feat(react-18): Add streaming implementation

src/Server/config.ts

@@ -51,6 +51,7 @@ export const EDITORIAL_PATHS: any =
 export const ENABLE_CONVERSATIONS_MESSAGES_AUTO_REFRESH: any = true
 export const ENABLE_NEW_AUCTIONS_FILTER: any = false
 export const ENABLE_QUERY_BATCHING: any = false
+export const ENABLE_SSR_STREAMING: any = false
 export const ENABLE_WEB_CRAWLING: any = false
 export const ENABLE_WEB_VITALS_LOGGING: any = false
 export const GRAPHQL_CACHE_TTL: any = 1000000000

src/Server/setup_sharify.ts

@@ -46,6 +46,7 @@ sharify.data = _.extend(
     "ENABLE_CONVERSATIONS_MESSAGES_AUTO_REFRESH",
     "ENABLE_NEW_AUCTIONS_FILTER",
     "ENABLE_QUERY_BATCHING",
+    "ENABLE_SSR_STREAMING",
     "ENABLE_WEB_CRAWLING",
     "ENABLE_WEB_VITALS_LOGGING",
     "ERROR",

src/System/Boot.tsx

@@ -35,12 +35,11 @@ export interface BootProps extends React.PropsWithChildren {
 
 const { GlobalStyles } = injectGlobalStyles()
 
-export const Boot: React.FC<React.PropsWithChildren<React.PropsWithChildren<BootProps>>> = track(
-  undefined,
-  {
-    dispatch: Events.postEvent,
-  }
-)((props: BootProps) => {
+export const Boot: React.FC<React.PropsWithChildren<
+  React.PropsWithChildren<BootProps>
+>> = track(undefined, {
+  dispatch: Events.postEvent,
+})((props: BootProps) => {
   /**
    * Let our end-to-end tests know that the app is hydrated and ready to go; and
    * if in prod, initialize Sentry.
@@ -82,7 +81,6 @@ export const Boot: React.FC<React.PropsWithChildren<React.PropsWithChildren<Boot
                           >
                             <CookieConsentManager>
                               <SiftContainer />
-
                               {children}
                             </CookieConsentManager>
                           </DismissibleProvider>
@@ -100,10 +98,9 @@ export const Boot: React.FC<React.PropsWithChildren<React.PropsWithChildren<Boot
   )
 })
 
-const EnvironmentProvider: FC<React.PropsWithChildren<{ environment: Environment }>> = ({
-  children,
-  environment,
-}) => {
+const EnvironmentProvider: FC<React.PropsWithChildren<{
+  environment: Environment
+}>> = ({ children, environment }) => {
   if (process.env.NODE_ENV === "test") return <>{children}</>
 
   return (

src/System/Router/Utils/collectAssets.tsx

@@ -9,6 +9,9 @@ import RelayServerSSR, {
   SSRCache,
 } from "react-relay-network-modern-ssr/lib/server"
 import { RelayNetworkLayerResponse } from "react-relay-network-modern"
+import { ENABLE_SSR_STREAMING } from "Server/config"
+import { renderToStream } from "System/Router/Utils/renderToStream"
+import { ArtsyResponse } from "Server/middleware/artsyExpress"
 
 const STATS = "loadable-stats.json"
 
@@ -19,11 +22,13 @@ const ASSET_PATH = "/assets"
 interface CollectAssetsProps {
   ServerRouter: React.FC<React.PropsWithChildren<unknown>>
   relayEnvironment: Environment
+  res: ArtsyResponse
 }
 
 export const collectAssets = async ({
   ServerRouter,
   relayEnvironment,
+  res,
 }: CollectAssetsProps) => {
   /**
    * This is the stats file generated by Force's webpack setup, via
@@ -52,71 +57,88 @@ export const collectAssets = async ({
 
   const jsx = extractor.collectChunks(sheet.collectStyles(<ServerRouter />))
 
