perf: removed unnecessary content pre-rendering from server render process

arctic-hen7 · arctic-hen7 · commit e1c9ad36421e · 2022-08-20T14:50:30.000+10:00
For subsequent loads, the browser just needs the state to render the
page itself, and the Wasm is already instantiated, so there's no reason
to generate the content on the server as well, which slows page loads
down and increases the amount needing to be transferred over the
network. The gains from this commit are minimal, but present.
diff --git a/packages/perseus-actix-web/src/initial_load.rs b/packages/perseus-actix-web/src/initial_load.rs
@@ -91,6 +91,7 @@ pub async fn initial_load<M: MutableStore, T: TranslationsManager>(
                     translations_manager: translations_manager.get_ref(),
                 },
                 template,
+                true, // This is an initial load, so we do want the content rendered/fetched
             )
             .await;
             let page_data = match page_data {
diff --git a/packages/perseus-actix-web/src/page_data.rs b/packages/perseus-actix-web/src/page_data.rs
@@ -4,6 +4,7 @@ use fmterr::fmt_err;
 use perseus::{
     errors::err_to_status_code,
     i18n::TranslationsManager,
+    internal::PageDataPartial,
     server::{get_page_for_template, GetPageProps, ServerOptions},
     stores::{ImmutableStore, MutableStore},
 };
@@ -68,18 +69,23 @@ pub async fn page_data<M: MutableStore, T: TranslationsManager>(
                 translations_manager: translations_manager.get_ref(),
             },
             template,
+            false, // For subsequent loads, we don't want to render content (the client can do it)
         )
         .await;
         match page_data {
             Ok(page_data) => {
+                let partial_page_data = PageDataPartial {
+                    state: page_data.state,
+                    head: page_data.head,
+                };
                 let mut http_res = HttpResponse::Ok();
                 http_res.content_type("text/html");
                 // Generate and add HTTP headers
-                for (key, val) in template.get_headers(page_data.state.clone()) {
+                for (key, val) in template.get_headers(partial_page_data.state.clone()) {
                     http_res.insert_header((key.unwrap(), val));
                 }
 
-                http_res.body(serde_json::to_string(&page_data).unwrap())
+                http_res.body(serde_json::to_string(&partial_page_data).unwrap())
             }
             // We parse the error to return an appropriate status code
             Err(err) => {
diff --git a/packages/perseus-axum/src/initial_load.rs b/packages/perseus-axum/src/initial_load.rs
@@ -86,6 +86,7 @@ pub async fn initial_load_handler<M: MutableStore, T: TranslationsManager>(
                     translations_manager: &translations_manager,
                 },
                 template,
+                true,
             )
             .await;
             let page_data = match page_data {
diff --git a/packages/perseus-axum/src/page_data.rs b/packages/perseus-axum/src/page_data.rs
@@ -7,6 +7,7 @@ use fmterr::fmt_err;
 use perseus::{
     errors::err_to_status_code,
     i18n::TranslationsManager,
+    internal::PageDataPartial,
     server::{get_page_for_template, GetPageProps, ServerOptions},
     stores::{ImmutableStore, MutableStore},
     Request,
@@ -85,18 +86,23 @@ pub async fn page_handler<M: MutableStore, T: TranslationsManager>(
                 translations_manager: &translations_manager,
             },
             template,
+            false,
         )
         .await;
         match page_data {
             Ok(page_data) => {
+                let partial_page_data = PageDataPartial {
+                    state: page_data.state,
+                    head: page_data.head,
+                };
                 // http_res.content_type("text/html");
                 // Generate and add HTTP headers
                 let mut header_map = HeaderMap::new();
-                for (key, val) in template.get_headers(page_data.state.clone()) {
+                for (key, val) in template.get_headers(partial_page_data.state.clone()) {
                     header_map.insert(key.unwrap(), val);
                 }
 
