Refactored the database module and its tests

1 files changed, 263 insertions, 0 deletions

diff --git a/src/database/mod.rs b/src/database/mod.rs
new file mode 100644
index 0000000..6abe72c
--- /dev/null
+++ b/src/database/mod.rs
@@ -0,0 +1,263 @@
+#![warn(missing_docs)]
+use async_trait::async_trait;
+use serde::{Serialize,Deserialize};
+
+#[cfg(test)]
+mod memory;
+#[cfg(test)]
+pub(crate) use crate::database::memory::MemoryStorage;
+
+use crate::indieauth::User;
+
+mod redis;
+pub use crate::database::redis::RedisStorage;
+
+#[derive(Serialize, Deserialize, PartialEq, Debug)]
+pub struct MicropubChannel {
+    pub uid: String,
+    pub name: String
+}
+
+#[derive(Debug, Clone, Copy)]
+pub enum ErrorKind {
+    Backend,
+    PermissionDenied,
+    JSONParsing,
+    NotFound,
+    Other
+}
+
+#[derive(Debug)]
+pub struct StorageError {
+    pub msg: String,
+    source: Option<Box<dyn std::error::Error>>,
+    pub kind: ErrorKind
+}
+unsafe impl Send for StorageError {}
+unsafe impl Sync for StorageError {}
+impl std::error::Error for StorageError {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        self.source.as_ref().map(|e| e.as_ref())
+    }
+}
+impl From<serde_json::Error> for StorageError {
+    fn from(err: serde_json::Error) -> Self {
+        Self {
+            msg: format!("{}", err),
+            source: Some(Box::new(err)),
+            kind: ErrorKind::JSONParsing
+        }
+    }
+}
+impl std::fmt::Display for StorageError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match match self.kind {
+            ErrorKind::Backend => write!(f, "backend error: "),
+            ErrorKind::JSONParsing => write!(f, "error while parsing JSON: "),
+            ErrorKind::PermissionDenied => write!(f, "permission denied: "),
+            ErrorKind::NotFound => write!(f, "not found: "),
+            ErrorKind::Other => write!(f, "generic storage layer error: ")
+        } {
+            Ok(_) => write!(f, "{}", self.msg),
+            Err(err) => Err(err)
+        }
+    }
+}
+impl serde::Serialize for StorageError {
+    fn serialize<S: serde::Serializer>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error> {
+        serializer.serialize_str(&self.to_string())
+    }
+}
+impl StorageError {
+    /// Create a new StorageError of an ErrorKind with a message.
+    fn new(kind: ErrorKind, msg: &str) -> Self {
+        return StorageError {
+            msg: msg.to_string(),
+            source: None,
+            kind
+        }
+    }
+    /// Get the kind of an error.
+    pub fn kind(&self) -> ErrorKind {
+        self.kind
+    }
+}
+
+
+/// A special Result type for the Micropub backing storage.
+pub type Result<T> = std::result::Result<T, StorageError>;
+
+/// A storage backend for the Micropub server.
+/// 
+/// Implementations should note that all methods listed on this trait MUST be fully atomic
+/// or lock the database so that write conflicts or reading half-written data should not occur.
+#[async_trait]
+pub trait Storage: Clone + Send + Sync {
+    /// Check if a post exists in the database.
+    async fn post_exists(&self, url: &str) -> Result<bool>;
+
+    /// Load a post from the database in MF2-JSON format, deserialized from JSON.
+    async fn get_post(&self, url: &str) -> Result<Option<serde_json::Value>>;
+
+    /// Save a post to the database as an MF2-JSON structure.
+    /// 
+    /// Note that the `post` object MUST have `post["properties"]["uid"][0]` defined.
+    async fn put_post<'a>(&self, post: &'a serde_json::Value) -> Result<()>;
+
+    /*/// Save a post and add it to the relevant feeds listed in `post["properties"]["channel"]`.
+    /// 
+    /// Note that the `post` object MUST have `post["properties"]["uid"][0]` defined 
+    /// and `post["properties"]["channel"]` defined, even if it's empty.
+    async fn put_and_index_post<'a>(&mut self, post: &'a serde_json::Value) -> Result<()>;*/
+    
+    /// Modify a post using an update object as defined in the Micropub spec.
+    /// 
+    /// Note to implementors: the update operation MUST be atomic OR MUST lock the database
+    /// to prevent two clients overwriting each other's changes.
+    /// 
+    /// You can assume concurrent updates will never contradict each other, since that will be dumb.
+    /// The last update always wins.
+    async fn update_post<'a>(&self, url: &'a str, update: serde_json::Value) -> Result<()>;
+
+    /// Get a list of channels available for the user represented by the `user` object to write.
+    async fn get_channels(&self, user: &User) -> Result<Vec<MicropubChannel>>;
+
+    /// Fetch a feed at `url` and return a an h-feed object containing
+    /// `limit` posts after a post by url `after`, filtering the content
+    /// in context of a user specified by `user` (or an anonymous user).
+    /// 
+    /// Specifically, private posts that don't include the user in the audience
+    /// will be elided from the feed, and the posts containing location and not
+    /// specifying post["properties"]["location-visibility"][0] == "public"
+    /// will have their location data (but not check-in data) stripped.
+    /// 
+    /// This function is used as an optimization so the client, whatever it is,
+    /// doesn't have to fetch posts, then realize some of them are private, and
+    /// fetch more posts.
+    /// 
+    /// Note for implementors: if you use streams to fetch posts in parallel
+    /// from the database, preferably make this method use a connection pool
+    /// to reduce overhead of creating a database connection per post for
+    /// parallel fetching.
