[web] Implement dumping of the static assets

web/src/configuration.rs

@@ -33,11 +33,11 @@ pub enum SubCommand {
 /// If serving static files, all files should be available under the /static/filename.ext
 /// route.
 pub struct DumpStatics {
-	#[argh(option, default = "String::from(\"./static/\")")]
+	#[argh(positional, default = "PathBuf::from(\"./static/\")")]
 	/// the directory to write the static files to
 	///
 	/// Defaults to ./static/
-	pub destination: String,
+	pub destination: PathBuf,
 }
 
 #[derive(FromArgs, PartialEq, Debug)]

web/src/main.rs

@@ -5,6 +5,7 @@ pub mod configuration;
 
 use configuration::ConfigError;
 
+use std::io::ErrorKind;
 use std::net::SocketAddr;
 use std::process::exit;
 use std::collections::HashMap;
@@ -150,8 +151,38 @@ async fn main() -> std::io::Result<()> {
 	let args: configuration::PronounsTodayArgs = argh::from_env();
 
 	match args.command {
-		configuration::SubCommand::DumpStatics(_subargs) => {
-			println!("Support for dumping statics not yet implemented");
+		configuration::SubCommand::DumpStatics(subargs) => {
+			match statics::dump_statics(
+				subargs.destination.as_ref(),
+				statics::STATIC_ASSETS
+			) {
+				Ok(()) => {
+					println!("Successfully dumped all static assets to {}.  Serve this \
+							 directory under /static/ in order to speed up delivery of \
+							 static assets", subargs.destination.display());
+				}
+				Err((e, path)) => {
+					match e.kind() {
+						ErrorKind::PermissionDenied => {
+							eprintln!(
+								"Permission denied for {}",
+								path.display(),
+							);
+						},
+						ErrorKind::AlreadyExists => {
+							eprintln!(
+								"Refusing to overwrite existing file {}",
+								path.display(),
+							);
+						},
+						_ => {
+							eprintln!("An unexpected IO error occurred while trying to \
+										interact with {}", path.display());
+							return Err(e);
+						}
+					};
+				}
+			};
 			Ok(())
 		}
 		configuration::SubCommand::Run(subargs) => {

web/src/statics.rs

@@ -1,3 +1,10 @@
+use std::path::PathBuf;
+use std::fs::OpenOptions;
+use std::fs::File;
+use std::fs::create_dir_all;
+use std::io;
+use std::io::Write;
+use std::path::Path;
 use actix_web::http::StatusCode;
 use actix_web::HttpResponse;
 use actix_web::HttpRequest;
@@ -49,6 +56,34 @@ impl StaticAsset {
 	}
 }
 
+/// Attempt to dump several static assets to a directory
+///
+/// Creates the destination directory and all of the necessary parent directories, if
+/// necessary.  Will refuse to overwrite existing files.
+pub fn dump_statics(destination: &Path, assets: &[StaticAsset]) -> Result<(), (io::Error, PathBuf)> {
+	create_dir_all(destination)
+		.map_err(|e| (e, destination.into()))?;
+
+	let files = assets.iter()
+		.map(|asset| {
+			let path = destination.join(asset.filename);
+			OpenOptions::new()
+				.write(true)
+				.create_new(true)
+				.open(&path)
+				.map_err(|e| (e, path.clone()))
+				.map(|file| (file, asset.bytes, path))
+		})
+		.collect::<Result<Vec<(File, &'static [u8], PathBuf)>, (io::Error, PathBuf)>>()?;
+
+	files.into_iter()
+		.map(|(mut file, bytes, path)|
+			 file.write_all(bytes)
+				.map_err(|e| (e, path))
+		)
+		.collect::<Result<(), (io::Error, PathBuf)>>()
+}
+
 
 /// Generate a [`StaticAsset`] at compiletime from a filename.
 #[cfg(any(feature = "embed_static_assets", feature = "ogp_images"))]