-                let page_data_str = serde_json::to_string(&page_data).unwrap();
+                let page_data_str = serde_json::to_string(&partial_page_data).unwrap();
 
                 (StatusCode::OK, header_map, page_data_str)
             }
diff --git a/packages/perseus-warp/src/initial_load.rs b/packages/perseus-warp/src/initial_load.rs
@@ -77,6 +77,7 @@ pub async fn initial_load_handler<M: MutableStore, T: TranslationsManager>(
                     translations_manager: &translations_manager,
                 },
                 template,
+                true,
             )
             .await;
             let page_data = match page_data {
diff --git a/packages/perseus-warp/src/page_data.rs b/packages/perseus-warp/src/page_data.rs
@@ -2,6 +2,7 @@ use fmterr::fmt_err;
 use perseus::{
     errors::err_to_status_code,
     i18n::TranslationsManager,
+    internal::PageDataPartial,
     server::{get_page_for_template, GetPageProps, ServerOptions},
     stores::{ImmutableStore, MutableStore},
 };
@@ -65,18 +66,23 @@ pub async fn page_handler<M: MutableStore, T: TranslationsManager>(
                 translations_manager: &translations_manager,
             },
             template,
+            false,
         )
         .await;
         match page_data {
             Ok(page_data) => {
+                let partial_page_data = PageDataPartial {
+                    state: page_data.state,
+                    head: page_data.head,
+                };
                 let mut http_res = Response::builder().status(200);
                 // http_res.content_type("text/html");
                 // Generate and add HTTP headers
-                for (key, val) in template.get_headers(page_data.state.clone()) {
+                for (key, val) in template.get_headers(partial_page_data.state.clone()) {
                     http_res = http_res.header(key.unwrap(), val);
                 }
 
-                let page_data_str = serde_json::to_string(&page_data).unwrap();
+                let page_data_str = serde_json::to_string(&partial_page_data).unwrap();
                 http_res.body(page_data_str).unwrap()
             }
             // We parse the error to return an appropriate status code
diff --git a/packages/perseus/src/export.rs b/packages/perseus/src/export.rs
@@ -1,5 +1,6 @@
 use crate::errors::*;
 use crate::i18n::{Locales, TranslationsManager};
+use crate::page_data::PageDataPartial;
 use crate::server::{get_render_cfg, HtmlShell};
 use crate::stores::ImmutableStore;
 use crate::template::TemplateMap;
@@ -216,7 +217,11 @@ pub async fn export_path(
 
             // Serialize the page data to JSON and write it as a partial (fetched by the app
             // shell for subsequent loads)
-            let partial = serde_json::to_string(&page_data).unwrap();
+            let partial_page_data = PageDataPartial {
+                state: page_data.state,
+                head: page_data.head,
+            };
+            let partial = serde_json::to_string(&partial_page_data).unwrap();
             immutable_store
                 .write(
                     &format!("exported/.perseus/page/{}/{}.json", locale, &path),
@@ -246,7 +251,11 @@ pub async fn export_path(
 
