecurityError(evt:Event):void
{
trace("There was a security error.");
}
}
}
The example code first creates the FileReference object named
fileRef
and
then calls its
browse()
method. The
browse()
method
opens a dialog box that prompts the user to select a file. When
a file is selected, the code invokes the
onFileSelected()
method.
This method adds listeners for the
progress
and
complete
events
and then calls the FileReference object’s
load()
method.
The other handler methods in the example simply output messages
to report on the progress of the load operation. When the loading
completes, the application displays the contents of the loaded file
using the
trace()
method.
In Adobe AIR, the FileStream class provides additional functionality
for reading data from a local file. See
Reading and writing files
.
Saving data to local files
The
FileReference.save()
method
lets you save data to a local file. It starts by opening a dialog
box to let the user enter a new filename and location to which to
save a file. After the user selects the filename and location, the
data is written to the new file. When the file is saved successfully,
the properties of the FileReference object are populated with the
properties of the local file.
Note:
Your
code can only call the
FileReference.save()
method
in response to a user-initiated event such as a mouse click or a
keypress event. Otherwise an error is thrown. This restriction does
not apply to content running in Adobe AIR in the application security
sandbox.
The
FileReference.save()
method returns immediately
after being called. The FileReference object then dispatches events to
call listener methods at each step of the file saving process.
The FileReference object dispatches the following events during
the file saving process:
-
select
event (
Event.SELECT
):
Dispatched when the user specifies the location and file name for
the new file to be saved.
-
cancel
event (
Event.CANCEL
):
Dispatched when the user click the Cancel button in the dialog box.
-
open
event (
Event.OPEN
):
Dispatched when the save operation starts.
-
progress
event (
ProgressEvent.PROGRESS
):
Dispatched periodically as bytes of data are saved to the file.
-
complete
event (
Event.COMPLETE
):
Dispatched when the save operation completes successfully.
-
ioError
event (
IOErrorEvent.IO_ERROR
):
Dispatched if the saving process fails because an input/output error
occurs while attempting to save data to the file.
The type of object passed in the
data
parameter
of the
FileReference.save()
method determines how the
data is written to the file:
-
If it is a String value, then it is saved as a text file
using UTF-8 encoding.
-
If it is an XML object, then it is written to a file in XML
format with all formatting preserved.
-
If it is a ByteArray object, then its contents are written
directly to the file with no conversion.
-
If it is some other object, then the
FileReference.save()
method
calls the object’s
toString()
method and then saves
the resulting String value to a UTF-8 text file. If the object’s
toString()
method
can’t be called, then an error is thrown.
If the value of the
data
parameter is
null
,
then an error is thrown.
The following code extends the previous example for the
FileReference.load()
method.
After reading the data from the file, this example prompts the user
for a filename and then saves the data in a new file:
package
{
import flash.display.Sprite;
import flash.events.*;
import flash.net.FileFilter;
import flash.net.FileReference;
import flash.net.URLRequest;
import flash.utils.ByteArray;
public class FileReferenceExample2 extends Sprite
{
private var fileRef:FileReference;
public function FileReferenceExample2()
{
fileRef = new FileReference();
fileRef.addEventListener(Event.SELECT, onFileSelected);
fileRef.addEventListener(Event.CANCEL, onCancel);
fileRef.addEventListener(IOErrorEvent.IO_ERROR, onIOError);
fileRef.addEventListener(SecurityErrorEvent.SECURITY_ERROR,
onSecurityError);
var textTypeFilter:FileFilter = new FileFilter("Text Files (*.txt, *.rtf)",
"*.txt;*.rtf");
fileRef.browse([textTypeFilter]);
}
public function onFileSelected(evt:Event):void
{
fileRef.addEventListener(ProgressEvent.PROGRESS, onProgress);
fileRef.addEventListener(Event.COMPLETE, onComplete);
fileRef.load();
}
public function onProgress(evt:ProgressEvent):void
{
trace("Loaded " + evt.bytesLoaded + " of " + evt.bytesTotal + " bytes.");
}
public function onCancel(evt:Event):void
{
trace("The browse request was canceled by the user.");
}
public function onComplete(evt:Event):void
{
trace("File was successfully loaded.");
fileRef.removeEventListener(Event.SELECT, onFileSelected);
