Add Better Path Handling (netty#12533)

Motivation:

Paths, especially those of the form "//path/to/resource" are handled as "/path/to/resource" by most browsers and servers, but Netty fails on these, parsing them as having an authority.

Modification:

Directly forward the uri when it's a path instead of trying to parse it.

Also clean up isOriginForm/isAsteriskForm as their logic seems to be incorrect (for example, URI#getSchemeSpecificPart() never returns null so they both return false trivially).

Result:

Netty forwards uris unchanged when they look to be in origin or asterisk form.

codec-http2/src/main/java/io/netty/handler/codec/http2/HttpConversionUtil.java

@@ -49,8 +49,6 @@
 import static io.netty.handler.codec.http.HttpResponseStatus.parseLine;
 import static io.netty.handler.codec.http.HttpScheme.HTTP;
 import static io.netty.handler.codec.http.HttpScheme.HTTPS;
-import static io.netty.handler.codec.http.HttpUtil.isAsteriskForm;
-import static io.netty.handler.codec.http.HttpUtil.isOriginForm;
 import static io.netty.handler.codec.http2.Http2Error.PROTOCOL_ERROR;
 import static io.netty.handler.codec.http2.Http2Exception.connectionError;
 import static io.netty.handler.codec.http2.Http2Exception.streamError;
@@ -435,16 +433,20 @@ public static Http2Headers toHttp2Headers(HttpMessage in, boolean validateHeader
         final Http2Headers out = new DefaultHttp2Headers(validateHeaders, inHeaders.size());
         if (in instanceof HttpRequest) {
             HttpRequest request = (HttpRequest) in;
-            URI requestTargetUri = URI.create(request.uri());
-            out.path(toHttp2Path(requestTargetUri));
-            out.method(request.method().asciiName());
-            setHttp2Scheme(inHeaders, requestTargetUri, out);
-
-            if (!isOriginForm(requestTargetUri) && !isAsteriskForm(requestTargetUri)) {
-                // Attempt to take from HOST header before taking from the request-line
-                String host = inHeaders.getAsString(HttpHeaderNames.HOST);
-                setHttp2Authority(host == null || host.isEmpty() ? requestTargetUri.getAuthority() : host, out);
+            String host = inHeaders.getAsString(HttpHeaderNames.HOST);
+            if (request.uri().startsWith("/") || "*".equals(request.uri())) {
+                // Origin or asterisk form
+                out.path(new AsciiString(request.uri()));
+                setHttp2Scheme(inHeaders, out);
+            } else {
+                URI requestTargetUri = URI.create(request.uri());
+                out.path(toHttp2Path(requestTargetUri));
+                // Take from the request-line if HOST header was empty
+                host = isNullOrEmpty(host) ? requestTargetUri.getAuthority() : host;
+                setHttp2Scheme(inHeaders, requestTargetUri, out);
             }
+            setHttp2Authority(host, out);
+            out.method(request.method().asciiName());
         } else if (in instanceof HttpResponse) {
             HttpResponse response = (HttpResponse) in;
             out.status(response.status().codeAsText());
@@ -602,9 +604,13 @@ static void setHttp2Authority(String authority, Http2Headers out) {
         }
     }
 
+    private static void setHttp2Scheme(HttpHeaders in, Http2Headers out) {
+        setHttp2Scheme(in, URI.create(""), out);
+    }
+
     private static void setHttp2Scheme(HttpHeaders in, URI uri, Http2Headers out) {
         String value = uri.getScheme();
-        if (value != null) {
+        if (!isNullOrEmpty(value)) {
             out.scheme(new AsciiString(value));
             return;
         }

codec-http2/src/test/java/io/netty/handler/codec/http2/HttpConversionUtilTest.java

@@ -16,6 +16,7 @@
 package io.netty.handler.codec.http2;
 
 import io.netty.handler.codec.http.DefaultHttpHeaders;
+import io.netty.handler.codec.http.DefaultHttpRequest;
 import io.netty.handler.codec.http.HttpHeaders;
 import io.netty.handler.codec.http.HttpMethod;
 import io.netty.handler.codec.http.HttpRequest;
@@ -174,6 +175,39 @@ public void stripConnectionNomineesWithCsv() {
         assertSame("world", out.get("hello"));
     }
 
+    @Test
+    public void handlesRequest() throws Exception {
+        boolean validateHeaders = true;
+        HttpRequest msg = new DefaultHttpRequest(
+            HttpVersion.HTTP_1_1, HttpMethod.GET, "http://example.com/path/to/something", validateHeaders);
+        HttpHeaders inHeaders = msg.headers();
+        inHeaders.add(CONNECTION, "foo,  bar");
+        inHeaders.add("hello", "world");
+        Http2Headers out = HttpConversionUtil.toHttp2Headers(msg, validateHeaders);
+        assertEquals(new AsciiString("/path/to/something"), out.path());
+        assertEquals(new AsciiString("http"), out.scheme());
+        assertEquals(new AsciiString("example.com"), out.authority());
+        assertEquals(HttpMethod.GET.asciiName(), out.method());
+        assertEquals("world", out.get("hello"));
+    }
+
+    @Test
+    public void handlesRequestWithDoubleSlashPath() throws Exception {
+        boolean validateHeaders = true;
+        HttpRequest msg = new DefaultHttpRequest(
+            HttpVersion.HTTP_1_1, HttpMethod.GET, "//path/to/something", validateHeaders);
+        HttpHeaders inHeaders = msg.headers();
+        inHeaders.add(CONNECTION, "foo,  bar");
+        inHeaders.add(HOST, "example.com");
+        inHeaders.add(HttpConversionUtil.ExtensionHeaderNames.SCHEME.text(), "http");
+        inHeaders.add("hello", "world");
+        Http2Headers out = HttpConversionUtil.toHttp2Headers(msg, validateHeaders);
+        assertEquals(new AsciiString("//path/to/something"), out.path());
+        assertEquals(new AsciiString("http"), out.scheme());
+        assertEquals(new AsciiString("example.com"), out.authority());
+        assertEquals(HttpMethod.GET.asciiName(), out.method());
+    }
+
     @Test
     public void addHttp2ToHttpHeadersCombinesCookies() throws Http2Exception {
         Http2Headers inHeaders = new DefaultHttp2Headers();