Init repo

.gitignore

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+/target

Cargo.toml

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+[package]
+name = "ytatomlink"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+anyhow = "1.0.95"
+clap = { version = "4.5.23", features = ["derive"] }
+reqwest = { version = "0.12.12", features = ["blocking"] }
+soup = "0.5.1"

README.md

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+# ytatomlink
+
+Get the Atom link to a YouTube channel URL.
+
+```
+Usage: ytatomlink <URL>
+
+Arguments:
+  <URL>  YouTube URL
+
+Options:
+  -h, --help     Print help
+  -V, --version  Print version
+```

src/main.rs

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+use anyhow::{
+    bail,
+    Context,
+    Result,
+};
+use clap::{
+    Parser,
+};
+use reqwest::{
+    Url,
+};
+use soup::prelude::{
+    Soup,
+    QueryBuilderExt,
+    NodeExt,
+};
+
+#[derive(Parser)]
+#[command(version, about, long_about = None, arg_required_else_help = true)]
+struct Cli {
+    /// YouTube URL
+    url: String,
+}
+
+fn main() -> Result<()> {
+    let cli = Cli::parse();
+
+    let url = Url::parse(&cli.url)
+        .context("Does not seem to be a URL")?;
+
+    let content = reqwest::blocking::get(url)
+        .context("Could not retrieve URL contents")?
+        .text()?;
+
+    let soup = Soup::new(&content);
+    let canonical_url = Url::parse(
+        &soup.tag("link").find_all()
+            .filter(|link| link.get("rel") == Some(String::from("canonical")))
+            .next()
+            .context("No canonical link provided")?
+            .get("href")
+            .context("Canonical link does not provide a URL")?
+    )
+        .context("Canonical URL is invalid")?;
+
+    if !&canonical_url.to_string().starts_with("https://www.youtube.com/channel/") {
+        bail!("Canonical URL does not refer to a YouTube channel");
+    }
+
+    let canonical_url_segments = canonical_url.path_segments()
+        .context("Failed to get URL segments")?
+        .collect::<Vec<_>>();
+    let channel_id = canonical_url_segments.last()
+        .context("Failed to retrieve last URL segment")?;
+
+    let atom_feed_url = format!("https://www.youtube.com/feeds/videos.xml?channel_id={}", &channel_id);
+
+    println!("{}", &atom_feed_url);
+
+    Ok(())
+}