chir.rs/chir-rs-db/src/file.rs

252 lines
8.1 KiB
Rust

//! File related APIs
use std::fmt::Formatter;
use bincode::{error::DecodeError, Decode, Encode};
use blake3::Hash;
use eyre::Context as _;
use eyre::Result;
use mime::Mime;
use serde::{de::Visitor, Deserialize, Deserializer, Serialize, Serializer};
use sqlx::{postgres::PgRow, prelude::FromRow, query_as};
use sqlx::{query, Row as _};
use tracing::instrument;
use crate::Database;
/// Serializes a mime type to string
fn serialize_mime<S: Serializer>(mime: &Mime, s: S) -> Result<S::Ok, S::Error> {
s.serialize_str(mime.as_ref())
}
/// Deserializes a mime type from string
fn deserialize_mime<'de, D: Deserializer<'de>>(d: D) -> Result<Mime, D::Error> {
/// Helper struct for parsing
struct JsonStringVisitor;
impl Visitor<'_> for JsonStringVisitor {
type Value = Mime;
fn expecting(&self, formatter: &mut Formatter<'_>) -> std::fmt::Result {
formatter.write_str("a string containing a mime type")
}
fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
where
E: serde::de::Error,
{
v.parse().map_err(E::custom)
}
}
d.deserialize_any(JsonStringVisitor)
}
/// File record
#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
pub struct File {
/// ID of the file record
id: u64,
/// Path this file is mounted at
pub file_path: String,
/// MIME type of file
#[serde(serialize_with = "serialize_mime")]
#[serde(deserialize_with = "deserialize_mime")]
pub mime: Mime,
/// blake3 hash of the file to serve
pub b3hash: Hash,
}
impl Encode for File {
fn encode<E: bincode::enc::Encoder>(
&self,
encoder: &mut E,
) -> std::result::Result<(), bincode::error::EncodeError> {
self.id.encode(encoder)?;
self.file_path.encode(encoder)?;
self.mime.as_ref().encode(encoder)?;
self.b3hash.as_bytes().encode(encoder)
}
}
impl Decode for File {
fn decode<D: bincode::de::Decoder>(decoder: &mut D) -> std::result::Result<Self, DecodeError> {
let id = u64::decode(decoder)?;
let file_path = String::decode(decoder)?;
let mime = match String::decode(decoder)?.parse() {
Ok(v) => v,
Err(e) => {
return Err(DecodeError::Io {
inner: std::io::Error::other(e),
additional: 0,
});
}
};
let b3hash = <[u8; 32]>::decode(decoder)?;
Ok(Self {
id,
file_path,
mime,
b3hash: Hash::from_bytes(b3hash),
})
}
}
impl<'r> FromRow<'r, PgRow> for File {
fn from_row(row: &'r PgRow) -> std::result::Result<Self, sqlx::Error> {
let id = u64::try_from(row.try_get::<i64, _>("id")?).unwrap_or_default();
let file_path: String = row.try_get("file_path")?;
let mime: Mime = match row.try_get::<&str, _>("mime")?.parse() {
Ok(v) => v,
Err(e) => return Err(sqlx::Error::Decode(Box::new(e))),
};
let b3hash: Vec<u8> = row.try_get("b3hash")?;
if b3hash.len() != 32 {
return Err(sqlx::Error::ColumnDecode {
index: "b3hash".to_string(),
source: Box::new(std::io::Error::other("invalid b3 hash len")),
});
}
let mut b3hash_arr = [0u8; 32];
b3hash_arr.copy_from_slice(&b3hash);
Ok(Self {
id,
file_path,
mime,
b3hash: Hash::from_bytes(b3hash_arr),
})
}
}
impl File {
/// Attempts to load a file by path and mime type
///
/// # Errors
/// This function returns an error if a database error occurs while loading.
