[#1095]: Implement basic_auth for WASM

Signed-off-by: Jens Reimann <jreimann@redhat.com>

src/wasm/request.rs

@@ -1,6 +1,8 @@
 use std::convert::TryFrom;
 use std::fmt;
+use std::io::Write;
 
+use base64::write::EncoderWriter as Base64Encoder;
 use bytes::Bytes;
 use http::{request::Parts, Method, Request as HttpRequest};
 use serde::Serialize;
@@ -206,6 +208,25 @@ impl RequestBuilder {
         self
     }
 
+    /// Enable HTTP basic authentication.
+    pub fn basic_auth<U, P>(self, username: U, password: Option<P>) -> RequestBuilder
+    where
+        U: fmt::Display,
+        P: fmt::Display,
+    {
+        let mut header_value = b"Basic ".to_vec();
+        {
+            let mut encoder = Base64Encoder::new(&mut header_value, base64::STANDARD);
+            // The unwraps here are fine because Vec::write* is infallible.
+            write!(encoder, "{}:", username).unwrap();
+            if let Some(password) = password {
+                write!(encoder, "{}", password).unwrap();
+            }
+        }
+
+        self.header(crate::header::AUTHORIZATION, header_value)
+    }
+
     /// Enable HTTP bearer authentication.
     pub fn bearer_auth<T>(self, token: T) -> RequestBuilder
     where