postgres_es/
view_repository.rs

1use std::marker::PhantomData;
2
3use async_trait::async_trait;
4use cqrs_es::persist::{PersistenceError, ViewContext, ViewRepository};
5use cqrs_es::{Aggregate, View};
6use sqlx::postgres::PgRow;
7use sqlx::{Pool, Postgres, Row};
8
9use crate::error::PostgresAggregateError;
10
11/// A postgres backed query repository for use in backing a `GenericQuery`.
12pub struct PostgresViewRepository<V, A> {
13    insert_sql: String,
14    update_sql: String,
15    select_sql: String,
16    pool: Pool<Postgres>,
17    _phantom: PhantomData<(V, A)>,
18}
19
20impl<V, A> PostgresViewRepository<V, A>
21where
22    V: View<A>,
23    A: Aggregate,
24{
25    /// Creates a new `PostgresViewRepository` that will store serialized views in a Postgres table named
26    /// identically to the `view_name` value provided. This table should be created by the user
27    /// before using this query repository (see `/db/init.sql` sql initialization file).
28    ///
29    /// ```
30    /// # use cqrs_es::doc::MyAggregate;
31    /// # use cqrs_es::persist::doc::MyView;
32    /// use sqlx::{Pool, Postgres};
33    /// use postgres_es::PostgresViewRepository;
34    ///
35    /// fn configure_view_repo(pool: Pool<Postgres>) -> PostgresViewRepository<MyView,MyAggregate> {
36    ///     PostgresViewRepository::new("my_view_table", pool)
37    /// }
38    /// ```
39    pub fn new(view_name: &str, pool: Pool<Postgres>) -> Self {
40        let insert_sql = format!(
41            "INSERT INTO {} (payload, version, view_id) VALUES ( $1, $2, $3 )",
42            view_name
43        );
44        let update_sql = format!(
45            "UPDATE {} SET payload= $1 , version= $2 WHERE view_id= $3",
46            view_name
47        );
48        let select_sql = format!(
49            "SELECT version,payload FROM {} WHERE view_id= $1",
50            view_name
51        );
52        Self {
53            insert_sql,
54            update_sql,
55            select_sql,
56            pool,
57            _phantom: Default::default(),
58        }
59    }
60}
61
62#[async_trait]
63impl<V, A> ViewRepository<V, A> for PostgresViewRepository<V, A>
64where
65    V: View<A>,
66    A: Aggregate,
67{
68    async fn load(&self, view_id: &str) -> Result<Option<V>, PersistenceError> {
69        let row: Option<PgRow> = sqlx::query(&self.select_sql)
70            .bind(view_id)
71            .fetch_optional(&self.pool)
72            .await
73            .map_err(PostgresAggregateError::from)?;
74        match row {
75            None => Ok(None),
76            Some(row) => {
77                let view = serde_json::from_value(row.get("payload"))?;
78                Ok(Some(view))
79            }
80        }
81    }
82
83    async fn load_with_context(
84        &self,
85        view_id: &str,
86    ) -> Result<Option<(V, ViewContext)>, PersistenceError> {
87        let row: Option<PgRow> = sqlx::query(&self.select_sql)
88            .bind(view_id)
89            .fetch_optional(&self.pool)
90            .await
91            .map_err(PostgresAggregateError::from)?;
92        match row {
93            None => Ok(None),
94            Some(row) => {
95                let version = row.get("version");
96                let view = serde_json::from_value(row.get("payload"))?;
97                let view_context = ViewContext::new(view_id.to_string(), version);
98                Ok(Some((view, view_context)))
99            }
100        }
101    }
102
103    async fn update_view(&self, view: V, context: ViewContext) -> Result<(), PersistenceError> {
104        let sql = match context.version {
105            0 => &self.insert_sql,
106            _ => &self.update_sql,
107        };
108        let version = context.version + 1;
109        let payload = serde_json::to_value(&view).map_err(PostgresAggregateError::from)?;
110        sqlx::query(sql.as_str())
111            .bind(payload)
112            .bind(version)
113            .bind(context.view_instance_id)
114            .execute(&self.pool)
115            .await
116            .map_err(PostgresAggregateError::from)?;
117        Ok(())
118    }
119}
120
121#[cfg(test)]
122mod test {
123    use crate::testing::tests::{
124        Created, TestAggregate, TestEvent, TestView, TEST_CONNECTION_STRING,
125    };
126    use crate::{default_postgress_pool, PostgresViewRepository};
127    use cqrs_es::persist::{ViewContext, ViewRepository};
128
129    #[tokio::test]
130    async fn test_valid_view_repository() {
131        let pool = default_postgress_pool(TEST_CONNECTION_STRING).await;
132        let repo =
133            PostgresViewRepository::<TestView, TestAggregate>::new("test_view", pool.clone());
134        let test_view_id = uuid::Uuid::new_v4().to_string();
135
136        let view = TestView {
137            events: vec![TestEvent::Created(Created {
138                id: "just a test event for this view".to_string(),
139            })],
140        };
141        repo.update_view(view.clone(), ViewContext::new(test_view_id.to_string(), 0))
142            .await
143            .unwrap();
144        let (found, context) = repo
145            .load_with_context(&test_view_id)
146            .await
147            .unwrap()
148            .unwrap();
149        assert_eq!(found, view);
150        let found = repo.load(&test_view_id).await.unwrap().unwrap();
151        assert_eq!(found, view);
152
153        let updated_view = TestView {
154            events: vec![TestEvent::Created(Created {
155                id: "a totally different view".to_string(),
156            })],
157        };
158        repo.update_view(updated_view.clone(), context)
159            .await
160            .unwrap();
161        let found_option = repo.load(&test_view_id).await.unwrap();
162        let found = found_option.unwrap();
163
164        assert_eq!(found, updated_view);
165    }
166}
postgres_es/view_repository.rs

postgres_es/
view_repository.rs