-  const html = renderToString(jsx)
-  const styleTags = sheet.getStyleTags()
+  let stream
+  let html
+  let styleTags
+
+  if (ENABLE_SSR_STREAMING) {
+    stream = renderToStream(jsx, sheet, res)
+  } else {
+    html = renderToString(jsx)
+    styleTags = sheet.getStyleTags()
+  }
 
   const relaySSRMiddleware = (relayEnvironment as any)
     .relaySSRMiddleware as RelayServerSSR
 
   const initialRelayData = await relaySSRMiddleware.getCache()
 
-  const initialScripts: string[] = []
-
-  const bundleScriptTags = extractor.getScriptTags()
-
-  initialScripts.push(
-    bundleScriptTags
-      .split("\n")
-      .map(script => {
-        /**
-         * In production, prefix injected script src with CDN endpoint.
-         * @see https://github.com/artsy/force/blob/main/src/lib/middleware/asset.ts#L23
-         */
-        if (getENV("CDN_URL")) {
-          const scriptTagWithCDN = script.replace(
-            /src="\/assets/g,
-            `src="${assetPublicPath}`
-          )
-          return scriptTagWithCDN
-        } else {
-          return script
-        }
-      })
-      .filter(script => {
-        return !(
+  /**
+   * Extract scripts from loadable components
+   * NOTE: When streaming is enabled we need to lazily execute script extraction
+   */
+  const extractScriptTags = () => {
+    const initialScripts: string[] = []
+
+    const bundleScriptTags = extractor.getScriptTags()
+
+    initialScripts.push(
+      bundleScriptTags
+        .split("\n")
+        .map(script => {
           /**
-           * Since these files are already embedded in our main
-           * layout file, omit them from the scripts array.
-           *
-           * TODO: Don't include these files in the main layout
-           * and instead relay on dynamically including them here.
-           * Will require some shuffling in the jade template,
-           * however.
+           * In production, prefix injected script src with CDN endpoint.
+           * @see https://github.com/artsy/force/blob/main/src/lib/middleware/asset.ts#L23
            */
-          (
-            script.includes("/assets/runtime.") ||
-            script.includes("/assets/artsy.") ||
-            script.includes("/assets/common-artsy.") ||
-            script.includes("/assets/common-react.") ||
-            script.includes("/assets/common-utility.") ||
-            script.includes("/assets/common.")
+          if (getENV("CDN_URL")) {
+            const scriptTagWithCDN = script.replace(
+              /src="\/assets/g,
+              `src="${assetPublicPath}`
+            )
+            return scriptTagWithCDN
+          } else {
+            return script
+          }
+        })
+        .filter(script => {
+          return !(
+            /**
+             * Since these files are already embedded in our main
+             * layout file, omit them from the scripts array.
+             *
+             * TODO: Don't include these files in the main layout
+             * and instead relay on dynamically including them here.
+             * Will require some shuffling in the jade template,
+             * however.
+             */
+            (
+              script.includes("/assets/runtime.") ||
+              script.includes("/assets/artsy.") ||
+              script.includes("/assets/common-artsy.") ||
+              script.includes("/assets/common-react.") ||
+              script.includes("/assets/common-utility.") ||
+              script.includes("/assets/common.")
+            )
           )
-        )
-      })
-      .join("\n")
-  )
+        })
+        .join("\n")
+    )
 
-  initialScripts.push(`
-    <script>
-      var __RELAY_BOOTSTRAP__ = ${serializeRelayData(initialRelayData)};
-    </script>
-  `)
+    initialScripts.push(`
+      <script>
+        var __RELAY_BOOTSTRAP__ = ${serializeRelayData(initialRelayData)};
+      </script>
+    `)
 