fileRef.removeEventListener(ProgressEvent.PROGRESS, onProgress);
fileRef.removeEventListener(Event.COMPLETE, onComplete);
fileRef.removeEventListener(Event.CANCEL, onCancel);
saveFile();
}
public function saveFile():void
{
fileRef.addEventListener(Event.SELECT, onSaveFileSelected);
fileRef.save(fileRef.data,"NewFileName.txt");
}
public function onSaveFileSelected(evt:Event):void
{
fileRef.addEventListener(ProgressEvent.PROGRESS, onSaveProgress);
fileRef.addEventListener(Event.COMPLETE, onSaveComplete);
fileRef.addEventListener(Event.CANCEL, onSaveCancel);
}
public function onSaveProgress(evt:ProgressEvent):void
{
trace("Saved " + evt.bytesLoaded + " of " + evt.bytesTotal + " bytes.");
}
public function onSaveComplete(evt:Event):void
{
trace("File saved.");
fileRef.removeEventListener(Event.SELECT, onSaveFileSelected);
fileRef.removeEventListener(ProgressEvent.PROGRESS, onSaveProgress);
fileRef.removeEventListener(Event.COMPLETE, onSaveComplete);
fileRef.removeEventListener(Event.CANCEL, onSaveCancel);
}
public function onSaveCancel(evt:Event):void
{
trace("The save request was canceled by the user.");
}
public function onIOError(evt:IOErrorEvent):void
{
trace("There was an IO Error.");
}
public function onSecurityError(evt:Event):void
{
trace("There was a security error.");
}
}
}
When all of the data loads from the file, the code calls the
onComplete()
method.
The
onComplete()
method removes the listeners for
the loading events and then calls the
saveFile()
method. The
saveFile()
method
calls the
FileReference.save()
method. The
FileReference.save()
method
opens a new dialog box to let the user enter a new filename and
location to save the file. The remaining event listener methods
trace the progress of the file saving process until it is complete.
In Adobe AIR, the FileStream class provides additional functionality
for writing data to a local file. See
Reading and writing files
.
Uploading files to a server
To upload files
to a server, first call the
browse()
method to
allow a user to select one or more files. Next, when the
FileReference.upload()
method
is called, the selected file is transferred to the server. If the
user selects multiple files using the
FileReferenceList.browse()
method,
Flash Player creates an array of selected files called
FileReferenceList.fileList
.
You can then use the
FileReference.upload()
method
to upload each file individually.
Note:
Using the
FileReference.browse()
method
allows you to upload single files only. To allow a user to upload
multiple files, use the
FileReferenceList.browse()
method.
By default, the system file picker dialog box allows users to
pick any file type from the local computer. Developers can specify
one or more custom file type filters by using the FileFilter class
and passing an array of file filter instances to the
browse()
method:
var imageTypes:FileFilter = new FileFilter("Images (*.jpg, *.jpeg, *.gif, *.png)", "*.jpg; *.jpeg; *.gif; *.png");
var textTypes:FileFilter = new FileFilter("Text Files (*.txt, *.rtf)", "*.txt; *.rtf");
var allTypes:Array = new Array(imageTypes, textTypes);
var fileRef:FileReference = new FileReference();
fileRef.browse(allTypes);
When the user has selected the files and clicked the Open button
in the system file picker, the
Event.SELECT
event
is dispatched. If the
FileReference.browse()
method is
used to select a file to upload, the following code sends the file
to a web server:
var fileRef:FileReference = new FileReference();
fileRef.addEventListener(Event.SELECT, selectHandler);
fileRef.addEventListener(Event.COMPLETE, completeHandler);
try
{
var success:Boolean = fileRef.browse();
}
catch (error:Error)
{
trace("Unable to browse for files.");
}
function selectHandler(event:Event):void
{
var request:URLRequest = new URLRequest("http://www.[yourdomain].com/fileUploadScript.cfm")
try
{
fileRef.upload(request);
}
catch (error:Error)
{
trace("Unable to upload file.");
}
}
function completeHandler(event:Event):void
{
trace("uploaded");
}
You can send data to the server with the
FileReference.upload()
method
by using the
URLRequest.method
and
URLRequest.data
properties
to send variables using the
POST
or
GET
methods.
When you attempt to upload a file using the
FileReference.upload()
method,
the following events are dispatched:
-
open
event (
Event.OPEN
):
Dispatched when the upload operation starts.
-
progress
event (
ProgressEvent.PROGRESS
):
Dispatched periodically as bytes of data from the file are uploaded.
-
complete
event (
Event.COMPLETE
):
Dispatched when the upload operation completes successfully.
-
httpStatus
event (
HTTPStatusEvent.HTTP_STATUS
):
Dispatched when the upload process fails because of an HTTP error.