         // Serialize the page data to JSON and write it as a partial (fetched by the app
         // shell for subsequent loads)
-        let partial = serde_json::to_string(&page_data).unwrap();
+        let partial_page_data = PageDataPartial {
+            state: page_data.state,
+            head: page_data.head,
+        };
+        let partial = serde_json::to_string(&partial_page_data).unwrap();
         immutable_store
             .write(
                 &format!("exported/.perseus/page/{}/{}.json", locales.default, &path),
diff --git a/packages/perseus/src/lib.rs b/packages/perseus/src/lib.rs
@@ -101,6 +101,7 @@ pub use client::{run_client, ClientReturn};
 /// TODO
 #[cfg(not(target_arch = "wasm32"))]
 pub mod internal {
+    pub use crate::page_data::*;
     pub use crate::{build::*, export::*};
 }
 /// Internal utilities for logging. These are just re-exports so that users
diff --git a/packages/perseus/src/page_data.rs b/packages/perseus/src/page_data.rs
@@ -12,3 +12,18 @@ pub struct PageData {
     /// The string to interpolate into the document's `<head>`.
     pub head: String,
 }
+
+/// A version of [`PageData`] that doesn't contain the HTML content of the page.
+/// This is designed for being to sent to the client as part of a subsequent
+/// load, since the browser can render the HTML content of a page on its own.
+///
+/// Note that this still contains the `<head>`.
+#[derive(Serialize, Deserialize, Debug, Clone)]
+pub struct PageDataPartial {
+    /// The state for hydration. This is kept as a string for ease of typing.
+    /// Some pages may not need state or generate it in another way, so this
+    /// might be `None`.
+    pub state: Option<String>,
+    /// The string to interpolate into the document's `<head>`.
+    pub head: String,
+}
diff --git a/packages/perseus/src/router/get_subsequent_view.rs b/packages/perseus/src/router/get_subsequent_view.rs
@@ -1,7 +1,7 @@
 use crate::error_pages::ErrorPages;
 use crate::errors::*;
 use crate::i18n::ClientTranslationsManager;
-use crate::page_data::PageData;
+use crate::page_data::PageDataPartial;
 use crate::router::{get_global_state, RouteVerdict, RouterLoadState, RouterState};
 use crate::template::{PageProps, Template, TemplateNodeType};
 use crate::utils::checkpoint;
@@ -97,7 +97,7 @@ pub(crate) async fn get_subsequent_view(
         Ok(page_data_str_opt) => match page_data_str_opt {
             Some(page_data_str) => {
                 // All good, deserialize the page data
-                let page_data = serde_json::from_str::<PageData>(&page_data_str);
+                let page_data = serde_json::from_str::<PageDataPartial>(&page_data_str);
                 match page_data {
                     Ok(page_data) => {
                         // Interpolate the metadata directly into the document's `<head>`
diff --git a/packages/perseus/src/server/render.rs b/packages/perseus/src/server/render.rs

Original file line number	Diff line number	Diff line change
`@@ -91,6 +91,7 @@ pub async fn initial_load<M: MutableStore, T: TranslationsManager>(`
`91`	`91`	`translations_manager: translations_manager.get_ref(),`
`92`	`92`	`},`
`93`	`93`	`template,`
	`94`	`+ true, // This is an initial load, so we do want the content rendered/fetched`
`94`	`95`	`)`
`95`	`96`	`.await;`
`96`	`97`	`let page_data = match page_data {`
Original file line number	Diff line number	Diff line change
`@@ -86,6 +86,7 @@ pub async fn initial_load_handler<M: MutableStore, T: TranslationsManager>(`
`86`	`86`	`translations_manager: &translations_manager,`
`87`	`87`	`},`
`88`	`88`	`template,`
	`89`	`+ true,`
`89`	`90`	`)`
`90`	`91`	`.await;`
`91`	`92`	`let page_data = match page_data {`
Original file line number	Diff line number	Diff line change
`@@ -77,6 +77,7 @@ pub async fn initial_load_handler<M: MutableStore, T: TranslationsManager>(`
`77`	`77`	`translations_manager: &translations_manager,`
`78`	`78`	`},`
`79`	`79`	`template,`
	`80`	`+ true,`
`80`	`81`	`)`
`81`	`82`	`.await;`
`82`	`83`	`let page_data = match page_data {`
Original file line number	Diff line number	Diff line change
`@@ -101,6 +101,7 @@ pub use client::{run_client, ClientReturn};`
`101`	`101`	`/// TODO`
`102`	`102`	`#[cfg(not(target_arch = "wasm32"))]`
`103`	`103`	`pub mod internal {`
	`104`	`+ pub use crate::page_data::*;`
`104`	`105`	`pub use crate::{build::, export::};`
`105`	`106`	`}`
`106`	`107`	`/// Internal utilities for logging. These are just re-exports so that users`