-  const scripts = initialScripts.join("\n")
+    const scripts = initialScripts.join("\n")
+
+    return scripts
+  }
 
   return {
     html,
-    scripts,
+    extractScriptTags,
+    stream,
     styleTags,
   }
 }

src/System/Router/Utils/renderToStream.tsx

@@ -0,0 +1,69 @@
+import { renderToPipeableStream } from "react-dom/server"
+import { ArtsyResponse } from "Server/middleware/artsyExpress"
+import { Transform } from "stream"
+
+const STREAM_TIMEOUT = 10000
+
+export function renderToStream(jsx, sheet, res: ArtsyResponse) {
+  let didError = false
+
+  const readerWriter = new Transform({
+    objectMode: true,
+    transform(chunk, encoding, callback) {
+      const renderedHtml =
+        chunk instanceof Uint8Array
+          ? Buffer.from(chunk).toString(encoding || "utf8")
+          : Buffer.isBuffer(chunk)
+          ? chunk.toString(encoding || "utf8")
+          : chunk
+
+      const styledCSS = sheet._emitSheetCSS()
+      const CLOSING_TAG_R = /<\/[a-z]*>/i
+
+      sheet.instance.clearTag()
+
+      // Inject CSS into HTML
+      if (/<\/head>/.test(renderedHtml)) {
+        const replacedHtml = renderedHtml.replace(
+          "</head>",
+          `${styledCSS}</head>`
+        )
+        this.push(replacedHtml)
+      } else if (CLOSING_TAG_R.test(renderedHtml)) {
+        const execResult = CLOSING_TAG_R.exec(renderedHtml) as RegExpExecArray
+        const endOfClosingTag = execResult.index + execResult[0].length
+        const before = renderedHtml.slice(0, endOfClosingTag)
+        const after = renderedHtml.slice(endOfClosingTag)
+
+        this.push(before + styledCSS + after)
+      } else {
+        this.push(styledCSS + renderedHtml)
+      }
+
+      callback()
+    },
+  })
+
+  const stream = renderToPipeableStream(jsx, {
+    onError(error) {
+      didError = true
+      console.error("error", error)
+    },
+    onShellError(error) {
+      didError = true
+      console.log("shell error", error)
+    },
+    onShellReady() {
+      res.statusCode = didError ? 500 : 200
+      res.setHeader("Content-Type", "text/html; charset=utf-8")
+      stream.pipe(readerWriter)
+    },
+  })
+
+  // Abandon and switch to client rendering if enough time passes.
+  setTimeout(() => {
+    stream.abort()
+  }, STREAM_TIMEOUT)
+
+  return readerWriter
+}

src/System/Router/__tests__/serverRouter.jest.enzyme.tsx

@@ -38,6 +38,12 @@ jest.mock("@loadable/server", () => ({
 
 jest.mock("react-tracking")
 
+jest.mock("Server/config", () => {
+  return {
+    ENABLE_SSR_STREAMING: false,
+  }
+})
+
 const defaultComponent = () => <div>hi!</div>
 
 describe("serverRouter", () => {
@@ -127,21 +133,21 @@ describe("serverRouter", () => {
     })
 
     it("bootstraps relay SSR data", async () => {
-      const { scripts } = await getWrapper()
-      expect(scripts).toContain("__RELAY_BOOTSTRAP__")
+      const { extractScriptTags } = await getWrapper()
+      expect(extractScriptTags?.()).toContain("__RELAY_BOOTSTRAP__")
     })
 
     it("does not prefix CDN_URL if not available", async () => {
       const postScripts = `<script src="/assets/foo.js"></script> <script src="/assets/bar.js"></script>`
-      const { scripts } = await getWrapper()
-      expect(scripts).toContain(postScripts)
+      const { extractScriptTags } = await getWrapper()
+      expect(extractScriptTags?.()).toContain(postScripts)
     })
 
     it("prefixes CDN_URL to script tags if available", async () => {
       process.env.CDN_URL = CDN_URL
       const postScripts = `<script src="${CDN_URL}/assets/foo.js"></script> <script src="${CDN_URL}/assets/bar.js"></script>`
-      const { scripts } = await getWrapper()
-      expect(scripts).toContain(postScripts)
+      const { extractScriptTags } = await getWrapper()
+      expect(extractScriptTags?.()).toContain(postScripts)
     })
   })