Fix rewrites to /index.html for non-root paths after origin 4xx/5xx

reverts a change made in e929eca
which itself was a revert in a long chain of bugs (see git blame)

Author: jotto

handler.js

@@ -161,6 +161,7 @@ module.exports.originRequest = (event, context, callback) => {
   console.log("originRequest", JSON.stringify(cloudFrontRequest));
 
   const { req, res, next, shouldPrerender } = OriginRequestInterface.create(
+    cachedOptions,
     cloudFrontRequest,
     callback
   );

lib/OriginRequestInterface.js

@@ -1,10 +1,10 @@
 const util = require("./util");
 
 module.exports = class OriginRequestInterface {
-  static create(cloudFrontRequest, callback) {
+  static create(cachedOptions, cloudFrontRequest, callback) {
     const ori = new this(cloudFrontRequest, callback);
     const { req, shouldPrerender } = ori.createReq();
-    const next = ori.createNext();
+    const next = ori.createNext(req, cachedOptions);
     const res = ori.createRes(next);
 
     return { req, res, next, shouldPrerender };
@@ -97,16 +97,22 @@ module.exports = class OriginRequestInterface {
 
     return res;
   }
-  createNext() {
+  createNext(req, cachedOptions) {
     // this flow will be called for prerender.cloud LAST_RESORT_TIMEOUT
     // aka "prerendercloud middleware SKIPPED: server error: Request timed out"
     // it will merely fall back to non-prerendered content
     return () => {
       delete this.cloudFrontRequest.headers[util.USER_AGENT_PLACEHOLDER];
 
-      if (this.originalUri === "/") {
+      if (util.shouldRewriteToIndexHtml(req, cachedOptions, this.originalUri)) {
+        console.log("OriginRequestInterface.next", {
+          rewriteToIndexHtml: true
+        });
         this.cloudFrontRequest.uri = "/index.html";
       } else {
+        console.log("OriginRequestInterface.next", {
+          rewriteToIndexHtml: false
+        });
         this.cloudFrontRequest.uri = this.originalUri;
       }
 

lib/ViewerRequestInterface.js

@@ -1,29 +1,5 @@
 const util = require("./util");
 
-// this function exists in the npm lib: prerendercloud
-// but must also exist here since we use it in our 404->/index.html
-// functionality when the file has no extension or .html extension
-const pathIsBlacklisted = (blacklistedPaths, cloudfrontUri) => {
-  const paths = blacklistedPaths;
-
-  if (paths && Array.isArray(paths)) {
-    return paths.some(path => {
-      if (path === cloudfrontUri) return true;
-
-      if (path.endsWith("*")) {
-        const starIndex = path.indexOf("*");
-        const pathSlice = path.slice(0, starIndex);
-
-        if (cloudfrontUri.startsWith(pathSlice)) return true;
-      }
-
-      return false;
-    });
-  }
-
-  return false;
-};
-
 module.exports = class ViewerRequestInterface {
   static create(cachedOptions, cloudFrontRequest, callback) {
     const vri = new this(cloudFrontRequest, callback);
@@ -109,18 +85,20 @@ module.exports = class ViewerRequestInterface {
   createNext(req, cachedOptions) {
     return () => {
       if (
-        util.isHtml(this.cloudFrontRequest.uri) &&
-        (!cachedOptions.blacklistPaths ||
-          (cachedOptions.blacklistPaths &&
-            !pathIsBlacklisted(
-              cachedOptions.blacklistPaths(req),
-              this.cloudFrontRequest.uri
-            )))
+        util.shouldRewriteToIndexHtml(
+          req,
+          cachedOptions,
+          this.cloudFrontRequest.uri
+        )
       ) {
-        console.log({ rewriteToIndexHtml: true });
+        console.log("ViewerRequestInterface.next", {
+          rewriteToIndexHtml: true
+        });
         this.cloudFrontRequest.uri = "/index.html";
       } else {
-        console.log({ rewriteToIndexHtml: false });
+        console.log("ViewerRequestInterface.next", {
+          rewriteToIndexHtml: false
+        });
       }
 
       // the URI will not include query string when not pre-rendering

lib/util.js

@@ -18,12 +18,46 @@ const parseUriField = uri => {
 
 const isHtml = require("prerendercloud").util.urlPathIsHtml;
 
+// this function exists in the npm lib: prerendercloud
+// but must also exist here since we use it in our 404->/index.html
+// functionality when the file has no extension or .html extension
+const pathIsBlacklisted = (blacklistedPaths, cloudfrontUri) => {
+  const paths = blacklistedPaths;
+
+  if (paths && Array.isArray(paths)) {
+    return paths.some(path => {
+      if (path === cloudfrontUri) return true;
+
+      if (path.endsWith("*")) {
+        const starIndex = path.indexOf("*");
+        const pathSlice = path.slice(0, starIndex);
+
+        if (cloudfrontUri.startsWith(pathSlice)) return true;
+      }
+
+      return false;
+    });
+  }
+
+  return false;
+};
+
+const shouldRewriteToIndexHtml = (req, cachedOptions, uri) => {
+  return (
+    isHtml(uri) &&
+    (!cachedOptions.blacklistPaths ||
+      (cachedOptions.blacklistPaths &&
+        !pathIsBlacklisted(cachedOptions.blacklistPaths(req), uri)))
+  );
+};
+
 module.exports = {
   USER_AGENT_PLACEHOLDER,
   toBase64,
   fromBase64,
   createUri,
   getHeader,
   parseUriField,
-  isHtml
+  isHtml,
+  shouldRewriteToIndexHtml
 };

spec/originRequestSpec.js

@@ -214,9 +214,7 @@ describe("originRequest", function() {
       withInputs("prerendercloud", "/some/path", true);
       runHandlerWithOriginRequestEvent();
 
-      // N.B. /some/path does NOT get rewritten to index.html in origin-request
-      // because it should have already been rewritten in viewer-request
-      itReturnsOriginalCloudFrontRequestWithNormalPath("/some/path");
+      itReturnsOriginalCloudFrontRequestWithNormalPath("/index.html");
     });
 
     describe("when a file with an extension", function() {