crabmail

commit 4d2c5c777a587721fb1f91e4e00bad1940cbeebb
parent fd94cdd1382767145420bf09874fa9a201278b61
Author: alex wennerberg <alex@alexwennerberg.com>
Date:   Sat, 22 May 2021 13:03:42 -0700

Clean up escape HTML interface (kinda)

Diffstat:
M
src/main.rs
 | 
29
+++++++++++++++++------------
M
src/utils.rs
 | 
50
++++++++++++++++++++++++++++++--------------------

2 files changed, 47 insertions(+), 32 deletions(-)
diff --git a/src/main.rs b/src/main.rs
@@ -3,6 +3,7 @@ use mailparse::{parse_mail, MailHeaderMap, ParsedMail};
 use std::fs::{File, OpenOptions};
 use std::io::prelude::*;
 use std::path::Path;
+use utils::EscapedHTML;
 
 mod utils;
 
@@ -58,23 +59,27 @@ fn parse_path(s: &std::ffi::OsStr) -> Result<std::path::PathBuf, &'static str> {
 }
 
 fn email_to_html(email: ParsedMail) -> String {
-    // TODO use format strings here i think
-    let escaped_header = |f: &str| {
-        let mut s = String::new();
-        let field = &email.headers.get_first_value(f).unwrap_or("".to_string());
-        utils::escape_html(&mut s, &field);
-        return s;
-    };
+    // Probably if I was better at Rust I could rewrite these in a more efficient way,
+    // avoiding unnecessary allocs. Could use some of the lower-level features of
+    // the mailparse library
+    //
+    // could definitely improve the api here
+    let get_header_alloc = |f| email.headers.get_first_value(f).unwrap_or("".to_string());
 
     return format!(
         r#"
-<b>From<b>: {from}<br>
-<b>Subject</b>: {subject}
+<b>From</b>: {from}<br>
+<b>Subject</b>: {subject}<br>
+<b>Date</b>: {date}<br>
+<b>Message-Id</b>: {message_id}
 <div id="body"> {body} </div>
     "#,
-        from = escaped_header("From"),
-        subject = escaped_header("Subject"),
-        body = &email.get_body().unwrap()
+        from = EscapedHTML(&get_header_alloc("from")),
+        subject = EscapedHTML(&get_header_alloc("subject")),
+        date = EscapedHTML(&get_header_alloc("date")),
+        message_id = EscapedHTML(&get_header_alloc("message-id")),
+        // TODO replace with get body raw to avoid unneeded alloc. same w/ headers
+        body = EscapedHTML(&email.get_body().unwrap_or("".to_string()))
     );
 }
 
diff --git a/src/utils.rs b/src/utils.rs
@@ -1,7 +1,10 @@
+use std::fmt;
 use std::io;
 use std::io::Write;
+
 // Derived from https://github.com/raphlinus/pulldown-cmark/blob/master/src/escape.rs
 // Don't use single quotes (') in any of my attributes
+// Homebrewing my html templating to minimize dependencies
 // !!!WIP!!! -- still need to add tests, audit security, etc
 
 const fn create_html_escape_table() -> [u8; 256] {
@@ -17,27 +20,34 @@ static HTML_ESCAPE_TABLE: [u8; 256] = create_html_escape_table();
 
 static HTML_ESCAPES: [&str; 5] = ["", "&quot;", "&amp;", "&lt;", "&gt;"];
 
-pub fn escape_html(w: &mut String, s: &str) {
-    let bytes = s.as_bytes();
-    let mut mark = 0;
-    let mut i = 0;
-    while i < s.len() {
-        match bytes[i..]
-            .iter()
-            .position(|&c| HTML_ESCAPE_TABLE[c as usize] != 0)
-        {
-            Some(pos) => {
-                i += pos;
+pub struct EscapedHTML<'a>(pub &'a str);
+
+impl fmt::Display for EscapedHTML<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let s = self.0;
+        let bytes = s.as_bytes();
+        let mut mark = 0;
+        let mut i = 0;
+        // does this work
+        while i < s.len() {
+            match bytes[i..]
+                .iter()
+                .position(|&c| HTML_ESCAPE_TABLE[c as usize] != 0)
+            {
+                Some(pos) => {
+                    i += pos;
+                }
+                None => break,
             }
-            None => break,
+            let c = bytes[i];
+            let escape = HTML_ESCAPE_TABLE[c as usize];
+            let escape_seq = HTML_ESCAPES[escape as usize];
+            f.write_str(&s[mark..i])?;
+            f.write_str(escape_seq)?;
+            i += 1;
+            mark = i; // all escaped characters are ASCII
         }
-        let c = bytes[i];
-        let escape = HTML_ESCAPE_TABLE[c as usize];
-        let escape_seq = HTML_ESCAPES[escape as usize];
-        w.push_str(&s[mark..i]);
-        w.push_str(escape_seq);
-        i += 1;
-        mark = i; // all escaped characters are ASCII
+        f.write_str(&s[mark..])?;
+        Ok(())
     }
-    w.push_str(&s[mark..])
 }