Add an HTTP cache (and --no-cache argument) (#14)

Closes https://github.com/astral-sh/puffin/issues/3.

Cargo.toml

@@ -10,5 +10,3 @@ documentation = "https://astral.sh"
 repository = "https://github.com/astral-sh/puffin"
 authors = ["Astral Software Inc. <hey@astral.sh>"]
 license = "MIT OR Apache-2.0"
-
-[workspace.dependencies]

crates/puffin-cli/Cargo.toml

@@ -23,3 +23,4 @@ pep440_rs = { version = "0.3.12" }
 tracing = { version = "0.1.37" }
 tracing-tree = { version = "0.2.5" }
 tracing-subscriber = { version = "0.3.17", features = ["env-filter"] }
+directories = "5.0.1"

crates/puffin-cli/src/commands/install.rs

@@ -29,7 +29,7 @@ enum Response {
     Version(Metadata21, Requirement),
 }
 
-pub(crate) async fn install(src: &Path) -> Result<ExitStatus> {
+pub(crate) async fn install(src: &Path, cache: Option<&Path>) -> Result<ExitStatus> {
     // Read the `requirements.txt` from disk.
     let requirements_txt = std::fs::read_to_string(src)?;
 
@@ -44,8 +44,13 @@ pub(crate) async fn install(src: &Path) -> Result<ExitStatus> {
     );
 
     // Instantiate a client.
-    let pypi_client = PypiClientBuilder::default().build();
-    let proxy_client = PypiClientBuilder::default().build();
+    let pypi_client = {
+        let mut pypi_client = PypiClientBuilder::default();
+        if let Some(cache) = cache {
+            pypi_client = pypi_client.cache(cache);
+        }
+        pypi_client.build()
+    };
 
     // A channel to fetch package metadata (e.g., given `flask`, fetch all versions) and version
     // metadata (e.g., given `flask==1.0.0`, fetch the metadata for that version).
@@ -60,7 +65,7 @@ pub(crate) async fn install(src: &Path) -> Result<ExitStatus> {
                     .map_ok(move |metadata| Response::Package(metadata, requirement)),
             ),
             Request::Version(requirement, file) => Either::Right(
-                proxy_client
+                pypi_client
                     .file(file)
                     .map_ok(move |metadata| Response::Version(metadata, requirement)),
             ),

crates/puffin-cli/src/main.rs

@@ -3,6 +3,7 @@ use std::process::ExitCode;
 
 use clap::{Args, Parser, Subcommand};
 use colored::Colorize;
+use directories::ProjectDirs;
 
 use crate::commands::ExitStatus;
 
@@ -27,6 +28,10 @@ enum Commands {
 struct InstallArgs {
     /// Path to the `requirements.text` file to install.
     src: PathBuf,
+
+    /// Avoid reading from or writing to the cache.
+    #[arg(long)]
+    no_cache: bool,
 }
 
 #[async_std::main]
@@ -35,8 +40,18 @@ async fn main() -> ExitCode {
 
     let _ = logging::setup_logging();
 
+    let dirs = ProjectDirs::from("", "", "puffin");
+
     let result = match &cli.command {
-        Commands::Install(install) => commands::install(&install.src).await,
+        Commands::Install(install) => {
+            commands::install(
+                &install.src,
+                dirs.as_ref()
+                    .map(directories::ProjectDirs::cache_dir)
+                    .filter(|_| !install.no_cache),
+            )
+            .await
+        }
     };
 
     match result {

crates/puffin-client/src/api.rs

@@ -16,8 +16,6 @@ impl PypiClient {
         &self,
         package_name: impl AsRef<str>,
     ) -> Result<SimpleJson, PypiClientError> {
-        let start = std::time::Instant::now();
-
         // Format the URL for PyPI.
         let mut url = self.registry.join("simple")?;
         url.path_segments_mut()
@@ -34,12 +32,8 @@ impl PypiClient {
 
         // Fetch from the registry.
         let text = self.simple_impl(&package_name, &url).await?;
-        let payload = serde_json::from_str(&text)
-            .map_err(move |e| PypiClientError::from_json_err(e, String::new()));
-
-        trace!("fetched metadata for {} in {:?}", url, start.elapsed());
-
-        payload
+        serde_json::from_str(&text)
+            .map_err(move |e| PypiClientError::from_json_err(e, String::new()))
     }
 
     async fn simple_impl(
@@ -69,8 +63,6 @@ impl PypiClient {
     }
 
     pub async fn file(&self, file: File) -> Result<Metadata21, PypiClientError> {
-        let start = std::time::Instant::now();
-
         // Send to the proxy.
         let url = self.proxy.join(
             file.url
@@ -82,11 +74,7 @@ impl PypiClient {
 
         // Fetch from the registry.
         let text = self.file_impl(&file.filename, &url).await?;
-        let payload = Metadata21::parse(text.as_bytes()).map_err(std::convert::Into::into);
-
-        trace!("fetched file {} in {:?}", url, start.elapsed());
-
-        payload
+        Metadata21::parse(text.as_bytes()).map_err(std::convert::Into::into)
     }
 
     async fn file_impl(

crates/puffin-requirements/Cargo.toml

@@ -16,7 +16,8 @@ serde = { version = "1.0.188" }
 thiserror = { version = "1.0.49" }
 
 [dev-dependencies]
-criterion = "0.5.1"
+criterion = { version = "0.5.1" }
+insta = { version = "1.33.0" }
 
 [[bench]]
 name = "parser"