fix: 修复获取 wbi 签名的 rust 实现 (#1059)

* fix: 修复获取 wbi 签名的 rust 实现

* chore: 在最上面的介绍里补上 Rust 的超链接

docs/misc/sign/wbi.md

@@ -120,7 +120,7 @@
 
 ## Demo
 
-含 [Python](#Python)、[JavaScript](#JavaScript)、[Golang](#Golang)、[C#](#CSharp)、[Java](#Java)、[Swift](#Swift)、[C++](#CPlusPlus) 语言编写的 Demo 。
+含 [Python](#Python)、[JavaScript](#JavaScript)、[Golang](#Golang)、[C#](#CSharp)、[Java](#Java)、[Swift](#Swift)、[C++](#CPlusPlus)、[Rust](#Rust) 语言编写的 Demo 。
 
 ### Python
 
@@ -867,6 +867,7 @@ struct ResWbi {
 fn get_mixin_key(orig: &[u8]) -> String {
     MIXIN_KEY_ENC_TAB
         .iter()
+        .take(32)
         .map(|&i| orig[i] as char)
         .collect::<String>()
 }
@@ -891,23 +892,34 @@ fn get_url_encoded(s: &str) -> String {
 }
 
 // 为请求参数进行 wbi 签名
-fn encode_wbi(params: &mut Vec<(&str, String)>, (img_key, sub_key): (String, String)) -> String {
-    let mixin_key = get_mixin_key((img_key + &sub_key).as_bytes());
+fn encode_wbi(params: Vec<(&str, String)>, (img_key, sub_key): (String, String)) -> String {
     let cur_time = match SystemTime::now().duration_since(UNIX_EPOCH) {
         Ok(t) => t.as_secs(),
         Err(_) => panic!("SystemTime before UNIX EPOCH!"),
     };
+    _encode_wbi(params, (img_key, sub_key), cur_time)
+}
+
+fn _encode_wbi(
+    mut params: Vec<(&str, String)>,
+    (img_key, sub_key): (String, String),
+    timestamp: u64,
+) -> String {
+    let mixin_key = get_mixin_key((img_key + &sub_key).as_bytes());
     // 添加当前时间戳
-    params.push(("wts", cur_time.to_string()));
+    params.push(("wts", timestamp.to_string()));
     // 重新排序
     params.sort_by(|a, b| a.0.cmp(b.0));
-    let query = params.iter().fold(String::from(""), |acc, (k, v)| {
-        acc + format!("{}={}&", get_url_encoded(k), get_url_encoded(v)).as_str()
-    });
-
+    // 拼接参数
+    let query = params
+        .iter()
+        .map(|(k, v)| format!("{}={}", get_url_encoded(k), get_url_encoded(v)))
+        .collect::<Vec<_>>()
+        .join("&");
+    // 计算签名
     let web_sign = format!("{:?}", md5::compute(query.clone() + &mixin_key));
-
-    query + &format!("w_rid={}", web_sign)
+    // 返回最终的 query
+    query + &format!("&w_rid={}", web_sign)
 }
 
 async fn get_wbi_keys() -> Result<(String, String), reqwest::Error> {
@@ -922,23 +934,76 @@ async fn get_wbi_keys() -> Result<(String, String), reqwest::Error> {
     .await?
     .json::<ResWbi>()
     .await?;
+    Ok((
+        take_filename(wbi_img.img_url).unwrap(),
+        take_filename(wbi_img.sub_url).unwrap(),
+    ))
+}
 
-    Ok((wbi_img.img_url, wbi_img.sub_url))
+fn take_filename(url: String) -> Option<String> {
+    url.rsplit_once('/')
+        .and_then(|(_, s)| s.rsplit_once('.'))
+        .map(|(s, _)| s.to_string())
 }
 
 #[tokio::main]
 async fn main() {
-    let urls = get_wbi_keys().await.unwrap();
-    let mut params = vec![
+    let keys = get_wbi_keys().await.unwrap();
+    let params = vec![
         ("foo", String::from("114")),
         ("bar", String::from("514")),
         ("baz", String::from("1919810")),
     ];
-
-    let query = encode_wbi(&mut params, urls);
-
+    let query = encode_wbi(params, keys);
     println!("{}", query);
 }
+
+// 取自文档描述的测试用例
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_get_filename() {
+        assert_eq!(
+            take_filename(
+                "https://i0.hdslb.com/bfs/wbi/7cd084941338484aae1ad9425b84077c.png".to_string()
+            ),
+            Some("7cd084941338484aae1ad9425b84077c".to_string())
+        );
+    }
+
+    #[test]
+    fn test_get_mixin_key() {
+        let concat_key =
+            "7cd084941338484aae1ad9425b84077c".to_string() + "4932caff0ff746eab6f01bf08b70ac45";
+        assert_eq!(
+            get_mixin_key(concat_key.as_bytes()),
+            "ea1db124af3c7062474693fa704f4ff8"
+        );
+    }
+
+    #[test]
+    fn test_encode_wbi() {
+        let params = vec![
+            ("foo", String::from("114")),
+            ("bar", String::from("514")),
+            ("zab", String::from("1919810")),
+        ];
+        assert_eq!(
+            _encode_wbi(
+                params,
+                (
+                    "7cd084941338484aae1ad9425b84077c".to_string(),
+                    "4932caff0ff746eab6f01bf08b70ac45".to_string()
+                ),
+                1702204169
+            ),
+            "bar=514&foo=114&wts=1702204169&zab=1919810&w_rid=8f6f2b5b3d485fe1886cec6a0be8c5d4"
+                .to_string()
+        )
+    }
+}
 ```
 
 ### Swift