-
httpResponseStatus
event (
HTTPStatusEvent.HTTP_RESPONSE_STATUS
): Dispatched
if a call to the
upload()
or
uploadUnencoded()
method
attempts to access data over HTTP and Adobe AIR is able to detect
and return the status code for the request.
-
securityError
event (
SecurityErrorEvent.SECURITY_ERROR
): Dispatched
when an upload operation fails because of a security violation.
-
uploadCompleteData
event (
DataEvent.UPLOAD_COMPLETE_DATA
): Dispatched
after data is received from the server after a successful upload.
-
ioError
event (
IOErrorEvent.IO_ERROR
):
Dispatched if the upload process fails for any of the following
reasons:
-
An input/output error occurred while Flash
Player is reading, writing, or transmitting the file.
-
The SWF tried to upload a file to a server that requires
authentication (such as a user name and password). During upload,
Flash Player does not provide a means for users to enter passwords.
-
The
url
parameter contains an invalid protocol.
The
FileReference.upload()
method must use either
HTTP or HTTPS.
Flash Player does not offer complete support
for servers that require authentication. Only SWF files that are
running in a browser using the browser plug-in or Microsoft ActiveX® control can provide a dialog box to prompt
the user to enter a user name and password for authentication, and
then only for downloads. For uploads using the plug-in or ActiveX
control or upload/download using either the stand-alone or external
player, the file transfer fails.
To create a server script in ColdFusion to accept a file upload
from Flash Player, you can use code similar to the following:
<cffile action="upload" filefield="Filedata" destination="#ExpandPath('./')#" nameconflict="OVERWRITE" />
This ColdFusion code uploads the file sent by Flash Player and
saves it to the same directory as the ColdFusion template, overwriting
any file with the same name. The previous code shows the bare minimum
amount of code necessary to accept a file upload; this script should
not be used in a production environment. Ideally, add data validation
to ensure that users upload only accepted file types, such as an
image instead of a potentially dangerous server-side script.
The following code demonstrates file uploads using PHP, and it
includes data validation. The script limits the number of uploaded
files in the upload directory to 10, ensures that the file is less
than 200 KB, and permits only JPEG, GIF, or PNG files to be uploaded
and saved to the file system.
<?php
$MAXIMUM_FILESIZE = 1024 * 200; // 200KB
$MAXIMUM_FILE_COUNT = 10; // keep maximum 10 files on server
echo exif_imagetype($_FILES['Filedata']);
if ($_FILES['Filedata']['size'] <= $MAXIMUM_FILESIZE)
{
move_uploaded_file($_FILES['Filedata']['tmp_name'], "./temporary/".$_FILES['Filedata']['name']);
$type = exif_imagetype("./temporary/".$_FILES['Filedata']['name']);
if ($type == 1 || $type == 2 || $type == 3)
{
rename("./temporary/".$_FILES['Filedata']['name'], "./images/".$_FILES['Filedata']['name']);
}
else
{
unlink("./temporary/".$_FILES['Filedata']['name']);
}
}
$directory = opendir('./images/');
$files = array();
while ($file = readdir($directory))
{
array_push($files, array('./images/'.$file, filectime('./images/'.$file)));
}
usort($files, sorter);
if (count($files) > $MAXIMUM_FILE_COUNT)
{
$files_to_delete = array_splice($files, 0, count($files) - $MAXIMUM_FILE_COUNT);
for ($i = 0; $i < count($files_to_delete); $i++)
{
unlink($files_to_delete[$i][0]);
}
}
print_r($files);
closedir($directory);
function sorter($a, $b)
{
if ($a[1] == $b[1])
{
return 0;
}
else
{
return ($a[1] < $b[1]) ? -1 : 1;
}
}
?>
You can pass additional variables to the upload script using
either the
POST
or
GET
request
method. To send additional
POST
variables to your
upload script, you can use the following code:
var fileRef:FileReference = new FileReference();
fileRef.addEventListener(Event.SELECT, selectHandler);
fileRef.addEventListener(Event.COMPLETE, completeHandler);
fileRef.browse();
function selectHandler(event:Event):void
{
var params:URLVariables = new URLVariables();
params.date = new Date();
params.ssid = "94103-1394-2345";
var request:URLRequest = new URLRequest("http://www.yourdomain.com/FileReferenceUpload/fileupload.cfm");
request.method = URLRequestMethod.POST;
request.data = params;
fileRef.upload(request, "Custom1");
}
function completeHandler(event:Event):void
{
trace("uploaded");
}
The previous example creates a URLVariables object that you pass
to the remote server- side script. In previous versions of ActionScript,
you could pass variables to the server upload script by passing
values in the query string. ActionScript 3.0 allows you to pass
variables to the remote script using a URLRequest object, which
allows you to pass data using either the
POST
or
GET
method;
this, in turn, makes passing larger sets of data easier and cleaner.
