[fp-rs] Retrieving device information from model ID by parsing local file with serde.

fastpair/rust/demo/rust/src/decoder.rs

@@ -11,7 +11,6 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
-
 use bluetooth::ServiceData;
 
 /// Unit struct providing parsing operations for Fast Pair advertisements.

fastpair/rust/demo/rust/src/fetcher.rs

@@ -0,0 +1,67 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+use std::fs;
+
+use serde::Deserialize;
+
+use crate::advertisement::ModelId;
+
+/// Holds Fast Pair device information parsed from JSON.
+#[derive(Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub(crate) struct DeviceInfo {
+    image_url: String,
+    name: String,
+}
+
+/// Holds top-level Fast Pair information parsed from JSON. See `local`
+/// directory for format.
+#[derive(Deserialize)]
+struct JsonData {
+    device: DeviceInfo,
+}
+
+/// Types that can fetch Fast Pair data from external storage (e.g. filesystem,
+/// remote server).
+pub(crate) trait FpFetcher {
+    fn get_device_info_from_model_id(model_id: &ModelId) -> Result<DeviceInfo, anyhow::Error>;
+}
+
+/// A unit struct for retrieving Fast Pair information from the local filesystem.
+pub(crate) struct FpFetcherLocal;
+
+impl FpFetcher for FpFetcherLocal {
+    /// Retrieve device information for the provided Model ID. Currently,
+    /// this information is saved locally. In the future, this should instead
+    /// be retrieved from a remote server and cached.
+    /// b/294456411
+    fn get_device_info_from_model_id(model_id: &ModelId) -> Result<DeviceInfo, anyhow::Error> {
+        let file_path = format!("./local/{model_id}.json");
+        let contents = fs::read_to_string(file_path).expect("Couldn't find or open file.");
+
+        let model_info: JsonData = serde_json::from_str(&contents)?;
+
+        Ok(model_info.device)
+    }
+}
+
+impl DeviceInfo {
+    pub(crate) fn name(&self) -> &String {
+        &self.name
+    }
+
+    pub(crate) fn image_url(&self) -> &String {
+        &self.image_url
+    }
+}

fastpair/rust/demo/rust/src/lib.rs

@@ -1,4 +1,5 @@
 mod advertisement;
 mod api;
-mod bridge_generated;
-mod decoder; /* AUTO INJECTED BY flutter_rust_bridge. This line may not be accurate, and you can change it according to your needs. */
+mod bridge_generated; /* AUTO INJECTED BY flutter_rust_bridge. This line may not be accurate, and you can change it according to your needs. */
+mod decoder;
+mod fetcher;