rattler_networking 0.22.2

//! file storage for passwords.
use async_fd_lock::{
    blocking::{LockRead, LockWrite},
    RwLockWriteGuard,
};
use std::collections::BTreeMap;
use std::fs::File;
use std::io::BufWriter;
use std::path::Path;
use std::path::PathBuf;
use std::sync::{Arc, RwLock};

use crate::authentication_storage::{AuthenticationStorageError, StorageBackend};
use crate::Authentication;

#[derive(Clone, Debug)]
struct FileStorageCache {
    content: BTreeMap<String, Authentication>,
    file_exists: bool,
}

/// A struct that implements storage and access of authentication
/// information backed by a on-disk JSON file
#[derive(Clone, Debug)]
pub struct FileStorage {
    /// The path to the JSON file
    pub path: PathBuf,

    /// The cache of the file storage
    /// This is used to avoid reading the file from disk every time
    /// a credential is accessed
    cache: Arc<RwLock<FileStorageCache>>,
}

/// An error that can occur when accessing the file storage
#[derive(thiserror::Error, Debug)]
pub enum FileStorageError {
    /// An IO error occurred when accessing the file storage
    #[error("IO error: {0}")]
    IOError(#[from] std::io::Error),

    /// Failed to lock the file storage file
    #[error("failed to lock file storage file: {0:?}")]
    FailedToLock(async_fd_lock::LockError<std::fs::File>),

    /// An error occurred when (de)serializing the credentials
    #[error("JSON error: {0}")]
    JSONError(#[from] serde_json::Error),
}

impl FileStorageCache {
    pub fn from_path(path: &Path) -> Result<Self, FileStorageError> {
        let file_exists = path.exists();
        let content = if file_exists {
            let read_guard = File::options()
                .read(true)
                .open(path)?
                .lock_read()
                .map_err(FileStorageError::FailedToLock)?;
            serde_json::from_reader(read_guard)?
        } else {
            BTreeMap::new()
        };

        Ok(Self {
            content,
            file_exists,
        })
    }
}

impl FileStorage {
    /// Create a new file storage with the given path
    pub fn from_path(path: PathBuf) -> Result<Self, FileStorageError> {
        // read the JSON file if it exists, and store it in the cache
        let cache = Arc::new(RwLock::new(FileStorageCache::from_path(&path)?));

        Ok(Self { path, cache })
    }

    /// Create a new file storage with the default path
    pub fn new() -> Result<Self, FileStorageError> {
        let path = dirs::home_dir()
            .unwrap()
            .join(".rattler")
            .join("credentials.json");
        Self::from_path(path)
    }

    /// Updates the cache by reading the JSON file and deserializing it into a `BTreeMap`, or return an empty `BTreeMap` if the
    /// file does not exist
    fn read_json(&self) -> Result<BTreeMap<String, Authentication>, FileStorageError> {
        let new_cache = FileStorageCache::from_path(&self.path)?;
        let mut cache = self.cache.write().unwrap();
        cache.content = new_cache.content;
        cache.file_exists = new_cache.file_exists;
        Ok(cache.content.clone())
    }

    /// Serialize the given `BTreeMap` and write it to the JSON file
    fn write_json(&self, dict: &BTreeMap<String, Authentication>) -> Result<(), FileStorageError> {
        let parent = self
            .path
            .parent()
            .ok_or(FileStorageError::IOError(std::io::Error::new(
                std::io::ErrorKind::NotFound,
                "Parent directory not found",
            )))?;
        std::fs::create_dir_all(parent)?;
        let write_guard: std::result::Result<
            RwLockWriteGuard<File>,
            async_fd_lock::LockError<File>,
        > = File::options()
            .create(true)
            .write(true)
            .truncate(true)
            .open(&self.path)?
            .lock_write();
        let write_guard = write_guard.map_err(FileStorageError::FailedToLock)?;
        serde_json::to_writer(BufWriter::new(write_guard), dict)?;

        // Store the new data in the cache
        let mut cache = self.cache.write().unwrap();
        cache.content = dict.clone();
        cache.file_exists = true;

        Ok(())
    }
}

impl StorageBackend for FileStorage {
    fn store(
        &self,
        host: &str,
        authentication: &crate::Authentication,
    ) -> Result<(), AuthenticationStorageError> {
        let mut dict = self.read_json()?;
        dict.insert(host.to_string(), authentication.clone());
        Ok(self.write_json(&dict)?)
    }

    fn get(&self, host: &str) -> Result<Option<crate::Authentication>, AuthenticationStorageError> {
        let cache = self.cache.read().unwrap();
        Ok(cache.content.get(host).cloned())
    }

    fn delete(&self, host: &str) -> Result<(), AuthenticationStorageError> {
        let mut dict = self.read_json()?;
        if dict.remove(host).is_some() {
            Ok(self.write_json(&dict)?)
        } else {
            Ok(())
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use insta::assert_snapshot;
    use std::{fs, io::Write};
    use tempfile::tempdir;

    #[test]
    fn test_file_storage() {
        let file = tempdir().unwrap();
        let path = file.path().join("test.json");

        let storage = FileStorage::from_path(path.clone()).unwrap();

        assert_eq!(storage.get("test").unwrap(), None);

        storage
            .store("test", &Authentication::CondaToken("password".to_string()))
            .unwrap();
        assert_eq!(
            storage.get("test").unwrap(),
            Some(Authentication::CondaToken("password".to_string()))
        );

        storage
            .store(
                "bearer",
                &Authentication::BearerToken("password".to_string()),
            )
            .unwrap();
        storage
            .store(
                "basic",
                &Authentication::BasicHTTP {
                    username: "user".to_string(),
                    password: "password".to_string(),
                },
            )
            .unwrap();

        assert_snapshot!(fs::read_to_string(&path).unwrap());

        storage.delete("test").unwrap();
        assert_eq!(storage.get("test").unwrap(), None);

        let mut file = std::fs::File::create(&path).unwrap();
        file.write_all(b"invalid json").unwrap();

        assert!(FileStorage::from_path(path.clone()).is_err());
    }
}