Redact authorization header from debug logging outputs

Author: seratch

slack-api-client/src/main/java/com/slack/api/util/http/listener/DetailedLoggingListener.java

@@ -1,11 +1,17 @@
 package com.slack.api.util.http.listener;
 
 import lombok.extern.slf4j.Slf4j;
+import okhttp3.Headers;
 import okhttp3.RequestBody;
 import okhttp3.Response;
 import okio.Buffer;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
+
+import static java.util.stream.Collectors.joining;
 
 /**
  * An HTTP response listener that prints the details of request/response mainly for debugging purposes.
@@ -43,6 +49,18 @@ public void accept(State state) {
                 log.error("Failed to read the content length because {}", e.getMessage(), e);
             }
 
+            Headers originalRequestHeaders = response.request().headers();
+            List<String> requestHeaders = new ArrayList<>();
+            for (String headerName : originalRequestHeaders.names()) {
+                if (headerName.toLowerCase(Locale.ENGLISH).equals("authorization")
+                        && !state.getConfig().isLibraryMaintainerMode()) {
+                    requestHeaders.add(headerName + ": (redacted)");
+                } else {
+                    requestHeaders.add(headerName + ": " + originalRequestHeaders.get(headerName));
+                }
+            }
+            String requestHeaderLines = requestHeaders.stream().collect(joining("\n")) + "\n";
+
             log.debug("\n[Request URL]\n{} {}\n" +
                             "[Specified Request Headers]\n{}" +
                             "[Request Body]\n{}\n\n" +
@@ -54,7 +72,7 @@ public void accept(State state) {
                             "[Response Body]\n{}\n",
                     response.request().method(),
                     response.request().url(),
-                    response.request().headers(),
+                    requestHeaderLines,
                     textRequestBody,
                     requestBodyObj != null ? requestBodyObj.contentType() : null,
                     contentLength,