+    async fn read_feed_with_limit<'a>(&self, url: &'a str, after: &'a Option<String>, limit: usize, user: &'a Option<String>) -> Result<Option<serde_json::Value>>;
+
+    /// Deletes a post from the database irreversibly. 'nuff said. Must be idempotent.
+    async fn delete_post<'a>(&self, url: &'a str) -> Result<()>;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{Storage, MicropubChannel};
+    use std::{process};
+    use std::time::Duration;
+    use serde_json::json;
+
+    async fn test_backend_basic_operations<Backend: Storage>(backend: Backend) {
+        let post: serde_json::Value = json!({
+            "type": ["h-entry"],
+            "properties": {
+                "content": ["Test content"],
+                "author": ["https://fireburn.ru/"],
+                "uid": ["https://fireburn.ru/posts/hello"],
+                "url": ["https://fireburn.ru/posts/hello", "https://fireburn.ru/posts/test"]
+            }
+        });
+        let key = post["properties"]["uid"][0].as_str().unwrap().to_string();
+        let alt_url = post["properties"]["url"][1].as_str().unwrap().to_string();
+
+        // Reading and writing
+        backend.put_post(&post).await.unwrap();
+        if let Ok(Some(returned_post)) = backend.get_post(&key).await {
+            assert!(returned_post.is_object());
+            assert_eq!(returned_post["type"].as_array().unwrap().len(), post["type"].as_array().unwrap().len());
+            assert_eq!(returned_post["type"].as_array().unwrap(), post["type"].as_array().unwrap());
+            let props: &serde_json::Map<String, serde_json::Value> = post["properties"].as_object().unwrap();
+            for key in props.keys() {
+                assert_eq!(returned_post["properties"][key].as_array().unwrap(), post["properties"][key].as_array().unwrap())
+            }
+        } else { panic!("For some reason the backend did not return the post.") }
+        // Check the alternative URL - it should return the same post
+        if let Ok(Some(returned_post)) = backend.get_post(&alt_url).await {
+            assert!(returned_post.is_object());
+            assert_eq!(returned_post["type"].as_array().unwrap().len(), post["type"].as_array().unwrap().len());
+            assert_eq!(returned_post["type"].as_array().unwrap(), post["type"].as_array().unwrap());
+            let props: &serde_json::Map<String, serde_json::Value> = post["properties"].as_object().unwrap();
+            for key in props.keys() {
+                assert_eq!(returned_post["properties"][key].as_array().unwrap(), post["properties"][key].as_array().unwrap())
+            }
+        } else { panic!("For some reason the backend did not return the post.") }
+    }
+
+    async fn test_backend_get_channel_list<Backend: Storage>(backend: Backend) {
+        let feed = json!({
+            "type": ["h-feed"],
+            "properties": {
+                "name": ["Main Page"],
+                "author": ["https://fireburn.ru/"],
+                "uid": ["https://fireburn.ru/feeds/main"]
+            },
+            "children": []
+        });
+        backend.put_post(&feed).await.unwrap();
+        let chans = backend.get_channels(&crate::indieauth::User::new("https://fireburn.ru/", "https://quill.p3k.io/", "create update media")).await.unwrap();
+        assert_eq!(chans.len(), 1);
+        assert_eq!(chans[0], MicropubChannel { uid: "https://fireburn.ru/feeds/main".to_string(), name: "Main Page".to_string() });
+    }
+
+    #[async_std::test]
+    async fn test_memory_storage_basic_operations() {
+        let backend = super::MemoryStorage::new();
+        test_backend_basic_operations(backend).await
+    }
+    #[async_std::test]
+    async fn test_memory_storage_channel_support() {
+        let backend = super::MemoryStorage::new();
+        test_backend_get_channel_list(backend).await
+    }
+
+    async fn get_redis_backend() -> (tempdir::TempDir, process::Child, super::RedisStorage) {
+        let tempdir = tempdir::TempDir::new("redis").expect("failed to create tempdir");
+        let socket = tempdir.path().join("redis.sock");
+        let redis_child = process::Command::new("redis-server")
+            .current_dir(&tempdir)
+            .arg("--port").arg("0")
+            .arg("--unixsocket").arg(&socket)
+            .stdout(process::Stdio::null())
+            .stderr(process::Stdio::null())
+            .spawn().expect("Failed to spawn Redis");
+        println!("redis+unix:///{}", socket.to_str().unwrap());
+        let uri = format!("redis+unix:///{}", socket.to_str().unwrap());
+        // There should be a slight delay, we need to wait for Redis to spin up
+        let client = redis::Client::open(uri.clone()).unwrap();
+        let millisecond = Duration::from_millis(1);
+        let mut retries: usize = 0;
+        const MAX_RETRIES: usize = 10 * 1000/*ms*/;
+        while let Err(err) = client.get_connection() {
+            if err.is_connection_refusal() {
+                async_std::task::sleep(millisecond).await;
+                retries += 1;
+                if retries > MAX_RETRIES {
+                    panic!("Timeout waiting for Redis, last error: {}", err);
+                }
+            } else {
+                panic!("Could not connect: {}", err);
+            }
+        }
+        let backend = super::RedisStorage::new(uri).await.unwrap();
+
+        return (tempdir, redis_child, backend)
+    }
+
+    #[async_std::test]
+    async fn test_redis_storage_basic_operations() {
+        let (_, mut redis, backend) = get_redis_backend().await;
+        test_backend_basic_operations(backend).await;
+        redis.kill().expect("Redis wasn't running");
+    }
+    #[async_std::test]
+    async fn test_redis_storage_channel_support() {
+        let (_, mut redis, backend) = get_redis_backend().await;
+        test_backend_get_channel_list(backend).await;
+        redis.kill().expect("Redis wasn't running");
+    }
+}