Fix decoding of form value Strings.

examples/forms/src/main.rs

@@ -12,7 +12,7 @@ use rocket::response::Redirect;
 #[derive(FromForm)]
 struct UserLogin<'r> {
     username: &'r str,
-    password: &'r str,
+    password: String,
     age: Result<usize, &'r str>,
 }
 
@@ -27,7 +27,7 @@ fn login<'a>(user_form: Form<'a, UserLogin<'a>>) -> Result<Redirect, String> {
     };
 
     if user.username == "Sergio" {
-        match user.password {
+        match user.password.as_str() {
             "password" => Ok(Redirect::to("/user/Sergio")),
             _ => Err("Wrong password!".to_string())
         }

lib/src/request/form/from_form_value.rs

@@ -73,21 +73,11 @@ impl<'v> FromFormValue<'v> for String {
 
     // This actually parses the value according to the standard.
     fn from_form_value(v: &'v str) -> Result<Self, Self::Error> {
-        let result = URI::percent_decode(v.as_bytes());
+        let replaced = v.replace("+", " ");
+        let result = URI::percent_decode(replaced.as_bytes());
         match result {
             Err(_) => Err(v),
-            Ok(mut string) => Ok({
-                // Entirely safe because we're changing the single-byte '+'.
-                unsafe {
-                    for c in string.to_mut().as_mut_vec() {
-                        if *c == b'+' {
-                            *c = b' ';
-                        }
-                    }
-                }
-
-                string.into_owned()
-            })
+            Ok(string) => Ok(string.into_owned())
         }
     }
 }

lib/tests/form_method-issue-45.rs

@@ -42,6 +42,6 @@ fn get_passes_through() {
         .header(ContentType::Form)
         .body("_method=patch&form_data=Form+data");
 
-    let mut response = req.dispatch_with(&rocket);
+    let response = req.dispatch_with(&rocket);
     assert_eq!(response.status(), Status::NotFound);
 }

lib/tests/form_value_decoding-issue-82.rs

@@ -0,0 +1,45 @@
+#![feature(plugin, custom_derive)]
+#![plugin(rocket_codegen)]
+
+extern crate rocket;
+
+use rocket::request::Form;
+
+#[derive(FromForm)]
+struct FormData {
+    form_data: String,
+}
+
+#[post("/", data = "<form_data>")]
+fn bug(form_data: Form<FormData>) -> String {
+    form_data.into_inner().form_data
+}
+
+use rocket::testing::MockRequest;
+use rocket::http::Method::*;
+use rocket::http::ContentType;
+use rocket::http::Status;
+
+fn check_decoding(raw: &str, decoded: &str) {
+    let rocket = rocket::ignite().mount("/", routes![bug]);
+
+    let mut req = MockRequest::new(Post, "/")
+        .header(ContentType::Form)
+        .body(format!("form_data={}", raw));
+
+    let mut response = req.dispatch_with(&rocket);
+    let body_string = response.body().and_then(|b| b.into_string());
+    assert_eq!(response.status(), Status::Ok);
+    assert_eq!(Some(decoded.to_string()), body_string);
+}
+
+#[test]
+fn test_proper_decoding() {
+    check_decoding("password", "password");
+    check_decoding("", "");
+    check_decoding("+", " ");
+    check_decoding("%2B", "+");
+    check_decoding("1+1", "1 1");
+    check_decoding("1%2B1", "1+1");
+    check_decoding("%3Fa%3D1%26b%3D2", "?a=1&b=2");
+}