In order to specify whether the variables are passed using the
GET
or
POST
request
method, you can set the
URLRequest.method
property
to either
URLRequestMethod.GET
or
URLRequestMethod.POST
,
respectively.
ActionScript 3.0 also lets you override the default
Filedata
upload
file field name by providing a second parameter to the
upload()
method,
as demonstrated in the previous example (which replaced the default
value
Filedata
with
Custom1
).
By default, Flash Player does not attempt to send a test upload,
although you can override this default by passing a value of
true
as
the third parameter to the
upload()
method. The
purpose of the test upload is to check whether the actual file upload
will be successful and that server authentication, if required,
will succeed.
Note:
A test upload occurs only on Windows-based Flash
Players at this time.
The server script that handles the file upload should expect
an HTTP
POST
request with the following elements:
-
Content-Type
with a value of
multipart/form-data.
-
Content-Disposition
with a
name
attribute
set to “
Filedata
” and a
filename
attribute
set to the name of the original file. You can specify a custom
name
attribute
by passing a value for the
uploadDataFieldName
parameter
in the
FileReference.upload()
method.
-
The binary contents of the file.
Here is a sample HTTP
POST
request:
POST /handler.asp HTTP/1.1
Accept: text/*
Content-Type: multipart/form-data;
boundary=----------Ij5ae0ae0KM7GI3KM7ei4cH2ei4gL6
User-Agent: Shockwave Flash
Host: www.mydomain.com
Content-Length: 421
Connection: Keep-Alive
Cache-Control: no-cache
------------Ij5ae0ae0KM7GI3KM7ei4cH2ei4gL6
Content-Disposition: form-data; name="Filename"
sushi.jpg
------------Ij5ae0ae0KM7GI3KM7ei4cH2ei4gL6
Content-Disposition: form-data; name="Filedata"; filename="sushi.jpg"
Content-Type: application/octet-stream
Test File
------------Ij5ae0ae0KM7GI3KM7ei4cH2ei4gL6
Content-Disposition: form-data; name="Upload"
Submit Query
------------Ij5ae0ae0KM7GI3KM7ei4cH2ei4gL6
(actual file data,,,)
The following sample HTTP
POST
request sends
three
POST
variables:
api_sig
,
api_key
,
and
auth_token
, and uses a custom upload data field
name value of
"photo"
:
POST /handler.asp HTTP/1.1
Accept: text/*
Content-Type: multipart/form-data;
boundary=----------Ij5ae0ae0KM7GI3KM7ei4cH2ei4gL6
User-Agent: Shockwave Flash
Host: www.mydomain.com
Content-Length: 421
Connection: Keep-Alive
Cache-Control: no-cache
------------Ij5GI3GI3ei4GI3ei4KM7GI3KM7KM7
Content-Disposition: form-data; name="Filename"
sushi.jpg
------------Ij5GI3GI3ei4GI3ei4KM7GI3KM7KM7
Content-Disposition: form-data; name="api_sig"
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
------------Ij5GI3GI3ei4GI3ei4KM7GI3KM7KM7
Content-Disposition: form-data; name="api_key"
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
------------Ij5GI3GI3ei4GI3ei4KM7GI3KM7KM7
Content-Disposition: form-data; name="auth_token"
XXXXXXXXXXXXXXXXXXXXXXX
------------Ij5GI3GI3ei4GI3ei4KM7GI3KM7KM7
Content-Disposition: form-data; name="photo"; filename="sushi.jpg"
Content-Type: application/octet-stream
(actual file data,,,)
------------Ij5GI3GI3ei4GI3ei4KM7GI3KM7KM7
Content-Disposition: form-data; name="Upload"
Submit Query
------------Ij5GI3GI3ei4GI3ei4KM7GI3KM7KM7--
Downloading files from a server
You can let
users download files from a server using the
FileReference.download()
method,
which takes two parameters:
request
and
defaultFileName
.
The first parameter is the URLRequest object that contains the URL
of the file to download. The second parameter is optional—it lets
you specify a default filename that appears in the download file
dialog box. If you omit the second parameter,
defaultFileName
,
the filename from the specified URL is used.
