Support exporting pem from Certificate

src/imp/openssl.rs

@@ -201,6 +201,11 @@ impl Certificate {
         let der = self.0.to_der()?;
         Ok(der)
     }
+
+    pub fn to_pem(&self) -> Result<Vec<u8>, Error> {
+        let pem = self.0.to_pem()?;
+        Ok(pem)
+    }
 }
 
 pub struct MidHandshakeTlsStream<S>(MidHandshakeSslStream<S>);

src/imp/schannel.rs

@@ -175,6 +175,10 @@ impl Certificate {
     pub fn to_der(&self) -> Result<Vec<u8>, Error> {
         Ok(self.0.to_der().to_vec())
     }
+
+    pub fn to_pem(&self) -> Result<Vec<u8>, Error> {
+        Ok(self.0.to_pem().into_bytes())
+    }
 }
 
 pub struct MidHandshakeTlsStream<S>(tls_stream::MidHandshakeTlsStream<S>);

src/imp/security_framework.rs

@@ -225,6 +225,10 @@ impl Certificate {
     pub fn to_der(&self) -> Result<Vec<u8>, Error> {
         Ok(self.0.to_der())
     }
+
+    pub fn to_pem(&self) -> Result<Vec<u8>, Error> {
+        panic!("Not implemented on macOS/iOS");
+    }
 }
 
 pub enum HandshakeError<S> {

src/lib.rs

@@ -210,6 +210,12 @@ impl Certificate {
         let der = self.0.to_der()?;
         Ok(der)
     }
+
+    /// Returns the PEM-encoded representation of this certificate
+    pub fn to_pem(&self) -> Result<Vec<u8>> {
+        let pem = self.0.to_pem()?;
+        Ok(pem)
+    }
 }
 
 /// A TLS stream which has been interrupted midway through the handshake process.