112 lines
4.8 KiB
Markdown
112 lines
4.8 KiB
Markdown
IDBFS is provides a POSIX-like file system interface for browser-based JavaScript.
|
|
|
|
* [idbfs.js](https://raw.github.com/js-platform/idbfs/develop/dist/idbfs.js)
|
|
* [idbfs.min.js](https://raw.github.com/js-platform/idbfs/develop/dist/idbfs.min.js)
|
|
|
|
### Getting Started
|
|
|
|
IDBFS is partly based on the `fs` module from node.js. The API is asynchronous and most methods require the caller to provide a callback function. Errors are passed to callbacks through the first parameter.
|
|
|
|
To create a new file system or open an existing one, create a new `FileSystem` instance and pass the name of the file system. A new IndexedDB database is created for each file system.
|
|
|
|
#### Example
|
|
|
|
````
|
|
<script>
|
|
var fs = new IDBFS.FileSystem('local');
|
|
fs.open('/myfile', 'w+', function(err, fd) {
|
|
if (err) throw err;
|
|
fs.close(fd, function(err) {
|
|
if (err) throw err;
|
|
fs.stat('/myfile', function(err, stats) {
|
|
if (err) throw err;
|
|
console.log('stats: ' + JSON.stringify(stats));
|
|
});
|
|
});
|
|
});
|
|
</script>
|
|
````
|
|
|
|
As with node.js, there is no guarantee that file system operations will be executed in the order they are invoked. Ensure proper ordering by chaining operations in callbacks.
|
|
|
|
### API Reference
|
|
|
|
Callbacks for methods that accept them are non-optional. The first callback parameter is reserved for passing errors. It will be `undefined` if no errors occurred and should always be checked.
|
|
|
|
#### IDBFS.FileSystem(name, flags)
|
|
|
|
File system constructor, invoked to open an existing file system or create a new one. Accepts a name and optional flags. Use `'FORMAT'` to force IDBFS for format the file system.
|
|
|
|
#### fs.stat(path, callback)
|
|
|
|
Asynchronous stat(2). Callback gets `(error, stats)`, where `stats` is an object like
|
|
|
|
{
|
|
node: <string> // internal node id (unique)
|
|
dev: <string> // file system name
|
|
size: <number> // file size in bytes
|
|
nlinks: <number> // number of links
|
|
atime: <number> // last access time
|
|
mtime: <number> // last modified time
|
|
ctime: <number> // creation time
|
|
type: <string> // file type (FILE, DIRECTORY, ...)
|
|
}
|
|
|
|
#### fs.fstat(fd, callback)
|
|
|
|
Asynchronous stat(2). Callback gets `(error, stats)`. See `fs.stat`.
|
|
|
|
#### fs.link(oldpath, newpath, callback)
|
|
|
|
Asynchronous link(2). Callback gets no additional agruments.
|
|
|
|
#### fs.unlink(path, callback)
|
|
|
|
Asynchronous unlink(2). Callback gets no additional agruments.
|
|
|
|
#### fs.rmdir(path, callback)
|
|
|
|
Asynchronous rmdir(2). Callback gets no additional agruments.
|
|
|
|
#### fs.mkdir(path, callback)
|
|
|
|
Asynchronous mkdir(2). Callback gets no additional agruments.
|
|
|
|
#### fs.close(fd, callback)
|
|
|
|
Asynchronous close(2). Callback gets no additional agruments.
|
|
|
|
#### fs.open(path, flags, callback)
|
|
|
|
Asynchronous open(2). Flags can be
|
|
|
|
* `'r'`: Open file for reading. An exception occurs if the file does not exist.
|
|
* `'r+'`: Open file for reading and writing. An exception occurs if the file does not exist.
|
|
* `'w'`: Open file for writing. The file is created (if it does not exist) or truncated (if it exists).
|
|
* `'w+'`: Open file for reading and writing. The file is created (if it does not exist) or truncated (if it exists).
|
|
* `'a'`: Open file for appending. The file is created if it does not exist.
|
|
* `'a+'`: Open file for reading and appending. The file is created if it does not exist.
|
|
|
|
Callback gets `(error, fd)`, where `fd` is the file descriptor.
|
|
|
|
Unlike node.js, IDBFS does not accept the optional `mode` parameter since it doesn't yet implement file permissions.
|
|
|
|
#### fs.write(fd, buffer, offset, length, position, callback)
|
|
|
|
Write bytes from `buffer` to the file specified by `fd`, where `offset` and `length` describe the part of the buffer to be written. The `position` refers to the offset from the beginning of the file where this data should be written. If `position` is `null`, the data will be written at the current position. See pwrite(2).
|
|
|
|
The callback gets `(error, nbytes)`, where `nbytes` is the number of bytes written.
|
|
|
|
#### fs.read(fd, buffer, offset, length, position, callback)
|
|
|
|
Read bytes from the file specified by `fd` into `buffer`, where `offset` and `length` describe the part of the buffer to be used. The `position` refers to the offset from the beginning of the file where this data should be read. If `position` is `null`, the data will be written at the current position. See pread(2).
|
|
|
|
The callback gets `(error, nbytes)`, where `nbytes` is the number of bytes read.
|
|
|
|
#### fs.lseek(fd, offset, whence, callback)
|
|
|
|
Asynchronous lseek(2), where `whence` can be `SET`, `CUR`, or `END`. Callback gets `(error, pos)`, where `pos` is the resulting offset, in bytes, from the beginning of the file.
|
|
|
|
#### fs.readdir(path, callback)
|
|
|
|
Asynchronous readdir(3). Reads the contents of a directory. Callback gets `(error, files)`, where `files` is an array containing the names of each file in the directory, excluding `.` and `..`. |