#[instrument(skip(db))]
pub async fn get_by_path_mime(db: &Database, path: &str, mime: &str) -> Result<Option<Self>> {
query_as(r#"SELECT * FROM file_map WHERE "file_path" = $1 AND "mime" = $2"#)
.bind(path)
.bind(mime)
.fetch_optional(&*db.0)
.await
.with_context(|| format!("Loading file path {path} with mime type {mime}"))
}
/// Attempts to load any files by path.
///
/// # Errors
/// This function returns an error if a database error occurs while loading.
#[instrument(skip(db))]
pub async fn get_by_path(db: &Database, path: &str) -> Result<Vec<Self>> {
query_as(r#"SELECT * FROM file_map WHERE "file_path" = $1"#)
.bind(path)
.fetch_all(&*db.0)
.await
.with_context(|| format!("Loading files with path {path}"))
}
/// Returns a paginated view into the file table
///
/// # Errors
/// This function returns an error if a database error occurs while loading.
#[instrument(skip(db))]
pub async fn list(db: &Database, after: i64, limit: usize) -> Result<Vec<Self>> {
let limit: i64 = limit.min(100).try_into().unwrap_or(100); // reasonable limit for pagination size
query_as(r#"SELECT * FROM file_map WHERE "id" > $1 LIMIT $2"#)
.bind(after)
.bind(limit)
.fetch_all(&*db.0)
.await
.with_context(|| format!("Loading up to {limit} files after id {after}"))
}
/// Creates a new file
///
/// # Errors
/// This function returns an error if a database error occurs when writing
#[instrument(skip(db))]
pub async fn new(db: &Database, path: &str, mime: &str, hash: &Hash) -> Result<()> {
query_as(
r#"INSERT INTO file_map ("file_path", "mime", "b3hash") VALUES ($1, $2, $3) ON CONFLICT ("file_path", "mime") DO UPDATE SET "b3hash" = $3 RETURNING *"#,
)
.bind(path)
.bind(mime)
.bind(hash.as_bytes().as_slice())
.fetch_one(&*db.0)
.await
.with_context(|| format!("Inserting new file {path} with mime type {mime}"))
}
/// Deletes a file record from the database. This does not perform any actual file deletion.
///
/// # Errors
/// This function returns an error if removing the entry from the database fails.
#[instrument(skip(db))]
pub async fn delete(self, db: &Database) -> Result<()> {
let id: i64 = self.id.try_into()?;
#[expect(clippy::panic, reason = "sqlx silliness")]
query!(r#"DELETE FROM file_map WHERE "id" = $1"#, id)
.execute(&*db.0)
.await
.with_context(|| {
format!(
"Deleting file {} with mime type {}",
self.file_path, self.mime
)
})?;
Ok(())
}
/// Returns the immutable ID of the object
#[must_use]
pub const fn id(&self) -> u64 {
self.id
}
/// Updates the file with new information
///
/// # Errors
/// This function returns an error if updating the entry in the database fails
#[instrument(skip(db))]
pub async fn update(&self, db: &Database) -> Result<()> {
let id: i64 = self.id.try_into()?;
let b3hash = self.b3hash.as_bytes().as_slice();
#[expect(clippy::panic, reason = "sqlx silliness")]
query!(
r#"UPDATE file_map SET "file_path" = $1, "mime" = $2, "b3hash" = $3 WHERE "id" = $4"#,
self.file_path,
self.mime.as_ref(),
b3hash,
id
)
.execute(&*db.0)
.await
.with_context(|| {
format!(
"Deleting file {} with mime type {}",
self.file_path, self.mime
)
})?;
Ok(())
}
/// Checks if a particular hash is in use
///
/// # Errors
/// This function returns an error if updating the entry in the database fails
#[instrument(skip(db))]
pub async fn is_used(db: &Database, hash: Hash) -> Result<bool> {
#[expect(clippy::panic, reason = "sqlx silliness")]
let count = query!(
r#"SELECT COUNT(*) as amount FROM file_map WHERE "b3hash" = $1"#,
hash.as_bytes()
)
.fetch_one(&*db.0)
.await
.with_context(|| format!("Checking if {hash:?} is still used."))?;
Ok(count.amount.unwrap_or_default() != 0)
}
}