Add storage.exists()

Author: jyn514

src/storage/database.rs

@@ -13,6 +13,12 @@ impl DatabaseBackend {
         Self { pool }
     }
 
+    pub(super) fn exists(&self, path: &str) -> Result<bool, Error> {
+        let query = "SELECT COUNT(*) > 0 FROM files WHERE path = $1";
+        let conn = self.pool.get()?;
+        Ok(conn.query(query, &[&path])?.get(0).get(0))
+    }
+
     pub(super) fn get(&self, path: &str, max_size: usize) -> Result<Blob, Error> {
         use std::convert::TryInto;
 

src/storage/mod.rs

@@ -102,6 +102,13 @@ impl Storage {
         })
     }
 
+    pub(crate) fn exists(&self, path: &str) -> Result<bool, Error> {
+        match &self.backend {
+            StorageBackend::Database(db) => db.exists(path),
+            StorageBackend::S3(s3) => s3.exists(path),
+        }
+    }
+
     pub(crate) fn get(&self, path: &str, max_size: usize) -> Result<Blob, Error> {
         let mut blob = match &self.backend {
             StorageBackend::Database(db) => db.get(path, max_size),
@@ -307,6 +314,21 @@ mod backend_tests {
     use super::*;
     use std::fs;
 
+    fn test_exists(storage: &Storage) -> Result<(), Error> {
+        assert!(!storage.exists("path/to/file.txt").unwrap());
+        let blob = Blob {
+            path: "path/to/file.txt".into(),
+            mime: "text/plain".into(),
+            date_updated: Utc::now(),
+            content: "Hello world!".into(),
+            compression: None,
+        };
+        storage.store_blobs(vec![blob])?;
+        assert!(storage.exists("path/to/file.txt")?);
+
+        Ok(())
+    }
+
     fn test_get_object(storage: &Storage) -> Result<(), Error> {
         let blob = Blob {
             path: "foo/bar.txt".into(),
@@ -570,6 +592,7 @@ mod backend_tests {
 
         tests {
             test_batched_uploads,
+            test_exists,
             test_get_object,
             test_get_too_big,
             test_store_blobs,

src/storage/s3.rs

@@ -54,6 +54,20 @@ impl S3Backend {
         })
     }
 
+    pub(super) fn exists(&self, path: &str) -> Result<bool, Error> {
+        self.runtime.handle().block_on(async {
+            let resp = self
+                .client
+                .list_objects_v2(ListObjectsV2Request {
+                    bucket: self.bucket.clone(),
+                    prefix: Some(path.into()),
+                    ..Default::default()
+                })
+                .await?;
+            Ok(resp.key_count.unwrap() > 0)
+        })
+    }
+
     pub(super) fn get(&self, path: &str, max_size: usize) -> Result<Blob, Error> {
         self.runtime.handle().block_on(async {
             let res = self