Bug 1718673 - Allow loading text/event-stream in-browser as plain-text, r=smaug,necko-reviewers,kershaw

This patch also updates some documentation which was telling folks supporting new content types to update dead code.

Differential Revision: https://phabricator.services.mozilla.com/D211797

dom/base/nsContentUtils.cpp

@@ -4632,8 +4632,8 @@ bool nsContentUtils::IsChildOfSameType(Document* aDoc) {
 }
 
 bool nsContentUtils::IsPlainTextType(const nsACString& aContentType) {
-  // NOTE: if you add a type here, add it to the CONTENTDLF_CATEGORIES
-  // define in nsContentDLF.h as well.
+  // NOTE: if you add a type here, add it to the content_types array in
+  // layout/build/components.conf as well.
   return aContentType.EqualsLiteral(TEXT_PLAIN) ||
          aContentType.EqualsLiteral(TEXT_CSS) ||
          aContentType.EqualsLiteral(TEXT_CACHE_MANIFEST) ||
@@ -4644,7 +4644,8 @@ bool nsContentUtils::IsPlainTextType(const nsACString& aContentType) {
          aContentType.EqualsLiteral(APPLICATION_ECMASCRIPT) ||
          aContentType.EqualsLiteral(TEXT_JAVASCRIPT) ||
          aContentType.EqualsLiteral(APPLICATION_JSON) ||
-         aContentType.EqualsLiteral(TEXT_JSON);
+         aContentType.EqualsLiteral(TEXT_JSON) ||
+         aContentType.EqualsLiteral(TEXT_EVENT_STREAM);
 }
 
 bool nsContentUtils::IsUtf8OnlyPlainTextType(const nsACString& aContentType) {

layout/build/components.conf

@@ -28,6 +28,7 @@ content_types = [
     'text/cache-manifest',
     'text/css',
     'text/ecmascript',
+    'text/event-stream',
     'text/html',
     'text/javascript',
     'text/json',

layout/build/nsContentDLF.h

@@ -55,38 +55,4 @@ class nsContentDLF final : public nsIDocumentLoaderFactory {
 
 nsresult NS_NewContentDocumentLoaderFactory(nsIDocumentLoaderFactory** aResult);
 
-// clang-format off
-#ifdef MOZ_WEBM
-#define CONTENTDLF_WEBM_CATEGORIES \
-    { "Gecko-Content-Viewers", VIDEO_WEBM, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", AUDIO_WEBM, "@mozilla.org/content/document-loader-factory;1" },
-#else
-#define CONTENTDLF_WEBM_CATEGORIES
-#endif
-
-#define CONTENTDLF_CATEGORIES \
-    { "Gecko-Content-Viewers", TEXT_HTML, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", TEXT_PLAIN, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", TEXT_CACHE_MANIFEST, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", TEXT_CSS, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", TEXT_JAVASCRIPT, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", TEXT_ECMASCRIPT, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", APPLICATION_JAVASCRIPT, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", APPLICATION_ECMASCRIPT, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", APPLICATION_XJAVASCRIPT, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", APPLICATION_JSON, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", TEXT_JSON, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", APPLICATION_XHTML_XML, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", TEXT_XML, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", APPLICATION_XML, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", APPLICATION_RDF_XML, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", TEXT_RDF, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", VIEWSOURCE_CONTENT_TYPE, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", IMAGE_SVG_XML, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", APPLICATION_MATHML_XML, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", TEXT_VTT, "@mozilla.org/content/document-loader-factory;1" }, \
-    { "Gecko-Content-Viewers", APPLICATION_WAPXHTML_XML, "@mozilla.org/content/document-loader-factory;1" }, \
-    CONTENTDLF_WEBM_CATEGORIES
-// clang-format on
-
 #endif

netwerk/test/browser/browser.toml

@@ -160,6 +160,9 @@ skip-if = ["os == 'win'"] # Bug 1775761
 
 ["browser_cookie_sync_across_tabs.js"]
 
+["browser_display_plaintext_types.js"]
+support-files = ["res_hello_h1.sjs"]
+
 ["browser_dns_prefetch_link_header.js"]
 
 ["browser_fetch_lnk.js"]

netwerk/test/browser/browser_display_plaintext_types.js

@@ -0,0 +1,64 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const BASE_URI =
+  "http://mochi.test:8888/browser/netwerk/test/browser/res_hello_h1.sjs?type=";
+
+async function expectOutcome(aContentType, aBehavior) {
+  info(`Expecting ${aContentType} to be loaded as ${aBehavior}`);
+  const url = BASE_URI + aContentType;
+
+  await BrowserTestUtils.withNewTab(url, async browser => {
+    await SpecialPowers.spawn(browser, [url, aBehavior], (url, aBehavior) => {
+      is(content.location.href, url, "expected url was loaded");
+      switch (aBehavior) {
+        case "html":
+          is(
+            content.document.querySelector("h1").textContent,
+            "hello",
+            "parsed as HTML, so document should contain an <h1> element"
+          );
+          break;
+        case "text":
+          is(
+            content.document.body.textContent,
+            "<h1>hello</h1>",
+            "parsed as text, so document should contain bare text"
+          );
+          break;
+        case "jsonviewer":
+          ok(
+            content.wrappedJSObject.JSONView,
+            "page has loaded the DevTools JSONViewer"
+          );
+          break;
+        default:
+          ok(false, "unexpected behavior");
+          break;
+      }
+    });
+  });
+}
+
+add_task(async function test_display_plaintext_type() {
+  // Make sure that if the data is HTML it loads as HTML.
+  await expectOutcome("text/html", "html");
+
+  // For other text-like types, make sure we load as plain text.
+  await expectOutcome("text/plain", "text");
+
+  await expectOutcome("application/ecmascript", "text");
+  await expectOutcome("application/javascript", "text");
+  await expectOutcome("application/x-javascript", "text");
+  await expectOutcome("text/cache-manifest", "text");
+  await expectOutcome("text/css", "text");
+  await expectOutcome("text/ecmascript", "text");
+  await expectOutcome("text/event-stream", "text");
+  await expectOutcome("text/javascript", "text");
+
+  await expectOutcome("application/json", "jsonviewer");
+  // NOTE: text/json does not load JSON viewer?
+  await expectOutcome("text/json", "text");
+});

netwerk/test/browser/res_hello_h1.sjs

@@ -0,0 +1,14 @@
+"use strict";
+
+function handleRequest(request, response) {
+  const query = new URLSearchParams(request.queryString);
+
+  // If the
+  let type = "text/html";
+  if (query.has("type")) {
+    type = query.get("type");
+  }
+  response.setHeader("Content-Type", type, false);
+
+  response.write(`<h1>hello</h1>`);
+}

uriloader/docs/uriloader.rst

@@ -43,4 +43,4 @@ flags passed to the loader service):
 
 For the most part the process ends at step 1 because nsDocShell passes a ``nsDSURIContentListener``
 for the ``nsIURIContentListener`` consulted first and it accepts most of the
-`web content types <https://searchfox.org/mozilla-central/search?q=CONTENTDLF_CATEGORIES&redirect=false>`_.
+`web content types <https://searchfox.org/mozilla-central/source/layout/build/components.conf>`_.