Detect encoding in Response::text() (#256)

* Detect encoding and decode text response

Fixes #246

* Try to get encoding from Content-Type header

* Remove uchardet encoding detection for now

* Add non utf-8 test case for Response::text()

* Reduce copies

Cargo.toml

@@ -11,6 +11,7 @@ categories = ["web-programming::http-client"]
 
 [dependencies]
 bytes = "0.4"
+encoding_rs = "0.7"
 futures = "0.1.15"
 hyper = "0.11.9"
 hyper-tls = "0.1.2"

src/lib.rs

@@ -129,6 +129,7 @@
 //! [cookiejar_issue]: https://github.com/seanmonstar/reqwest/issues/14
 
 extern crate bytes;
+extern crate encoding_rs;
 #[macro_use]
 extern crate futures;
 extern crate hyper;

src/response.rs

@@ -2,7 +2,9 @@ use std::mem;
 use std::fmt;
 use std::io::{self, Read};
 use std::time::Duration;
+use std::borrow::Cow;
 
+use encoding_rs::{Encoding, UTF_8};
 use futures::{Async, Poll, Stream};
 use serde::de::DeserializeOwned;
 use serde_json;
@@ -167,6 +169,11 @@ impl Response {
 
     /// Get the response text.
     ///
+    /// This method decodes the response body with BOM sniffing
+    /// and with malformed sequences replaced with the REPLACEMENT CHARACTER.
+    /// Encoding is determinated from the `charset` parameter of `Content-Type` header,
+    /// and defaults to `utf-8` if not presented.
+    ///
     /// # Example
     ///
     /// ```rust
@@ -180,9 +187,28 @@ impl Response {
         let len = self.headers().get::<::header::ContentLength>()
             .map(|ct_len| **ct_len)
             .unwrap_or(0);
-        let mut content = String::with_capacity(len as usize);
-        self.read_to_string(&mut content).map_err(::error::from)?;
-        Ok(content)
+        let mut content = Vec::with_capacity(len as usize);
+        self.read_to_end(&mut content).map_err(::error::from)?;
+        let encoding_name = self.headers().get::<::header::ContentType>()
+            .and_then(|content_type| {
+                content_type.get_param("charset")
+                    .map(|charset| charset.as_str())
+            })
+            .unwrap_or("utf-8");
+        let encoding = Encoding::for_label(encoding_name.as_bytes()).unwrap_or(UTF_8);
+        // a block because of borrow checker
+        {
+            let (text, _, _) = encoding.decode(&content);
+            match text {
+                Cow::Owned(s) => return Ok(s),
+                _ => (),
+            }
+        }
+        unsafe {
+            // decoding returned Cow::Borrowed, meaning these bytes
+            // are already valid utf8
+            Ok(String::from_utf8_unchecked(content))
+        }
     }
 
     /// Copy the response body into a writer.

tests/client.rs

@@ -38,6 +38,41 @@ fn test_response_text() {
     assert_eq!(b"Hello", body.as_bytes());
 }
 
+#[test]
+fn test_response_non_utf_8_text() {
+    let server = server! {
+        request: b"\
+            GET /text HTTP/1.1\r\n\
+            Host: $HOST\r\n\
+            User-Agent: $USERAGENT\r\n\
+            Accept: */*\r\n\
+            Accept-Encoding: gzip\r\n\
+            \r\n\
+            ",
+        response: b"\
+            HTTP/1.1 200 OK\r\n\
+            Server: test\r\n\
+            Content-Length: 4\r\n\
+            Content-Type: text/plain; charset=gbk\r\n\
+            \r\n\
+            \xc4\xe3\xba\xc3\
+            "
+    };
+
+    let url = format!("http://{}/text", server.addr());
+    let mut res = reqwest::get(&url).unwrap();
+    assert_eq!(res.url().as_str(), &url);
+    assert_eq!(res.status(), reqwest::StatusCode::Ok);
+    assert_eq!(res.headers().get(),
+               Some(&reqwest::header::Server::new("test".to_string())));
+    assert_eq!(res.headers().get(),
+               Some(&reqwest::header::ContentLength(4)));
+
+    let body = res.text().unwrap();
+    assert_eq!("你好", &body);
+    assert_eq!(b"\xe4\xbd\xa0\xe5\xa5\xbd", body.as_bytes());  // Now it's utf-8
+}
+
 #[test]
 fn test_response_copy_to() {
     let server = server! {