Move lower casing of headers from parser to valve

conf/server.xml

@@ -160,6 +160,9 @@
                resourceName="UserDatabase"/>
       </Realm>
 
+      <!-- LowerCaseHeaders valve makes http headers case insensitive, but retains original spelling --> 
+      <Valve className="org.apache.catalina.valves.LowerCaseHeadersValve" />
+
       <Host name="localhost"  appBase="webapps"
             unpackWARs="true" autoDeploy="true">
 

java/org/apache/catalina/valves/LowerCaseHeadersValve.java

@@ -0,0 +1,57 @@
+package org.apache.catalina.valves;
+
+import org.apache.catalina.connector.Response;
+import org.apache.catalina.valves.ValveBase;
+import org.apache.tomcat.util.buf.MessageBytes;
+import org.apache.tomcat.util.http.MimeHeaders;
+
+import javax.servlet.ServletException;
+import java.io.IOException;
+import java.util.*;
+
+import org.apache.juli.logging.Log;
+import org.apache.juli.logging.LogFactory;
+
+public class LowerCaseHeadersValve extends ValveBase {
+	private static final Log log = LogFactory.getLog(LowerCaseHeadersValve.class);
+
+    @Override
+    public void invoke(org.apache.catalina.connector.Request request, Response response) throws IOException, ServletException {
+		log.debug("in");
+        // Access the Coyote request (Tomcat's internal request object)
+        org.apache.coyote.Request coyoteRequest = request.getCoyoteRequest();
+        MimeHeaders mimeHeaders = coyoteRequest.getMimeHeaders();
+
+        // Preserve original header names with case
+        Map<String, List<String>> originalHeaders = new LinkedHashMap<>();
+
+        for (int i = 0; i < mimeHeaders.size(); i++) {
+            MessageBytes nameMessageBytes = mimeHeaders.getName(i);
+            MessageBytes valueMessageBytes = mimeHeaders.getValue(i);
+
+            String name = nameMessageBytes.toString();
+            String value = valueMessageBytes.toString();
+
+			if(log.isDebugEnabled()) {
+				log.debug("raw: "+name+": "+value);
+			}
+
+            originalHeaders.computeIfAbsent(name, k -> new ArrayList<>()).add(value);
+
+			nameMessageBytes.setString(name.toLowerCase());
+
+			if(log.isDebugEnabled()) {
+            	name = nameMessageBytes.toString();
+            	value = valueMessageBytes.toString();
+				log.debug("current: "+name+": "+value);
+			}
+        }
+
+        // Store headers in request attributes for downstream use
+        request.setAttribute("originalHeaders", originalHeaders);
+
+        // Continue pipeline
+        getNext().invoke(request, response);
+    }
+}
+

java/org/apache/coyote/http11/Http11InputBuffer.java

@@ -906,11 +906,6 @@ private HeaderParseStatus parseHeader() throws IOException {
                 // skipLine() will handle the error
                 return skipLine(false);
             }
-
-            // chr is next byte of header name. Convert to lowercase.
-            if (chr >= Constants.A && chr <= Constants.Z) {
-                byteBuffer.put(pos, (byte) (chr - Constants.LC_OFFSET));
-            }
         }
 
         // Skip the line and ignore the header