Serve up web wallet application (#1367)

* first addition of static wallet file server

* rustfmt

* add custom build functions to download and untar particular release of the web-wallet

* rustfmt

* remove comments

src/build/build.rs

@@ -15,10 +15,22 @@
 //! Build hooks to spit out version+build time info
 
 extern crate built;
+extern crate flate2;
+extern crate reqwest;
+extern crate tar;
 
+use flate2::read::GzDecoder;
 use std::env;
+use std::fs::{self, File};
+use std::io::prelude::*;
+use std::io::Read;
+use std::path::{self, Path, PathBuf};
+use tar::Archive;
+
+const WEB_WALLET_TAG: &str = "0.3.0.1";
 
 fn main() {
+	// build and versioning information
 	let mut opts = built::Options::default();
 	opts.set_dependencies(true);
 	built::write_built_file_with_opts(
@@ -26,4 +38,88 @@ fn main() {
 		env!("CARGO_MANIFEST_DIR"),
 		format!("{}{}", env::var("OUT_DIR").unwrap(), "/built.rs"),
 	).expect("Failed to acquire build-time information");
+
+	install_web_wallet();
+}
+
+fn download_and_decompress(target_file: &str) {
+	let req_path = format!("https://github.com/mimblewimble/grin-web-wallet/releases/download/{}/grin-web-wallet.tar.gz", WEB_WALLET_TAG);
+	let resp = reqwest::get(&req_path);
+
+	// don't interfere if this doesn't work
+	if resp.is_err() {
+		println!("Warning: Failed to download grin-web-wallet. Web wallet will not be available");
+		return;
+	}
+
+	let mut resp = resp.unwrap();
+	if resp.status().is_success() {
+		// read response
+		let mut out: Vec<u8> = vec![];
+		let r2 = resp.read_to_end(&mut out);
+		if r2.is_err() {
+			println!(
+				"Warning: Failed to download grin-web-wallet. Web wallet will not be available"
+			);
+			return;
+		}
+
+		// Gunzip
+		let mut d = GzDecoder::new(&out[..]);
+		let mut decomp: Vec<u8> = vec![];
+		d.read_to_end(&mut decomp).unwrap();
+
+		// write temp file
+		let mut buffer = File::create(target_file.clone()).unwrap();
+		buffer.write_all(&decomp).unwrap();
+		buffer.flush().unwrap();
+	}
+}
+
+/// Download and unzip tagged web-wallet build
+fn install_web_wallet() {
+	let target_file = format!(
+		"{}/grin-web-wallet-{}.tar",
+		env::var("OUT_DIR").unwrap(),
+		WEB_WALLET_TAG
+	);
+	let out_dir = env::var("OUT_DIR").unwrap();
+	let mut out_path = PathBuf::from(&out_dir);
+	out_path.pop();
+	out_path.pop();
+	out_path.pop();
+
+	// only re-download if needed
+	if !Path::new(&target_file).is_file() {
+		download_and_decompress(&target_file);
+	}
+
+	// remove old version
+	let mut remove_path = out_path.clone();
+	remove_path.push("grin-wallet");
+	let _ = fs::remove_dir_all(remove_path);
+
+	// Untar
+	let file = File::open(target_file).unwrap();
+	let mut a = Archive::new(file);
+
+	for file in a.entries().unwrap() {
+		let mut file = file.unwrap();
+		let h = file.header().clone();
+		let path = h.path().unwrap().clone().into_owned();
+		let is_dir = path.to_str().unwrap().ends_with(path::MAIN_SEPARATOR);
+		let path = path.strip_prefix("dist").unwrap();
+		let mut final_path = out_path.clone();
+		final_path.push(path);
+
+		let mut tmp: Vec<u8> = vec![];
+		file.read_to_end(&mut tmp).unwrap();
+		if is_dir {
+			fs::create_dir_all(final_path).unwrap();
+		} else {
+			let mut buffer = File::create(final_path).unwrap();
+			buffer.write_all(&tmp).unwrap();
+			buffer.flush().unwrap();
+		}
+	}
 }