From 661f97a073bf0aa4d17c8cb3c5a47cf603e5e910 Mon Sep 17 00:00:00 2001
From: Rens Groothuijsen <l.groothuijsen@alumni.maastrichtuniversity.nl>
Date: Thu, 6 Jan 2022 14:13:17 +0100
Subject: [PATCH] Use correct encoding when fetching non-UTF-8 site metadata
 (#2015)

* Use correct encoding when fetching non-UTF-8 site metadata

* Style fixes
---
 crates/utils/Cargo.toml     |  1 +
 crates/utils/src/request.rs | 25 ++++++++++++++++++++-----
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/crates/utils/Cargo.toml b/crates/utils/Cargo.toml
index a8c35a06..894ae0c1 100644
--- a/crates/utils/Cargo.toml
+++ b/crates/utils/Cargo.toml
@@ -45,3 +45,4 @@ webpage = { version = "1.4.0", default-features = false, features = ["serde"] }
 jsonwebtoken = "7.2.0"
 doku = "0.10.2"
 uuid = { version = "0.8.2", features = ["serde", "v4"] }
+encoding = "0.2.33"
\ No newline at end of file
diff --git a/crates/utils/src/request.rs b/crates/utils/src/request.rs
index 081eaa2b..6af360a5 100644
--- a/crates/utils/src/request.rs
+++ b/crates/utils/src/request.rs
@@ -1,5 +1,6 @@
 use crate::{settings::structs::Settings, version::VERSION, LemmyError};
 use anyhow::anyhow;
+use encoding::{all::encodings, DecoderTrap};
 use percent_encoding::{utf8_percent_encode, NON_ALPHANUMERIC};
 use reqwest_middleware::ClientWithMiddleware;
 use serde::{Deserialize, Serialize};
@@ -75,16 +76,17 @@ pub async fn fetch_site_metadata(
     .map_err(|e| RecvError(e.to_string()))?
     .to_vec();
 
-  let html = String::from_utf8_lossy(&html_bytes);
-
-  let tags = html_to_site_metadata(&html)?;
+  let tags = html_to_site_metadata(&html_bytes)?;
 
   Ok(tags)
 }
 
-fn html_to_site_metadata(html: &str) -> Result<SiteMetadata, LemmyError> {
+fn html_to_site_metadata(html_bytes: &[u8]) -> Result<SiteMetadata, LemmyError> {
+  let html = String::from_utf8_lossy(html_bytes);
+
   // Make sure the first line is doctype html
   let first_line = html
+    .trim_start()
     .lines()
     .into_iter()
     .next()
@@ -97,7 +99,20 @@ fn html_to_site_metadata(html: &str) -> Result<SiteMetadata, LemmyError> {
     ));
   }
 
-  let page = HTML::from_string(html.to_string(), None)?;
+  let mut page = HTML::from_string(html.to_string(), None)?;
+
+  // If the web page specifies that it isn't actually UTF-8, re-decode the received bytes with the
+  // proper encoding. If the specified encoding cannot be found, fall back to the original UTF-8
+  // version.
+  if let Some(charset) = page.meta.get("charset") {
+    if charset.to_lowercase() != "utf-8" {
+      if let Some(encoding_ref) = encodings().iter().find(|e| e.name() == charset) {
+        if let Ok(html_with_encoding) = encoding_ref.decode(html_bytes, DecoderTrap::Replace) {
+          page = HTML::from_string(html_with_encoding, None)?;
+        }
+      }
+    }
+  }
 
   let page_title = page.title;
   let page_description = page.description;
-- 
2.44.1