Host is no longer mandatory

It may not have ever been necessary, I think
I just forgot to pass it over the encoded URL
field like I had been for url and shouldPrerender

(because the origin request does not get the host val
from the viewer request)

Author: jotto

handler.js

@@ -37,12 +37,10 @@ const resetPrerenderCloud = () => {
   //    example use case: if your origin is http only
   // prerendercloud.set("protocol", "http");
 
-  // 3. host (mandatory)
-  //    Set this to your custom domain (something like example.com)
-  //    or if you don't have one, then the CloudFront distribution URL (something like d1pxreml448ujs.cloudfront.net)
-  //    This is what service.prerender.cloud will prerender, and if we didn't
-  //    set it, the only info we'd have access to during Lambda@Edge runtime is the host of the origin (S3)
-  //    which would require additional configuration to make it publicly accessible (and it just makes things more confusing).
+  // 3. host (optional, will infer from host header if not set here)
+  //    If having issues, try setting this to your custom domain (something like example.com)
+  //    or if you don't have one, then the CloudFront distribution URL (something like d1pxreml448ujs.cloudfront.net).
+  //    Note, setting this config option shouldn't be necessary
   //    example value: example.com or d1pxreml448ujs.cloudfront.net (don't include the protocol)
   // prerendercloud.set("host", "");
 

lib/OriginRequestInterface.js

@@ -17,21 +17,21 @@ module.exports = class OriginRequestInterface {
 
   createReq() {
     console.log("about to parse URI", this.cloudFrontRequest.uri);
-    const { uri, shouldPrerender } = util.parseUriField(
+    const { uri, shouldPrerender, host } = util.parseUriField(
       this.cloudFrontRequest.uri
     );
 
     this.originalUri = uri;
 
-    console.log("parsed URI", { uri, shouldPrerender });
+    console.log("parsed URI", { uri, shouldPrerender, host });
 
     const req = {
       connection: { encrypted: true },
       method: this.cloudFrontRequest.method,
       originalUrl: uri,
       url: uri,
       headers: {
-        host: util.getHeader(this.cloudFrontRequest, "host"),
+        host: host,
         "user-agent": util.getHeader(
           this.cloudFrontRequest,
           util.USER_AGENT_PLACEHOLDER

lib/ViewerRequestInterface.js

@@ -65,7 +65,8 @@ module.exports = class ViewerRequestInterface {
       // specifically for this Lambda lib - it's the requested path after applying the whitelistQueryParams
       this.cloudFrontRequest.uri = util.createUri(
         res.prerender.url.requestedPath,
-        true
+        true,
+        util.getHeader(this.cloudFrontRequest, "host")
       );
 
       console.log({

lib/util.js

@@ -8,8 +8,8 @@ const getHeader = (cloudFrontRequest, name) =>
 
 const toBase64 = str => Buffer.from(str).toString("base64");
 const fromBase64 = str => Buffer.from(str, "base64").toString("utf8");
-const createUri = (uri, shouldPrerender) =>
-  "/" + toBase64(JSON.stringify({ uri, shouldPrerender }));
+const createUri = (uri, shouldPrerender, host) =>
+  "/" + toBase64(JSON.stringify({ uri, shouldPrerender, host }));
 
 const parseUriField = uri => {
   // uri has leading slash

spec/originRequestSpec.js

@@ -71,7 +71,7 @@ describe("originRequest", function() {
     it("returns original CloudFront request with normal path", function() {
       expect(this.cb).toHaveBeenCalledWith(null, {
         headers: {
-          host: [{ value: "d123.cf.net", key: "Host" }],
+          host: [{ value: "origin-request-gets-s3-origin.s3.amazonaws.com", key: "Host" }],
           "user-agent": [{ value: "CloudFront", key: "User-Agent" }]
         },
         clientIp: "2001:cdba::3257:9652",
@@ -104,7 +104,7 @@ describe("originRequest", function() {
               headers: {
                 host: [
                   {
-                    value: "d123.cf.net",
+                    value: "origin-request-gets-s3-origin.s3.amazonaws.com",
                     key: "Host"
                   }
                 ],
@@ -130,7 +130,8 @@ describe("originRequest", function() {
     beforeEach(function() {
       this.event.Records[0].cf.request.uri = util.createUri(
         uri,
-        shouldPrerender
+        shouldPrerender,
+        "d123.cf.net"
       );
       this.event.Records[0].cf.request.headers[
         "prerendercloud-lambda-edge-original-user-agent"

spec/viewerRequestSpec.js

@@ -3,9 +3,10 @@ const nock = require("nock");
 
 const util = require("../lib/util");
 
-const createUriShouldPrerender = (uri, querystring) =>
-  util.createUri(uri + (querystring ? `?${querystring}` : ""), true);
-const createUriShouldNotPrerender = uri => util.createUri(uri, false);
+const createUriShouldPrerender = (uri, querystring, host = "d123.cf.net") =>
+  util.createUri(uri + (querystring ? `?${querystring}` : ""), true, host);
+const createUriShouldNotPrerender = (uri) =>
+  util.createUri(uri, false);
 
 describe("viewerRequest", function() {
   beforeEach(function() {
@@ -202,10 +203,7 @@ describe("viewerRequest", function() {
             prerendercloud.set("blacklistPaths", req => ["/signin/*"])
           );
         });
-        withUserAgentAndUri(
-          "prerendercloud random-suffix",
-          "/signin/oauth"
-        );
+        withUserAgentAndUri("prerendercloud random-suffix", "/signin/oauth");
         runHandlerWithViewerRequestEvent();
 
         itDoesNotPrerender("prerendercloud random-suffix", "/signin/oauth");

validate.js

@@ -12,15 +12,8 @@ monkeyPatchPrerenderCloud(prerendercloud, options);
 const handler = require("./handler");
 handler.resetPrerenderCloud();
 
-if (!options["host"]) {
-  throw new Error(
-    "host was not set, edit handler.js and set host to your CloudFront distribution URL or aliased domain"
-  );
-}
-
 if (!options["prerenderToken"]) {
   console.log(
     "warning, prerenderToken was not set, requests will be rate limited"
   );
 }
-