Attempts to open a file in read-only mode.

Errors

This function will return an error if path does not already exist. Other errors may also be returned according to OpenOptions::open.

Examples

use rocket::response::NamedFile;

let file = NamedFile::open("foo.txt");

Retrieve the underlying File.

Take the underlying File.

Retrieve a mutable borrow to the underlying File.

Retrieve the path of this file.

Examples

use rocket::response::NamedFile;

let file = NamedFile::open("foo.txt")?;
assert_eq!(file.path().as_os_str(), "foo.txt");

Attempts to sync all OS-internal metadata to disk.

This function will attempt to ensure that all in-core data reaches the filesystem before returning.

Examples

use std::fs::File;
use std::io::prelude::*;

let mut f = File::create("foo.txt")?;
f.write_all(b"Hello, world!")?;

f.sync_all()?;

This function is similar to sync_all, except that it may not synchronize file metadata to the filesystem.

This is intended for use cases that must synchronize content, but don't need the metadata on disk. The goal of this method is to reduce disk operations.

Note that some platforms may simply implement this in terms of sync_all.

Examples

use std::fs::File;
use std::io::prelude::*;

let mut f = File::create("foo.txt")?;
f.write_all(b"Hello, world!")?;

f.sync_data()?;

Truncates or extends the underlying file, updating the size of this file to become size.

If the size is less than the current file's size, then the file will be shrunk. If it is greater than the current file's size, then the file will be extended to size and have all of the intermediate data filled in with 0s.

Errors

This function will return an error if the file is not opened for writing.

Examples

use std::fs::File;

let mut f = File::create("foo.txt")?;
f.set_len(10)?;

Note that this method alters the content of the underlying file, even though it takes &self rather than &mut self.

Queries metadata about the underlying file.

Examples

use std::fs::File;

let mut f = File::open("foo.txt")?;
let metadata = f.metadata()?;

Create a new File instance that shares the same underlying file handle as the existing File instance. Reads, writes, and seeks will affect both File instances simultaneously.

Examples

Create two handles for a file named foo.txt:

use std::fs::File;

let mut file = File::open("foo.txt")?;
let file_copy = file.try_clone()?;

Assuming there’s a file named foo.txt with contents abcdef\n, create two handles, seek one of them, and read the remaining bytes from the other handle:

use std::fs::File;
use std::io::SeekFrom;
use std::io::prelude::*;

let mut file = File::open("foo.txt")?;
let mut file_copy = file.try_clone()?;

file.seek(SeekFrom::Start(3))?;

let mut contents = vec![];
file_copy.read_to_end(&mut contents)?;
assert_eq!(contents, b"def\n");

Changes the permissions on the underlying file.

Platform-specific behavior

This function currently corresponds to the fchmod function on Unix and the SetFileInformationByHandle function on Windows. Note that, this may change in the future.

Errors

This function will return an error if the user lacks permission change attributes on the underlying file. It may also return an error in other os-specific unspecified cases.

Examples

use std::fs::File;

let file = File::open("foo.txt")?;
let mut perms = file.metadata()?.permissions();
perms.set_readonly(true);
file.set_permissions(perms)?;

Note that this method alters the permissions of the underlying file, even though it takes &self rather than &mut self.