Rocket/examples/pastebin/src/paste_id.rs

56 lines
1.7 KiB
Rust

use std::borrow::Cow;
use std::path::{Path, PathBuf};
use rocket::http::uri::{self, FromUriParam};
use rocket::request::FromParam;
use rand::{self, Rng};
/// Table to retrieve base62 values from.
const BASE62: &[u8] = b"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
/// A _probably_ unique paste ID.
#[derive(UriDisplayPath)]
pub struct PasteId<'a>(Cow<'a, str>);
impl PasteId<'_> {
/// Generate a _probably_ unique ID with `size` characters. For readability,
/// the characters used are from the sets [0-9], [A-Z], [a-z]. The
/// probability of a collision depends on the value of `size` and the number
/// of IDs generated thus far.
pub fn new(size: usize) -> PasteId<'static> {
let mut id = String::with_capacity(size);
let mut rng = rand::thread_rng();
for _ in 0..size {
id.push(BASE62[rng.gen::<usize>() % 62] as char);
}
PasteId(Cow::Owned(id))
}
pub fn file_path(&self) -> PathBuf {
let root = concat!(env!("CARGO_MANIFEST_DIR"), "/", "upload");
Path::new(root).join(self.0.as_ref())
}
}
/// Returns an instance of `PasteId` if the path segment is a valid ID.
/// Otherwise returns the invalid ID as the `Err` value.
impl<'a> FromParam<'a> for PasteId<'a> {
type Error = &'a str;
fn from_param(param: &'a str) -> Result<Self, Self::Error> {
match param.chars().all(|c| c.is_ascii_alphanumeric()) {
true => Ok(PasteId(param.into())),
false => Err(param)
}
}
}
impl<'a> FromUriParam<uri::Path, &'a str> for PasteId<'_> {
type Target = PasteId<'a>;
fn from_uri_param(param: &'a str) -> Self::Target {
PasteId(param.into())
}
}