Cahce read and write

Cargo.lock

@@ -17,6 +17,21 @@ version = "2.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "512761e0bb2578dd7380c6baaa0f4ce03e84f95e960231d1dec8bf4d7d6e2627"
 
+[[package]]
+name = "android-tzdata"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e999941b234f3131b00bc13c22d06e8c5ff726d1b6318ac7eb276997bbb4fef0"
+
+[[package]]
+name = "android_system_properties"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "819e7219dbd41043ac279b19830f2efc897156490d7fd6ea916720117ee66311"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "anstream"
 version = "0.6.18"
@@ -138,6 +153,21 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
+[[package]]
+name = "chrono"
+version = "0.4.39"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7e36cc9d416881d2e24f9a963be5fb1cd90966419ac844274161d10488b3e825"
+dependencies = [
+ "android-tzdata",
+ "iana-time-zone",
+ "js-sys",
+ "num-traits",
+ "serde",
+ "wasm-bindgen",
+ "windows-targets",
+]
+
 [[package]]
 name = "clap"
 version = "4.5.23"
@@ -226,6 +256,7 @@ name = "ecb-rates"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "chrono",
  "clap",
  "colored",
  "quick-xml",
@@ -495,6 +526,29 @@ dependencies = [
  "tracing",
 ]
 
+[[package]]
+name = "iana-time-zone"
+version = "0.1.61"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "235e081f3925a06703c2d0117ea8b91f042756fd6e7a6e5d901e8ca1a996b220"
+dependencies = [
+ "android_system_properties",
+ "core-foundation-sys",
+ "iana-time-zone-haiku",
+ "js-sys",
+ "wasm-bindgen",
+ "windows-core",
+]
+
+[[package]]
+name = "iana-time-zone-haiku"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f31827a206f56af32e590ba56d5d2d085f558508192593743f16b2306495269f"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "icu_collections"
 version = "1.5.0"
@@ -751,6 +805,15 @@ dependencies = [
  "tempfile",
 ]
 
+[[package]]
+name = "num-traits"
+version = "0.2.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "071dfc062690e90b734c0b2273ce72ad0ffa95f0c74596bc250dcfd960262841"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "object"
 version = "0.36.7"
@@ -1443,6 +1506,15 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "windows-core"
+version = "0.52.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "33ab640c8d7e35bf8ba19b884ba838ceb4fba93a4e8c65a9059d08afcfc683d9"
+dependencies = [
+ "windows-targets",
+]
+
 [[package]]
 name = "windows-registry"
 version = "0.2.0"

Cargo.toml

@@ -5,6 +5,7 @@ edition = "2021"
 
 [dependencies]
 anyhow = "1.0.95"
+chrono = { version = "0.4.39", features = ["serde"] }
 clap = { version = "4.5.23", features = ["derive"] }
 colored = "2.2.0"
 quick-xml = { version = "0.37.2", features = ["async-tokio", "tokio"] }

src/cache.rs

@@ -0,0 +1,92 @@
+use std::fs;
+use std::io::{BufReader, BufWriter};
+use std::path::Path;
+
+use anyhow::Context;
+use chrono::serde::ts_seconds;
+use chrono::{DateTime, Local, Utc};
+use serde::{Deserialize, Serialize};
+
+use crate::models::ExchangeRateResult;
+use crate::os::Os;
+
+const FILE_NAME: &'static str = "cache.json";
+
+#[derive(Serialize, Deserialize, Debug)]
+pub struct Cache {
+    #[serde(with = "ts_seconds")]
+    date: DateTime<Utc>,
+
+    #[serde(rename = "camelCase")]
+    pub exchange_rate_results: Vec<ExchangeRateResult>,
+}
+
+impl Cache {
+    pub fn load() -> Option<Self> {
+        let config_opt = Os::get_current()?.get_config_path();
+        let mut config_path = match config_opt {
+            Ok(k) => k,
+            Err(e) => {
+                eprintln!("Failed to locate config dir: {:?}", e);
+                return None;
+            }
+        };
+        if let Err(e) = fs::create_dir_all(&config_path) {
+            eprintln!("Failed to create config dir: {:?}", e);
+            return None;
+        }
+        config_path.push(FILE_NAME);
+        if !config_path.try_exists().unwrap_or_default() {
+            return None;
+        }
+
+        match Self::read_config(&config_path) {
+            Ok(k) => Some(k),
+            Err(e) => {
+                eprintln!("Config path is invalid, or cannot be created: {:?}", e);
+                None
+            }
+        }
+    }
+
+    pub fn new(exchange_rate_results: Vec<ExchangeRateResult>) -> Self {
+        let date = Local::now().to_utc();
+        Self {
+            exchange_rate_results,
+            date,
+        }
+    }
+
+    pub fn save(&self) -> anyhow::Result<()> {
+        let mut config_path = Os::get_current()
+            .context("Failed to get config home")?
+            .get_config_path()?;
+        fs::create_dir_all(&config_path)?;
+        eprintln!("Config dir: {}", &config_path.display());
+
+        config_path.push(FILE_NAME);
+        eprintln!("File to write: {}", &config_path.display());
+
+        let file = fs::File::options()
+            .create(true)
+            .truncate(true)
+            .open(&config_path)?;
+
+        let writer = BufWriter::new(file);
+        serde_json::to_writer(writer, self)?;
+
+        Ok(())
+    }
+
+    pub fn validate(&self) -> bool {
+        let today = Local::now().naive_local().date();
+        let saved = self.date.naive_local().date();
+        saved == today
+    }
+
+    fn read_config(path: &Path) -> anyhow::Result<Self> {
+        let file = fs::File::open(path)?;
+        let reader = BufReader::new(file);
+        Ok(serde_json::from_reader(reader)?)
+    }
+}

