mirror of https://github.com/rwf2/Rocket.git
46 lines
1.5 KiB
Rust
46 lines
1.5 KiB
Rust
use std::borrow::Cow;
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use std::path::{Path, PathBuf};
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use rand::{self, Rng};
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use rocket::request::FromParam;
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/// A _probably_ unique paste ID.
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#[derive(UriDisplayPath)]
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pub struct PasteId<'a>(Cow<'a, str>);
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impl PasteId<'_> {
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/// Generate a _probably_ unique ID with `size` characters. For readability,
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/// the characters used are from the sets [0-9], [A-Z], [a-z]. The
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/// probability of a collision depends on the value of `size` and the number
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/// of IDs generated thus far.
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pub fn new(size: usize) -> PasteId<'static> {
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const BASE62: &[u8] = b"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
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let mut id = String::with_capacity(size);
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let mut rng = rand::thread_rng();
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for _ in 0..size {
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id.push(BASE62[rng.gen::<usize>() % 62] as char);
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}
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PasteId(Cow::Owned(id))
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}
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/// Returns the path to the paste in `upload/` corresponding to this ID.
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pub fn file_path(&self) -> PathBuf {
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let root = concat!(env!("CARGO_MANIFEST_DIR"), "/", "upload");
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Path::new(root).join(self.0.as_ref())
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}
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}
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/// Returns an instance of `PasteId` if the path segment is a valid ID.
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/// Otherwise returns the invalid ID as the `Err` value.
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impl<'a> FromParam<'a> for PasteId<'a> {
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type Error = &'a str;
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fn from_param(param: &'a str) -> Result<Self, Self::Error> {
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param.chars().all(|c| c.is_ascii_alphanumeric())
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.then(|| PasteId(param.into()))
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.ok_or(param)
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}
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}
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