backend: remove lifetimes and add different stores

Author: suaviloquence

src/cache/firestore.rs

@@ -0,0 +1,128 @@
+use crate::parse::Locations;
+use async_compression::tokio::bufread;
+use chrono::{DateTime, Utc};
+use firestore::FirestoreDb;
+use log::info;
+use tokio::io::AsyncReadExt;
+
+use super::MenuCache;
+
+const CACHES_COLLECTION: &str = "caches";
+
+#[derive(Debug)]
+pub struct Firestore {
+    db: FirestoreDb,
+    // data: String,
+}
+
+impl Firestore {
+    pub async fn open() -> crate::Result<Self> {
+        let db = FirestoreDb::new("ucsc-menu").await?;
+        Ok(Self {
+            db,
+            // data: String::new(),
+        })
+    }
+
+    pub async fn load(&mut self) -> crate::Result<Option<MenuCache>> {
+        if let Some(cache) = self
+            .db
+            .fluent()
+            .select()
+            .by_id_in(CACHES_COLLECTION)
+            .obj::<GCloudMenuCache>()
+            .one("menu")
+            .await?
+        {
+            Ok(Some(cache.decompress().await))
+        } else {
+            Ok(None)
+        }
+        // Ok(cache.decompress(&mut self.data).await)
+    }
+
+    pub async fn save(&self, cache: &MenuCache) -> crate::Result<()> {
+        let compressed = GCloudMenuCache::compress(cache).await;
+        self.db
+            .fluent()
+            .update()
+            .in_col(CACHES_COLLECTION)
+            .document_id("menu")
+            .object(&compressed)
+            // need to specify type because of dependency_on_unit_never_type_fallback
+            .execute::<()>()
+            .await?;
+        Ok(())
+    }
+}
+
+#[derive(serde::Serialize, serde::Deserialize, Default)]
+struct GCloudMenuCache {
+    cached_at: DateTime<Utc>,
+    data: Vec<u8>,
+}
+
+impl GCloudMenuCache {
+    async fn decompress<'a>(self /* dst: &mut String */) -> MenuCache {
+        if self.data.is_empty() {
+            return MenuCache {
+                cached_at: self.cached_at,
+                locations: Locations::default(),
+            };
+        }
+        let mut decompress = bufread::GzipDecoder::new(self.data.as_slice());
+        info!("Size of data compressed: {}", self.data.len());
+        let mut dst = String::new();
+        dst.reserve(self.data.len() * 8);
+        let _len = decompress
+            .read_to_string(&mut dst)
+            .await
+            .expect("should succeed");
+        info!("Size of data uncompressed: {}", dst.len());
+        let locations: Locations =
+            serde_json::from_str(&*dst).expect("Data parse should always be valid");
+        MenuCache {
+            cached_at: self.cached_at,
+            locations,
+        }
+    }
+
+    // TODO: better name
+    async fn compress(data: &MenuCache) -> Self {
+        let json = serde_json::to_string(data.locations()).unwrap();
+        let mut compressed = Vec::with_capacity(json.len() / 4);
+        let mut compress = bufread::GzipEncoder::new(std::io::Cursor::new(json));
+        compress
+            .read_buf(&mut compressed)
+            .await
+            .expect("This should succeed");
+        Self {
+            cached_at: data.cached_at,
+            data: compressed,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+
+    use std::time::Instant;
+
+    use super::*;
+
+    #[tokio::test]
+    async fn test_open() {
+        pretty_env_logger::init();
+        let mut db = Firestore::open().await.unwrap();
+        let _mc = db.load().await.unwrap();
+    }
+
+    #[tokio::test]
+    async fn test_refresh() {
+        let mut db = Firestore::open().await.unwrap();
+        let mut mc = db.load().await.unwrap();
+        let start = Instant::now();
+        todo!();
+        println!("{:?}", start.elapsed());
+    }
+}

src/cache/local.rs

@@ -0,0 +1,42 @@
+use std::path::{Path, PathBuf};
+use tokio::fs;
+
+use super::MenuCache;
+
+#[derive(Debug)]
+pub struct FileStore(PathBuf);
+
+impl FileStore {
+    pub async fn open(p: impl AsRef<Path>) -> crate::Result<Self> {
+        let p = p.as_ref();
+        // fs::File::options()
+        // .create(true)
+        // .write(true)
+        // .read(true)
+        // .open(p)
+        // .await?;
+
+        Ok(Self(p.to_owned()))
+    }
+
+    pub async fn load(&self) -> crate::Result<Option<MenuCache>> {
+        if fs::try_exists(&self.0).await? {
+            let f = fs::File::open(&self.0).await?;
+            let mut f = f.into_std().await;
+            serde_json::from_reader(&mut f).map_err(From::from)
+        } else {
+            Ok(None)
+        }
+    }
+
+    pub async fn save(&self, value: &MenuCache) -> crate::Result<()> {
+        let f = fs::File::options()
+            .create(true)
+            .write(true)
+            .open(&self.0)
+            .await?;
+        // TODO
+        let mut f = f.into_std().await;
+        serde_json::to_writer_pretty(&mut f, value).map_err(From::from)
+    }
+}