src/cli.rs

@@ -21,6 +21,10 @@ pub struct Cli {
     #[arg(long = "compact")]
     pub compact: bool,
 
+    /// Override the cache
+    #[arg(long = "no-cache")]
+    pub no_cache: bool,
+
     /// Amount of data
     #[arg(value_enum, default_value_t = Resolution::TODAY, long="resolution", short='r')]
     pub resolution: Resolution,

src/lib.rs

@@ -3,6 +3,7 @@ pub mod models;
 pub mod os;
 pub mod parsing;
 pub mod table;
+pub mod cache;
 
 const APP_NAME: &'static str = "ECB-rates";
 

src/main.rs

@@ -1,4 +1,5 @@
 use clap::Parser as _;
+use ecb_rates::cache::Cache;
 use reqwest::{Client, IntoUrl};
 use std::{borrow::BorrowMut, collections::HashMap, error::Error, process::ExitCode};
 
@@ -30,12 +31,18 @@ fn filter_currencies(exchange_rate_results: &mut [ExchangeRateResult], currencie
 #[tokio::main(flavor = "current_thread")]
 async fn main() -> ExitCode {
     let cli = Cli::parse();
-
-    let mut parsed = match get_and_parse(cli.resolution.to_ecb_url()).await {
-        Ok(k) => k,
-        Err(e) => {
-            eprintln!("Failed to get/parse data from ECB: {}", e);
-            return ExitCode::FAILURE;
+    let use_cache = !cli.no_cache;
+    let cache = if use_cache { Cache::load() } else { None };
+    let cache_ok = cache.as_ref().map_or_else(|| false, |c| c.validate());
+    let mut parsed = if cache_ok {
+        cache.as_ref().unwrap().exchange_rate_results.clone()
+    } else {
+        match get_and_parse(cli.resolution.to_ecb_url()).await {
+            Ok(k) => k,
+            Err(e) => {
+                eprintln!("Failed to get/parse data from ECB: {}", e);
+                return ExitCode::FAILURE;
+            }
         }
     };
 
@@ -72,9 +79,9 @@ async fn main() -> ExitCode {
             .expect("Failed to parse content as JSON")
         }
         FormatOption::Plain => parsed
-            .into_iter()
+            .iter()
             .map(|x| {
-                let t: Table = x.into();
+                let t: Table = x.clone().into();
                 format!("{}", t)
             })
             .collect::<Vec<_>>()
@@ -82,5 +89,10 @@ async fn main() -> ExitCode {
     };
 
     println!("{}", &output);
+    if !cache_ok {
+        if let Err(e) = Cache::new(parsed).save() {
+            eprintln!("Failed to save to cache with: {:?}", e);
+        }
+    }
     ExitCode::SUCCESS
 }

src/models.rs

@@ -1,7 +1,7 @@
 use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
 
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Debug, Serialize, Deserialize, Clone)]
 pub struct ExchangeRateResult {
     pub time: String,
     pub rates: HashMap<String, f64>,