2 files changed, 73 insertions, 1 deletions
diff --git a/src/transaction/auth.rs b/src/transaction/auth.rs
new file mode 100644
index 0000000..f64bb4b
--- /dev/null
+++ b/src/transaction/auth.rs
@@ -0,0 +1,51 @@
+use crate::encoding::{
+    headers::{Authorization, WWWAuthenticate},
+    method::Method,
+    request::Request,
+    response::Response,
+    uri::Uri,
+};
+use anyhow::Result;
+
+impl Authorization {
+    pub fn construct(
+        request: &Request,
+        failed_response: &Response,
+        username: &str,
+        password: &str,
+    ) -> Result<Authorization> {
+        let challenge = failed_response.headers.get::<WWWAuthenticate>().unwrap()?;
+
+        Ok(Authorization {
+            response: response_digest(
+                username.to_string(),
+                challenge.realm.clone(),
+                password.to_string(),
+                request.method,
+                challenge.nonce.clone(),
+                request.uri.clone(),
+            ),
+            nonce: challenge.nonce,
+            realm: challenge.realm,
+            uri: request.uri.content.clone(),
+            username: username.to_string(),
+        })
+    }
+}
+
+fn response_digest(
+    username: String,
+    realm: String,
+    password: String,
+    method: Method,
+    nonce: String,
+    uri: Uri,
+) -> String {
+    let h = |s: String| hex::encode(md5::compute(s.as_bytes()).0);
+    let kd = |secret, data| h(format!("{secret}:{data}"));
+
+    let a1 = format!("{username}:{realm}:{password}");
+    let a2 = format!("{method}:{uri}");
+    let response_digest = kd(h(a1), format!("{nonce}:{}", h(a2)));
+    return response_digest;
+}
diff --git a/src/transaction/mod.rs b/src/transaction/mod.rs
index 3be9544..601b134 100644
--- a/src/transaction/mod.rs
+++ b/src/transaction/mod.rs
@@ -1,5 +1,12 @@
+pub mod auth;
+
 use crate::{
-    encoding::{headers::CSeq, request::Request, response::Response, Message},
+    encoding::{
+        headers::{CSeq, CallID},
+        request::Request,
+        response::Response,
+        Message,
+    },
     transport::Transport,
 };
 use anyhow::{anyhow, Result};
@@ -48,6 +55,20 @@ impl<T: Transport> TransactionUser<T> {
             }
         }
     }
+    pub async fn respond(&self, req: &Request, mut resp: Response) -> Result<()> {
+        resp.headers.insert(
+            req.headers
+                .get::<CSeq>()
+                .ok_or(anyhow!("cseq is mandatory"))??,
+        );
+        resp.headers.insert(
+            req.headers
+                .get::<CallID>()
+                .ok_or(anyhow!("call-id is mandatory"))??,
+        );
+        self.transport.send(Message::Response(resp)).await?;
+        Ok(())
+    }
 
     pub async fn transact(&self, mut request: Request) -> Result<mpsc::Receiver<Response>> {
         let seq = self.sequence.fetch_add(1, Ordering::Relaxed);