Add writing to XML

.gitignore

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+/target

Cargo.toml

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+[package]
+name = "bib-watcher"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+chrono = "0.4.23"
+reqwest = { version = "0.11.13", features = ["blocking"]}
+rss = "2.0.2"
+scraper = "0.14.0"

bib.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<rss version="2.0">
+    <channel>
+        <title>Bib Watcher</title>
+        <link>https://phlaym.net</link>
+        <description>Watches availability status of library books</description>
+        <item>
+            <title>Klufti Affenhitze</title>
+            <link>https://webopac.winbiap.de/konstanz/detail.aspx?data=U29ydD1adWdhbmdzZGF0dW0gKEJpYmxpb3RoZWspJmFtcDtjbWQ9MSZhbXA7cFM9MTAmYW1wO0NhdGFsb2d1ZUlkPTEwNjYwNCZhbXA7cEk9MCZhbXA7c0M9Y18wPTAlJW1fMD0xJSVmXzA9MiUlb18wPTglJXZfMD1hZmZlbmhpdHplJSVnXzA9LTEmYW1wO3NDYXRJZD0xMDY2MDQmYW1wO3BhZ2VJZD0yJmFtcDtTcmM9Mg%3d%3d</link>
+            <description><![CDATA[entliehen]]></description>
+            <pubDate>Tue, 17 Jan 2023 19:45:23 +0000</pubDate>
+        </item>
+    </channel>
+</rss>

src/main.rs

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+use reqwest::header;
+use rss::{Channel, ChannelBuilder, ItemBuilder};
+use scraper::{Html, Selector};
+use std::{error::Error, fs::File, io::BufReader};
+
+use chrono::prelude::*;
+
+const FILE_NAME: &str = "bib.xml";
+
+fn get_last_status(title: &str) -> Result<String, Box<dyn Error>> {
+    let file = File::open(FILE_NAME);
+    let channel = match file {
+        Ok(f) => Channel::read_from(BufReader::new(f)),
+        Err(_) => {
+            let c = ChannelBuilder::default()
+                .title("Bib Watcher".to_string())
+                .description("Watches availability status of library books".to_string())
+                .link("https://phlaym.net".to_string())
+                .build();
+            c.pretty_write_to(File::create(FILE_NAME)?, b' ', 4)?;
+            Ok(c)
+        }
+    }?;
+    Ok(channel
+        .items()
+        .iter()
+        .filter(|i| i.title().unwrap_or("") == title)
+        .last()
+        .and_then(|i| i.description())
+        .unwrap_or("")
+        .into())
+}
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let searches = [(
+        "Klufti Affenhitze",
+        "https://webopac.winbiap.de/konstanz/detail.aspx?data=U29ydD1adWdhbmdzZGF0dW0gKEJpYmxpb3RoZWspJmFtcDtjbWQ9MSZhbXA7cFM9MTAmYW1wO0NhdGFsb2d1ZUlkPTEwNjYwNCZhbXA7cEk9MCZhbXA7c0M9Y18wPTAlJW1fMD0xJSVmXzA9MiUlb18wPTglJXZfMD1hZmZlbmhpdHplJSVnXzA9LTEmYW1wO3NDYXRJZD0xMDY2MDQmYW1wO3BhZ2VJZD0yJmFtcDtTcmM9Mg%3d%3d"
+    )]
+    .iter()
+    .cloned()
+    .collect::<std::collections::HashMap<&str, &str>>();
+    for (title, url) in searches {
+        search(url, title)?
+    }
+    /*
+    let url = "https://webopac.winbiap.de/konstanz/detail.aspx?data=U29ydD1adWdhbmdzZGF0dW0gKEJpYmxpb3RoZWspJmFtcDtjbWQ9MSZhbXA7cFM9MTAmYW1wO0NhdGFsb2d1ZUlkPTEwNjYwNCZhbXA7cEk9MCZhbXA7c0M9Y18wPTAlJW1fMD0xJSVmXzA9MiUlb18wPTglJXZfMD1hZmZlbmhpdHplJSVnXzA9LTEmYW1wO3NDYXRJZD0xMDY2MDQmYW1wO3BhZ2VJZD0yJmFtcDtTcmM9Mg%3d%3d";
+
+    if status != "entliehen" {
+        Notification::new()
+            .summary("Klufti News")
+            .body(&format!("Neuer Status: {}", status))
+            .show()?;
+    }*/
+    Ok(())
+}
+
+fn search(url: &str, title: &str) -> Result<(), Box<dyn Error>> {
+    let mut headers = header::HeaderMap::new();
+    headers.append(
+        header::ACCEPT,
+        header::HeaderValue::from_static(
+            "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
+        ),
+    );
+    headers.append(
+        header::HOST,
+        header::HeaderValue::from_static("webopac.winbiap.de"),
+    );
+    headers.append(
+        header::REFERER,
+        header::HeaderValue::from_static("https://webopac.winbiap.de/"),
+    );
+    let client = reqwest::blocking::Client::builder()
+        .default_headers(headers)
+        .build()?;
+    let request = client.get(url).build()?;
+    let response = client.execute(request)?;
+    let status = parse(&response.text()?)?;
+    let last_status = get_last_status(title)?;
+    if status != last_status {
+        let file = File::open(FILE_NAME);
+        let mut channel = match file {
+            Ok(f) => Channel::read_from(BufReader::new(f)),
+            Err(_) => Ok(ChannelBuilder::default()
+                .title("Bib Watcher".to_string())
+                .description("Watches availability status of library books".to_string())
+                .link("https://phlaym.net".to_string())
+                .build()),
+        }?;
+        let mut items = channel.clone().into_items();
+        items.push(
+            ItemBuilder::default()
+                .title(Some(title.to_string()))
+                .pub_date(Some(Utc::now().to_rfc2822()))
+                .link(Some(url.to_string()))
+                .description(Some(status))
+                .build(),
+        );
+        channel.set_items(items);
+        channel.pretty_write_to(File::create(FILE_NAME)?, b' ', 4)?;
+    }
+    Ok(())
+}
+
+fn parse(html: &str) -> Result<String, Box<dyn Error>> {
+    let document = Html::parse_document(html);
+    let selector = Selector::parse("#detail-left-wrapper .mediaStatus span")?;
+    Ok(document
+        .select(&selector)
+        .next()
+        .map(|r| r.text().collect::<String>())
+        .unwrap_or_else(|| "Unknown".into()))
+}