Reflecting the case-insensitivity of http headers

example/app-model/src/test/java/com/mastercard/test/flow/example/app/model/ExampleSystemTest.java

@@ -56,7 +56,7 @@ void messageHashes() {
 
 		mh.expect( ExampleSystem.MODEL,
 				"ALL MESSAGES",
-				"D1FA41700482366067D91A38D0C4E233 0122 21.3 KiB",
+				"FD907B745292C2C0980111694D69A8E8 0122 21.3 KiB",
 				"REQUESTS --> USER",
 				"00000000000000000000000000000000 0000 0 B",
 				"RESPONSES <-- USER",
@@ -70,29 +70,29 @@ void messageHashes() {
 				"RESPONSES <-- WEB_UI",
 				"7F6603B1CDD0593C7CF9771790C07911 0002 151 B",
 				"REQUESTS --> UI",
-				"323C8E3297DC898D2793EDDF60D8C5EC 0014 1.9 KiB",
+				"7B274E372CB060D8AD2E171A1308684D 0014 1.9 KiB",
 				"RESPONSES <-- UI",
-				"A670C078235AEB12636A0D130438A0BF 0014 2.6 KiB",
+				"2A8921FF7B8A91F7503AD3A6CD8F11D6 0014 2.6 KiB",
 				"REQUESTS --> CORE",
-				"681B2BB38FB90027F44C8467727F8D58 0015 2.3 KiB",
+				"1DF594DDAA7A732ED57E86BBF5A46348 0015 2.3 KiB",
 				"RESPONSES <-- CORE",
-				"11BFA337817BB5B4C8AE414F410F271E 0015 3.7 KiB",
+				"D4A0C1DF9D0851FE08B0D622C9A911C9 0015 3.7 KiB",
 				"REQUESTS --> QUEUE",
-				"3A79459ABD8CA52EA136B5DC00F15787 0007 975 B",
+				"CB06D74485A51EE84AA11C58B7BBE764 0007 975 B",
 				"RESPONSES <-- QUEUE",
-				"63C8D46EC4602B3FDC93973FCC286190 0007 1.3 KiB",
+				"C4D61888FE5F3D71D0A2EBCF9894CAC8 0007 1.3 KiB",
 				"REQUESTS --> STORE",
-				"A01276774007C68063E237FE73FC1C95 0006 939 B",
+				"774BC6DDD7772EE419E8705E1A0BBA34 0006 939 B",
 				"RESPONSES <-- STORE",
-				"50EF3C22818B95725B78A802470AD28B 0006 1.1 KiB",
+				"3DD66292776363BB0FC0E5F2443DDD7C 0006 1.1 KiB",
 				"REQUESTS --> DB",
 				"A06D030C1A8192CFE446CD5893217196 0008 2.6 KiB",
 				"RESPONSES <-- DB",
 				"3F7C757B6981B4A5844357C399720641 0008 1.1 KiB",
 				"REQUESTS --> HISTOGRAM",
-				"51B9735B70AE590E97230E245263CC7B 0009 1.1 KiB",
+				"BF8DDDB8D319B876FADD333BCB149E4F 0009 1.1 KiB",
 				"RESPONSES <-- HISTOGRAM",
-				"4C0832B1D6CB88891B5D6C902D35F7B1 0009 1.6 KiB" );
+				"1744EA709AEE2A8718AE343B15C399BC 0009 1.6 KiB" );
 	}
 
 	/**

message/message-http/src/main/java/com/mastercard/test/flow/msg/http/HttpMsg.java

@@ -175,7 +175,7 @@ public byte[] content() {
 	 * @return The complete formatted body
 	 */
 	protected String enchunken( String content, boolean wire ) {
-		if( wire && "chunked".equals( get( header( "Transfer-Encoding" ) ) ) ) {
+		if( wire && "chunked".equals( get( header( "transfer-encoding" ) ) ) ) {
 			return String.format( ""
 					+ "%s\r\n" // chunk length
 					+ "%s\r\n" // chunk
@@ -196,7 +196,7 @@ protected String enchunken( String content, boolean wire ) {
 	 * @return The actual content
 	 */
 	protected String dechunken( String chunked ) {
-		if( "chunked".equals( get( header( "Transfer-Encoding" ) ) ) ) {
+		if( "chunked".equals( get( header( "transfer-encoding" ) ) ) ) {
 			StringBuilder unchunked = new StringBuilder();
 			String input = "\r\n" + chunked; // so we can catch the first chunk with our regex
 			Matcher m = chunkLength.matcher( input );
@@ -248,16 +248,24 @@ protected static boolean isHeaderField( String field ) {
 	}
 
 	/**
+	 * Creates a header field name. Note that
+	 * <a href="https://www.rfc-editor.org/rfc/rfc9110.html#name-field-names">header
+	 * fields are case-insensitive</a>. Accordingly, this method will convert the
+	 * supplied name to lower-case before adding the sigils that identify it as a
+	 * header field.
+	 *
 	 * @param name The desired header name
 	 * @return The value to pass as the field name in {@link #set(String, Object)}
 	 *         and {@link #get(String)}
 	 */
 	public static String header( String name ) {
-		return HEADER_PRESUFIX + name + HEADER_PRESUFIX;
+		return HEADER_PRESUFIX + name.toLowerCase() + HEADER_PRESUFIX;
 	}
 