The following code downloads a file named index.xml from the
same directory as the SWF file:
var request:URLRequest = new URLRequest("index.xml");
var fileRef:FileReference = new FileReference();
fileRef.download(request);
To set the default name to currentnews.xml instead of index.xml,
specify the
defaultFileName
parameter, as the following
snippet shows:
var request:URLRequest = new URLRequest("index.xml");
var fileToDownload:FileReference = new FileReference();
fileToDownload.download(request, "currentnews.xml");
Renaming a file can be useful if the server filename was not
intuitive or was server-generated. It’s also good to explicitly
specify the
defaultFileName
parameter when you
download a file using a server-side script, instead of downloading
the file directly. For example, you need to specify the
defaultFileName
parameter
if you have a server-side script that downloads specific files based
on URL variables passed to it. Otherwise, the default name of the
downloaded file is the name of your server-side script.
Data can be sent to the server using the
download()
method
by appending parameters to the URL for the server script to parse.
The following ActionScript 3.0 snippet downloads a document based
on which parameters are passed to a ColdFusion script:
package
{
import flash.display.Sprite;
import flash.net.FileReference;
import flash.net.URLRequest;
import flash.net.URLRequestMethod;
import flash.net.URLVariables;
public class DownloadFileExample extends Sprite
{
private var fileToDownload:FileReference;
public function DownloadFileExample()
{
var request:URLRequest = new URLRequest();
request.url = "http://www.[yourdomain].com/downloadfile.cfm";
request.method = URLRequestMethod.GET;
request.data = new URLVariables("id=2");
fileToDownload = new FileReference();
try
{
fileToDownload.download(request, "file2.txt");
}
catch (error:Error)
{
trace("Unable to download file.");
}
}
}
}
The following code demonstrates the ColdFusion script, download.cfm,
that downloads one of two files from the server, depending on the
value of a URL variable:
<cfparam name="URL.id" default="1" />
<cfswitch expression="#URL.id#">
<cfcase value="2">
<cfcontent type="text/plain" file="#ExpandPath('two.txt')#" deletefile="No" />
</cfcase>
<cfdefaultcase>
<cfcontent type="text/plain" file="#ExpandPath('one.txt')#" deletefile="No" />
</cfdefaultcase>
</cfswitch>
FileReferenceList class
The
FileReferenceList class lets the user select one or more files to
upload to a server-side script. The file upload is handled by the
FileReference.upload()
method,
which must be called on each file that the user selects.
The following code creates two FileFilter objects (
imageFilter
and
textFilter
) and
passes them in an array to the
FileReferenceList.browse()
method.
This causes the operating system file dialog box to display two
possible filters for file types.
var imageFilter:FileFilter = new FileFilter("Image Files (*.jpg, *.jpeg, *.gif, *.png)", "*.jpg; *.jpeg; *.gif; *.png");
var textFilter:FileFilter = new FileFilter("Text Files (*.txt, *.rtf)", "*.txt; *.rtf");
var fileRefList:FileReferenceList = new FileReferenceList();
try
{
var success:Boolean = fileRefList.browse(new Array(imageFilter, textFilter));
}
catch (error:Error)
{
trace("Unable to browse for files.");
}
Allowing the user to select and upload one or more files by using
the FileReferenceList class is the same as using
FileReference.browse()
to
select files, although the FileReferenceList allows you to select
more than one file. Uploading multiple files requires you to upload
each of the selected files by using
FileReference.upload()
,
as the following code shows:
var fileRefList:FileReferenceList = new FileReferenceList();
fileRefList.addEventListener(Event.SELECT, selectHandler);
fileRefList.browse();
function selectHandler(event:Event):void
{
var request:URLRequest = new URLRequest("http://www.[yourdomain].com/fileUploadScript.cfm");
var file:FileReference;
var files:FileReferenceList = FileReferenceList(event.target);
var selectedFileArray:Array = files.fileList;
for (var i:uint = 0; i < selectedFileArray.length; i++)
{
file = FileReference(selectedFileArray[i]);
file.addEventListener(Event.COMPLETE, completeHandler);
try
{
file.upload(request);
}
catch (error:Error)
{
trace("Unable to upload files.");
}
}
}
function completeHandler(event:Event):void
{
trace("uploaded");
}
Because the
Event.COMPLETE
event is added to each
individual FileReference object in the array, Flash Player calls
the
completeHandler()
method when each individual
file finishes uploading.
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