examples: Add a caps/ecaps2 generator.

examples/generate-caps.rs

@@ -0,0 +1,62 @@
+// Copyright (c) 2019 Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+use std::io::{self, Read};
+use std::env;
+use xmpp_parsers::{
+    TryFrom,
+    Element,
+    disco::DiscoInfoResult,
+    caps::{Caps, compute_disco as compute_disco_caps, hash_caps},
+    ecaps2::{ECaps2, compute_disco as compute_disco_ecaps2, hash_ecaps2},
+    hashes::Algo,
+};
+
+fn get_caps(disco: &DiscoInfoResult, node: String) -> Result<Caps, String> {
+    let caps_data = compute_disco_caps(&disco);
+    let caps_hash = hash_caps(&caps_data, Algo::Sha_1)?;
+    Ok(Caps::new(node, caps_hash))
+}
+
+fn get_ecaps2(disco: &DiscoInfoResult) -> Result<ECaps2, String> {
+    let ecaps2_data = compute_disco_ecaps2(&disco).unwrap();
+    let ecaps2_sha256 = hash_ecaps2(&ecaps2_data, Algo::Sha_256)?;
+    let ecaps2_sha3_256 = hash_ecaps2(&ecaps2_data, Algo::Sha3_256)?;
+    Ok(ECaps2::new(vec![ecaps2_sha256, ecaps2_sha3_256]))
+}
+
+fn main() -> Result<(), ()> {
+    let args: Vec<_> = env::args().collect();
+    if args.len() != 2 {
+        println!("Usage: {} <node>", args[0]);
+        return Err(());
+    }
+    let node = args[1].clone();
+
+    eprintln!("Reading a disco#info payload from stdin...");
+
+    // Read from stdin.
+    let stdin = io::stdin();
+    let mut data = String::new();
+    let mut handle = stdin.lock();
+    handle.read_to_string(&mut data).unwrap();
+
+    // Parse the payload into a DiscoInfoResult.
+    let elem: Element = data.parse().unwrap();
+    let disco = DiscoInfoResult::try_from(elem).unwrap();
+
+    // Compute both kinds of caps.
+    let caps = get_caps(&disco, node).unwrap();
+    let ecaps2 = get_ecaps2(&disco).unwrap();
+
+    // Print them.
+    let caps_elem = Element::from(caps);
+    let ecaps2_elem = Element::from(ecaps2);
+    println!("{}", String::from(&caps_elem));
+    println!("{}", String::from(&ecaps2_elem));
+
+    Ok(())
+}