 	/**
-	 * The inverse of {@link #header(String)}
+	 * The inverse of {@link #header(String)}. Bear in mind that
+	 * {@link #header(String)} lower-casing behaviour is a destructive operation, so
+	 * the inversion might not be perfect.
 	 *
 	 * @param name The value returned from {@link #header(String)}
 	 * @return The value passed to that invocation of {@link #header(String)}

message/message-http/src/main/java/com/mastercard/test/flow/msg/http/HttpReq.java

@@ -75,8 +75,7 @@ public HttpReq( byte[] content, Function<byte[], Message> bodyParse ) {
 		while( !lines.isEmpty() && !(headerLine = lines.removeFirst()).isEmpty() ) {
 			Matcher h = HEADER_LINE_PATTERN.matcher( headerLine );
 			if( h.matches() ) {
-				set( HEADER_PRESUFIX + h.group( "name" ).trim() + HEADER_PRESUFIX,
-						h.group( "value" ).trim() );
+				set( header( h.group( "name" ).trim() ), h.group( "value" ).trim() );
 			}
 		}
 

message/message-http/src/main/java/com/mastercard/test/flow/msg/http/HttpRes.java

@@ -66,7 +66,7 @@ public HttpRes( byte[] content, Function<byte[], Message> bodyParse ) {
 		while( !lines.isEmpty() && !(headerLine = lines.removeFirst()).isEmpty() ) {
 			Matcher h = HEADER_LINE_PATTERN.matcher( headerLine );
 			if( h.matches() ) {
-				set( HEADER_PRESUFIX + h.group( "name" ).trim() + HEADER_PRESUFIX,
+				set( header( h.group( "name" ).trim() ),
 						h.group( "value" ).trim() );
 			}
 		}

message/message-http/src/test/java/com/mastercard/test/flow/msg/http/HttpMsgTest.java

@@ -0,0 +1,24 @@
+package com.mastercard.test.flow.msg.http;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Exercises generic functionality of the {@link HttpMsg} superclass
+ */
+@SuppressWarnings("static-method")
+class HttpMsgTest {
+
+	/**
+	 * Illustrates the lower-casing behaviour of {@link HttpMsg#header(String)}
+	 */
+	@Test
+	void header() {
+		assertEquals( "^mixed-case^", HttpMsg.header( "MiXeD-cAsE" ),
+				"name is lower-cased and sigils are added" );
+
+		assertEquals( "mixed-case", HttpMsg.unheader( HttpMsg.header( "MiXeD-cAsE" ) ),
+				"unheader cannot restore the input casing" );
+	}
+}

message/message-http/src/test/java/com/mastercard/test/flow/msg/http/HttpReqTest.java

@@ -241,7 +241,7 @@ void chunked() {
 
 		assertEquals( ""
 				+ "GET /foo/bar HTTP/1.1\r\n"
-				+ "Transfer-Encoding: chunked\r\n"
+				+ "transfer-encoding: chunked\r\n"
 				+ "\r\n"
 				+ "{\n"
 				+ "  \"body\" : \"content\"\n"
@@ -250,7 +250,7 @@ void chunked() {
 
 		assertEquals( ""
 				+ "GET /foo/bar HTTP/1.1\r\n"
-				+ "Transfer-Encoding: chunked\r\n"
+				+ "transfer-encoding: chunked\r\n"
 				+ "\r\n"
 				+ "12\r\n" // remember this is hex
 				+ "{\"body\":\"content\"}\r\n"
@@ -295,7 +295,7 @@ void masking() {
 
 		assertEquals( ""
 				+ "GET /foo/_mp_/bar?q=_mq_&r=_mr_ HTTP/1.1\r\n"
-				+ "Transfer-Encoding: chunked\r\n"
+				+ "transfer-encoding: chunked\r\n"
 				+ "\r\n"
 				+ "{\n"
 				+ "  \"body\" : \"masked\"\n"

message/message-http/src/test/java/com/mastercard/test/flow/msg/http/HttpResTest.java

@@ -229,7 +229,7 @@ void bodyMasking() {
 	}
 
 	/**
-	 * Honouring chunked Transfer-Encoding
+	 * Honouring chunked <code>transfer-encoding</code>
 	 */
 	@Test
 	void chunked() {
@@ -242,15 +242,15 @@ void chunked() {
 				.set( "body", "content" );
 
 		assertEquals( "HTTP/1.1 200 OK\r\n"
-				+ "Transfer-Encoding: chunked\r\n"
+				+ "transfer-encoding: chunked\r\n"
 				+ "\r\n"
 				+ "{\n"
 				+ "  \"body\" : \"content\"\n"
 				+ "}",
 				msg.assertable() );
 
 		assertEquals( "HTTP/1.1 200 OK\r\n"
-				+ "Transfer-Encoding: chunked\r\n"
+				+ "transfer-encoding: chunked\r\n"
 				+ "\r\n"
 				+ "12\r\n"
 				+ "{\"body\":\"content\"}\r\n"