tcaudilllg
Dragonmaster
Joined: 20 Jun 2002
Posts: 1731
Location: Cedar Bluff, VA
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 Posted: Mon Aug 09, 2010 4:16 pm Post subject: How to read/write files in Firefox. |
[quote] |
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I don't have to mention how awesome the topic of this post is, so I won't.
The first step is to get the necessary permissions from Firefox. You do this by interfacing with XPCOM, Mozilla's answer to Microsoft's COM. ("Component Object Model")
| Code: |
this.netscape.security.PrivilegeManager.enablePrivilege('UniversalXPConnect');
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Sometimes you have to change a flag in about:config first, depending on whether or not you've previously locked down your Firefox install. Oh, and deactivate NoScript while you're at it.
Firefox read/write is definitely NSFW -- you could be fired if a security compromise caused by read/write permissions is found to have originated on your terminal.
Without further ado, the code.
| Code: |
<html>
<head>
<script>
// IO.JS - file input/output for Firefox
// ...And every bit of it ripped from MDC's examples. Seriously though, I don't think they could have made it any more complicated. :P
this.netscape.security.PrivilegeManager.enablePrivilege('UniversalXPConnect');
function writeFile (fileData, filePath)
{
// "fileData" is a string containing the data to write. "filePath" is a string containing the complete path for the file.
// This function writes a string to a file, erasing its previous content.
var file = Components.classes["@mozilla.org/file/local;1"]
.createInstance(Components.interfaces.nsILocalFile);
file.initWithPath( filePath );
file.createUnique( Components.interfaces.nsIFile.NORMAL_FILE_TYPE, 600);
var stream = Components.classes["@mozilla.org/network/safe-file-output-stream;1"]
.createInstance(Components.interfaces.nsIFileOutputStream);
stream.init(file, 0x04 | 0x08 | 0x20, 0600, 0); // readwrite, create, truncate
stream.write(fileData, fileData.length);
if (stream instanceof Components.interfaces.nsISafeOutputStream) {
stream.finish();
} else {
stream.close();
}
}
function readFile (filePath)
{
// "filePath" is a string containing the complete path of the file to be read.
// This function returns a string containing the data of the read file.
var file = filePath;
var incoming = Components.classes["@mozilla.org/network/file-input-stream;1"]
.createInstance(Components.interfaces.nsIFileInputStream);
incoming.init(file, -1, -1, false);
var cache = Components.classes["@mozilla.org/binaryinputstream;1"]
.createInstance(Components.interfaces.nsIBinaryInputStream);
cache.setInputStream(incoming);
return cache.readBytes(cache.available());
}
function saveFile (fileData, filter)
{
// "fileData" is a string containing the data to write. "filter" is the file's default extension.
// This function allows the user to save a file with the save-as dialogue box.
// This first segment allows that a file be picked with the open/save dialogue window.
const nsIFilePicker = Components.interfaces.nsIFilePicker;
var filePicker = Components.classes["@mozilla.org/filepicker;1"].createInstance(nsIFilePicker);
filePicker.init(window, "", nsIFilePicker.modeSave);
if (filter == "")
{
filePicker.appendFilters(nsIFilePicker.filterAll);
}
else
{
filePicker.appendFilter("*." + filter, "*." + filter);
}
var selection = filePicker.show();
if (selection == nsIFilePicker.returnOK || selection == nsIFilePicker.returnReplace)
{
// This is the actual code to write the file.
var file = Components.classes["@mozilla.org/file/local;1"]
.createInstance(Components.interfaces.nsILocalFile);
file.initWithPath( filePicker.file.path );
file.createUnique( Components.interfaces.nsIFile.NORMAL_FILE_TYPE, 600);
var stream = Components.classes["@mozilla.org/network/safe-file-output-stream;1"]
.createInstance(Components.interfaces.nsIFileOutputStream);
stream.init(file, 0x04 | 0x08 | 0x20, 0600, 0); // readwrite, create, truncate
stream.write(fileData, fileData.length);
if (stream instanceof Components.interfaces.nsISafeOutputStream) {
stream.finish();
} else {
stream.close();
}
}
}
function openFile (filter)
{
// "filter" is a string specifying which files extensions to show in the open dialogue box.
// This function allows the user to open a file with the open dialogue box. It returns a string with the file's contents.
// This first segment allows that a file be picked with the open/save dialogue window.
this.netscape.security.PrivilegeManager.enablePrivilege('UniversalXPConnect');
const nsIFilePicker = Components.interfaces.nsIFilePicker;
var filePicker = Components.classes["@mozilla.org/filepicker;1"].createInstance(nsIFilePicker);
filePicker.init(window, "", nsIFilePicker.modeOpen);
if (filter == "")
{
filePicker.appendFilters(nsIFilePicker.filterAll);
}
else
{
filePicker.appendFilter("*." + filter, "*." + filter);
}
var selection = filePicker.show();
if (selection == nsIFilePicker.returnOK || selection == nsIFilePicker.returnReplace)
{
// This is the actual code to read the file.
var file = filePicker.file;
var incoming = Components.classes["@mozilla.org/network/file-input-stream;1"]
.createInstance(Components.interfaces.nsIFileInputStream);
incoming.init(file, -1, -1, false);
var cache = Components.classes["@mozilla.org/binaryinputstream;1"]
.createInstance(Components.interfaces.nsIBinaryInputStream);
cache.setInputStream(incoming);
return cache.readBytes(cache.available());
}
}
</script>
</head>
<textarea></textarea>
<input>
<input>
</html>
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Users may be asked to affirm whether they want to allow your script access to their file system. Obviously, you want them to click "yes".
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