Make HTTP scheme parsing case-insensitive

Issue: SPR-10779

Author: rstoyanchev

spring-web/src/main/java/org/springframework/web/util/UriComponentsBuilder.java

@@ -60,7 +60,7 @@ public class UriComponentsBuilder {
 
 	private static final String SCHEME_PATTERN = "([^:/?#]+):";
 
-	private static final String HTTP_PATTERN = "(http|https):";
+	private static final String HTTP_PATTERN = "(?i)(http|https):";
 
 	private static final String USERINFO_PATTERN = "([^@/]*)";
 
@@ -223,7 +223,8 @@ public static UriComponentsBuilder fromHttpUrl(String httpUrl) {
 		if (m.matches()) {
 			UriComponentsBuilder builder = new UriComponentsBuilder();
 
-			builder.scheme(m.group(1));
+			String scheme = m.group(1);
+			builder.scheme((scheme != null) ? scheme.toLowerCase() : scheme);
 			builder.userInfo(m.group(4));
 			builder.host(m.group(5));
 			String port = m.group(7);

spring-web/src/test/java/org/springframework/web/util/UriComponentsBuilderTests.java

@@ -161,6 +161,14 @@ public void fromUriStringQueryParamWithReservedCharInValue() throws URISyntaxExc
 		assertEquals("1USD=?EUR", result.getQueryParams().getFirst("q"));
 	}
 
+	// SPR-10779
+
+	@Test
+	public void fromHttpUrlStringCaseInsesitiveScheme() {
+		assertEquals("http", UriComponentsBuilder.fromHttpUrl("HTTP://www.google.com").build().getScheme());
+		assertEquals("https", UriComponentsBuilder.fromHttpUrl("HTTPS://www.google.com").build().getScheme());
+	}
+
 	@Test
 	public void path() throws URISyntaxException {
 		UriComponentsBuilder builder = UriComponentsBuilder.fromPath("/foo/bar");