Record demo for readme

Uses a crate in `bin/demo` to output a demo script of commands, with a
per-character and per-line delay, and a dummy prompt. Capture output
and render to a gif.

type: documentation

Cargo.lock

@@ -187,6 +187,10 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "demo"
+version = "0.0.0"
+
 [[package]]
 name = "difference"
 version = "2.0.0"

Cargo.toml

@@ -62,6 +62,8 @@ temptree = "0.0.0"
 
 [workspace]
 members = [
+  # run commands for demo animation
+  "bin/demo",
   # generate table of contents and table of supported BEPs in README.md
   "bin/update-readme",
 ]

README.md

@@ -10,6 +10,8 @@ At the moment, creation, viewing, and verification of `.torrent` files is suppor
 
 For more about the project and its goals, check out [this post](https://rodarmor.com/blog/intermodal).
 
+![demonstration animation](https://raw.githubusercontent.com/casey/intermodal/master/www/demo.gif)
+
 ## Manual
 
 - [General](#general)

bin/demo/Cargo.toml

@@ -0,0 +1,5 @@
+[package]
+name = "demo"
+version = "0.0.0"
+authors = ["Casey Rodarmor <casey@rodarmor.com>"]
+edition = "2018"

bin/demo/src/main.rs

@@ -0,0 +1,78 @@
+use std::{
+  error::Error,
+  io::{stdout, Write},
+  path::{Path, PathBuf},
+  process::Command,
+  thread::sleep,
+  time::Duration,
+};
+
+type Result<T, E = Box<dyn Error>> = std::result::Result<T, E>;
+
+const SCRIPT: &str = "
+  ls -l 9front
+  imdl torrent create --input 9front
+  imdl torrent show --input 9front.torrent
+  imdl torrent verify --input 9front.torrent
+  imdl torrent link --input 9front.torrent
+";
+
+const PROMPT: &str = "\x1b[0;34m$\x1b[0m ";
+
+const CPM: u64 = 600;
+
+fn commands() -> Vec<Vec<&'static str>> {
+  SCRIPT
+    .lines()
+    .map(|line| line.trim())
+    .filter(|line| !line.is_empty())
+    .map(|line| line.split(' ').collect())
+    .collect()
+}
+
+fn print(text: &str) -> Result<()> {
+  stdout().write_all(text.as_bytes())?;
+  stdout().flush()?;
+  Ok(())
+}
+
+fn replace(bin: &str) -> Result<PathBuf> {
+  match bin {
+    "ls" => Ok("exa".into()),
+    "imdl" => Ok(Path::new("./target/release/imdl").canonicalize()?),
+    _ => Ok(bin.into()),
+  }
+}
+
+fn run(command: &[&str]) -> Result<()> {
+  Command::new(replace(command[0])?)
+    .args(&command[1..])
+    .current_dir("tmp")
+    .status()?;
+  Ok(())
+}
+
+fn main() -> Result<()> {
+  let char_delay = Duration::from_millis(1000 * 60 / CPM);
+  let line_delay = char_delay * 7;
+
+  for (i, command) in commands().iter().enumerate() {
+    print(PROMPT)?;
+
+    if i > 0 {
+      sleep(line_delay);
+    }
+
+    let mut line = command.join(" ");
+    line.push('\n');
+
+    for c in line.chars() {
+      sleep(char_delay);
+      print(&c.to_string())?;
+    }
+
+    run(&command)?;
+  }
+
+  Ok(())
+}

justfile

@@ -58,6 +58,9 @@ dev-deps:
 	brew install grip
 	cargo install mdbook
 	cargo install cargo-watch
+	npm install --global asciicast2gif
+	brew install imagemagick
+	brew install gifsicle
 
 # update readme table of contents
 update-toc:
@@ -101,6 +104,19 @@ publish: publish-check
 	git push github {{version}}
 	cargo publish
 
+# record demo animation
+record:
+	#!/usr/bin/env bash
+	set -euxo pipefail
+	cargo build --release --all
+	rm -f tmp/9front.torrent
+	asciinema rec \
+		--command ./target/release/demo \
+		--overwrite \
+		tmp/demo.json
+	asciinema upload tmp/demo.json
+	asciicast2gif tmp/demo.json www/demo.gif
+
 # open site index
 www:
 	open www/index.html