rust create a String from file.read_to_end()

Question

I am trying to read a file and return it as a UTF-8 std:string:String it seems like content is a Result<collections::string::String, collections::vec::Vec<u8>> if i understand an error message i got from trying String::from_utf8(content).

fn get_index_body () -> String {
    let path = Path::new("../html/ws1.html");
    let display = path.display();
    let mut file = match File::open(&path) {
        Ok(f) => f,
        Err(err) => panic!("file error: {}", err)
    };

    let content = file.read_to_end();
    println!("{} {}", display, content);

    return String::new(); // how to turn into String (which is utf-8)
}

Answer 1

Check the functions provided by the io::Reader trait: https://doc.rust-lang.org/std/io/trait.Read.html

read_to_end() returns IoResult<Vec<u8>>, read_to_string() returns IoResult<String>.

IoResult<String> is just a handy way to write Result<String, IoError>: https://doc.rust-lang.org/std/io/type.Result.html

You can extract Strings from a Result either using unwrap():

let content = file.read_to_end();
content.unwrap()

or by handling the error yourself:

let content = file.read_to_end();
match content {
    Ok(s) => s,
    Err(why) => panic!("{}", why)
}

See also: http://doc.rust-lang.org/std/result/enum.Result.html