add hop_info (#2751)

src/dc_tools.rs

@@ -5,6 +5,7 @@ use core::cmp::{max, min};
 use std::borrow::Cow;
 use std::fmt;
 use std::io::Cursor;
+use std::str::from_utf8;
 use std::str::FromStr;
 use std::time::{Duration, SystemTime};
 
@@ -14,6 +15,9 @@ use async_std::{fs, io};
 
 use anyhow::{bail, Error};
 use chrono::{Local, TimeZone};
+use mailparse::dateparse;
+use mailparse::headers::Headers;
+use mailparse::MailHeaderMap;
 use rand::{thread_rng, Rng};
 
 use crate::chat::{add_device_msg, add_device_msg_with_importance};
@@ -670,13 +674,126 @@ pub fn remove_subject_prefix(last_subject: &str) -> String {
         .to_string()
 }
 
+// Types and methods to create hop-info for message-info
+
+fn extract_address_from_receive_header<'a>(header: &'a str, start: &str) -> Option<&'a str> {
+    let header_len = header.len();
+    header.find(start).and_then(|mut begin| {
+        begin += start.len();
+        let end = header
+            .get(begin..)?
+            .find(|c: char| c.is_whitespace())
+            .unwrap_or(header_len);
+        header.get(begin..begin + end)
+    })
+}
+
+pub(crate) fn parse_receive_header(header: &str) -> String {
+    let header = header.replace(&['\r', '\n'][..], "");
+    let mut hop_info = String::from("Hop: ");
+
+    if let Some(from) = extract_address_from_receive_header(&header, "from ") {
+        hop_info += &format!("From: {}; ", from.trim());
+    }
+
+    if let Some(by) = extract_address_from_receive_header(&header, "by ") {
+        hop_info += &format!("By: {}; ", by.trim());
+    }
+
+    if let Ok(date) = dateparse(&header) {
+        // In tests, use the UTC timezone so that the test is reproducible
+        #[cfg(test)]
+        let date_obj = chrono::Utc.timestamp(date, 0);
+        #[cfg(not(test))]
+        let date_obj = Local.timestamp(date, 0);
+
+        hop_info += &format!("Date: {}", date_obj.to_rfc2822());
+    };
+
+    hop_info
+}
+
+/// parses "receive"-headers
+pub(crate) fn parse_receive_headers(headers: &Headers) -> String {
+    headers
+        .get_all_headers("Received")
+        .iter()
+        .rev()
+        .filter_map(|header_map_item| from_utf8(header_map_item.get_value_raw()).ok())
+        .map(parse_receive_header)
+        .collect::<Vec<_>>()
+        .join("\n")
+}
+
 #[cfg(test)]
 mod tests {
     #![allow(clippy::indexing_slicing)]
 
     use super::*;
 
-    use crate::test_utils::TestContext;
+    use crate::{
+        config::Config, dc_receive_imf::dc_receive_imf, message::get_msg_info,
+        test_utils::TestContext,
+    };
+
+    #[test]
+    fn test_parse_receive_headers() {
+        // Test `parse_receive_headers()` with some more-or-less random emails from the test-data
+        let raw = include_bytes!("../test-data/message/mail_with_cc.txt");
+        let expected =
+            "Hop: From: localhost; By: hq5.merlinux.eu; Date: Sat, 14 Sep 2019 17:00:22 +0000\n\
+             Hop: From: hq5.merlinux.eu; By: hq5.merlinux.eu; Date: Sat, 14 Sep 2019 17:00:25 +0000";
+        check_parse_receive_headers(raw, expected);
+
+        let raw = include_bytes!("../test-data/message/wrong-html.eml");
+        let expected =
+            "Hop: From: oxbsltgw18.schlund.de; By: mrelayeu.kundenserver.de; Date: Thu, 06 Aug 2020 16:40:31 +0000\n\
+             Hop: From: mout.kundenserver.de; By: dd37930.kasserver.com; Date: Thu, 06 Aug 2020 16:40:32 +0000";
+        check_parse_receive_headers(raw, expected);
+
+        let raw = include_bytes!("../test-data/message/posteo_ndn.eml");
+        let expected =
+            "Hop: By: mout01.posteo.de; Date: Tue, 09 Jun 2020 18:44:22 +0000\n\
+             Hop: From: mout01.posteo.de; By: mx04.posteo.de; Date: Tue, 09 Jun 2020 18:44:22 +0000\n\
+             Hop: From: mx04.posteo.de; By: mailin06.posteo.de; Date: Tue, 09 Jun 2020 18:44:23 +0000\n\
+             Hop: From: mailin06.posteo.de; By: proxy02.posteo.de; Date: Tue, 09 Jun 2020 18:44:23 +0000\n\
+             Hop: From: proxy02.posteo.de; By: proxy02.posteo.name; Date: Tue, 09 Jun 2020 18:44:23 +0000\n\
+             Hop: From: proxy02.posteo.name; By: dovecot03.posteo.local; Date: Tue, 09 Jun 2020 18:44:24 +0000";
+        check_parse_receive_headers(raw, expected);
+    }
+
+    fn check_parse_receive_headers(raw: &[u8], expected: &str) {
+        let mail = mailparse::parse_mail(raw).unwrap();
+        let hop_info = parse_receive_headers(&mail.get_headers());
+        assert_eq!(hop_info, expected)
+    }
+
+    #[async_std::test]
+    async fn test_parse_receive_headers_integration() -> anyhow::Result<()> {
+        let t = TestContext::new_alice().await;
+        t.set_config(Config::ShowEmails, Some("2")).await?;
+        let raw = include_bytes!("../test-data/message/mail_with_cc.txt");
+        dc_receive_imf(&t, raw, "INBOX", 1, false).await.unwrap();
+        let g = t.get_last_msg().await;
+
+        let expected = r"State: Fresh
+
+hi
+
+Message-ID: 2dfdbde7@example.org
+Last seen as: INBOX/1
+
+Hop: From: localhost; By: hq5.merlinux.eu; Date: Sat, 14 Sep 2019 17:00:22 +0000
+Hop: From: hq5.merlinux.eu; By: hq5.merlinux.eu; Date: Sat, 14 Sep 2019 17:00:25 +0000";
+        let result = get_msg_info(&t, g.id).await.unwrap();
+        // little hack to ignore the first row of a parsed email because it contains a
+        // send time that depends and the test runtime which makes it impossible to
+        // compare with a static string
+        let capped_result = &result[result.find("State").unwrap()..];
+
+        assert_eq!(expected, capped_result);
+        Ok(())
+    }
 
     #[test]
     fn test_rust_ftoa() {