feat(schedule)!: move schedule parser, downloader, and updater to external library

This can be used to support more schedule formats in the future.

providers/provider-engels-polytechnic/src/xls_downloader.rs

@@ -0,0 +1,237 @@
+use chrono::{DateTime, Utc};
+use derive_more::{Display, Error};
+use std::mem::discriminant;
+use std::sync::Arc;
+use utoipa::ToSchema;
+
+/// XLS data retrieval errors.
+#[derive(Clone, Debug, ToSchema, Display, Error)]
+pub enum FetchError {
+    /// File url is not set.
+    #[display("The link to the timetable was not provided earlier.")]
+    NoUrlProvided,
+
+    /// Unknown error.
+    #[display("An unknown error occurred while downloading the file.")]
+    #[schema(value_type = String)]
+    Unknown(Arc<reqwest::Error>),
+
+    /// Server returned a status code different from 200.
+    #[display("Server returned a status code {status_code}.")]
+    BadStatusCode { status_code: u16 },
+
+    /// The url leads to a file of a different type.
+    #[display("The link leads to a file of type '{content_type}'.")]
+    BadContentType { content_type: String },
+
+    /// Server doesn't return expected headers.
+    #[display("Server doesn't return expected header(s) '{expected_header}'.")]
+    BadHeaders { expected_header: String },
+}
+
+impl FetchError {
+    pub fn unknown(error: Arc<reqwest::Error>) -> Self {
+        Self::Unknown(error)
+    }
+
+    pub fn bad_status_code(status_code: u16) -> Self {
+        Self::BadStatusCode { status_code }
+    }
+
+    pub fn bad_content_type(content_type: &str) -> Self {
+        Self::BadContentType {
+            content_type: content_type.to_string(),
+        }
+    }
+
+    pub fn bad_headers(expected_header: &str) -> Self {
+        Self::BadHeaders {
+            expected_header: expected_header.to_string(),
+        }
+    }
+}
+
+impl PartialEq for FetchError {
+    fn eq(&self, other: &Self) -> bool {
+        discriminant(self) == discriminant(other)
+    }
+}
+
+/// Result of XLS data retrieval.
+#[derive(Debug, PartialEq)]
+pub struct FetchOk {
+    /// File upload date.
+    pub uploaded_at: DateTime<Utc>,
+
+    /// Date data received.
+    pub requested_at: DateTime<Utc>,
+
+    /// File data.
+    pub data: Option<Vec<u8>>,
+}
+
+impl FetchOk {
+    /// Result without file content.
+    pub fn head(uploaded_at: DateTime<Utc>) -> Self {
+        FetchOk {
+            uploaded_at,
+            requested_at: Utc::now(),
+            data: None,
+        }
+    }
+
+    /// Full result.
+    pub fn get(uploaded_at: DateTime<Utc>, data: Vec<u8>) -> Self {
+        FetchOk {
+            uploaded_at,
+            requested_at: Utc::now(),
+            data: Some(data),
+        }
+    }
+}
+
+pub type FetchResult = Result<FetchOk, FetchError>;
+
+pub struct XlsDownloader {
+    pub url: Option<String>,
+}
+
+impl XlsDownloader {
+    pub fn new() -> Self {
+        XlsDownloader { url: None }
+    }
+
+    async fn fetch_specified(url: &str, head: bool) -> FetchResult {
+        let client = reqwest::Client::new();
+
+        let response = if head {
+            client.head(url)
+        } else {
+            client.get(url)
+        }
+        .header("User-Agent", ua_generator::ua::spoof_chrome_ua())
+        .send()
+        .await
+        .map_err(|e| FetchError::unknown(Arc::new(e)))?;
+
+        if response.status().as_u16() != 200 {
+            return Err(FetchError::bad_status_code(response.status().as_u16()));
+        }
+
+        let headers = response.headers();
+
+        let content_type = headers
+            .get("Content-Type")
+            .ok_or(FetchError::bad_headers("Content-Type"))?;
+
+        if !headers.contains_key("etag") {
+            return Err(FetchError::bad_headers("etag"));
+        }
+
+        let last_modified = headers
+            .get("last-modified")
+            .ok_or(FetchError::bad_headers("last-modified"))?;
+
+        if content_type != "application/vnd.ms-excel" {
+            return Err(FetchError::bad_content_type(content_type.to_str().unwrap()));
+        }
+
+        let last_modified = DateTime::parse_from_rfc2822(&last_modified.to_str().unwrap())
+            .unwrap()
+            .with_timezone(&Utc);
+
+        Ok(if head {
+            FetchOk::head(last_modified)
+        } else {
+            FetchOk::get(last_modified, response.bytes().await.unwrap().to_vec())
+        })
+    }
+
+    pub async fn fetch(&self, head: bool) -> FetchResult {
+        if self.url.is_none() {
+            Err(FetchError::NoUrlProvided)
+        } else {
+            Self::fetch_specified(&*self.url.as_ref().unwrap(), head).await
+        }
+    }
+
+    pub async fn set_url(&mut self, url: &str) -> FetchResult {
+        let result = Self::fetch_specified(url, true).await;
+
+        if let Ok(_) = result {
+            self.url = Some(url.to_string());
+        }
+
+        result
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::xls_downloader::{FetchError, XlsDownloader};
+
+    #[tokio::test]
+    async fn bad_url() {
+        let url = "bad_url";
+
+        let mut downloader = XlsDownloader::new();
+        assert!(downloader.set_url(url).await.is_err());
+    }
+
+    #[tokio::test]
+    async fn bad_status_code() {
+        let url = "https://www.google.com/not-found";
+
+        let mut downloader = XlsDownloader::new();
+        assert_eq!(
+            downloader.set_url(url).await,
+            Err(FetchError::bad_status_code(404))
+        );
+    }
+
+    #[tokio::test]
+    async fn bad_headers() {
+        let url = "https://www.google.com/favicon.ico";
+
+        let mut downloader = XlsDownloader::new();
+        assert_eq!(
+            downloader.set_url(url).await,
+            Err(FetchError::BadHeaders {
+                expected_header: "ETag".to_string(),
+            })
+        );
+    }
+
+    #[tokio::test]
+    async fn bad_content_type() {
+        let url = "https://s3.aero-storage.ldragol.ru/679e5d1145a6ad00843ad3f1/67ddb59fd46303008396ac96%2Fexample.txt";
+
+        let mut downloader = XlsDownloader::new();
+        assert!(downloader.set_url(url).await.is_err());
+    }
+
+    #[tokio::test]
+    async fn ok() {
+        let url = "https://s3.aero-storage.ldragol.ru/679e5d1145a6ad00843ad3f1/67ddb5fad46303008396ac97%2Fschedule.xls";
+
+        let mut downloader = XlsDownloader::new();
+        assert!(downloader.set_url(url).await.is_ok());
+    }
+
+    #[tokio::test]
+    async fn downloader_ok() {
+        let url = "https://s3.aero-storage.ldragol.ru/679e5d1145a6ad00843ad3f1/67ddb5fad46303008396ac97%2Fschedule.xls";
+
+        let mut downloader = XlsDownloader::new();
+        assert!(downloader.set_url(url).await.is_ok());
+        assert!(downloader.fetch(false).await.is_ok());
+    }
+
+    #[tokio::test]
+    async fn downloader_no_url_provided() {
+        let downloader = XlsDownloader::new();
+
+        let result = downloader.fetch(false).await;
+        assert_eq!(result, Err(FetchError::NoUrlProvided));
+    }
+}