feat: add compatibility for env BODY_SIZE_LIMIT

Author: TheOrdinaryWow

README.md

@@ -60,19 +60,19 @@ export default {
 
 ### out
 
-The directory to build the server to. It defaults to `build` — i.e. `bun run start` would start the server locally after it has been created.
+The directory to build the server to. Default: `build` — i.e. `bun run start` would start the server locally after it has been created.
 
 ### precompress
 
-Enables precompressing using gzip and brotli for assets and prerendered pages. It defaults to `false`.
+Enables precompressing using gzip and brotli for assets and prerendered pages. Default: `false`.
 
 #### brotli
 
-Enable brotli precompressing. It defaults to `false`.
+Enable brotli precompressing. Default: `false`.
 
 #### gzip
 
-Enable gzip precompressing. It defaults to `false`.
+Enable gzip precompressing. Default: `false`.
 
 ### development
 
@@ -90,6 +90,18 @@ Specify the port and host to listen on.
 
 Default: `0.0.0.0`, `3000`
 
+### `BODY_SIZE_LIMIT`
+
+The maximum request body size to accept in bytes including while streaming.
+
+Accepted inputs:
+
+- Raw number in bytes, e.g. `1048576`.
+- String with a unit suffix (`K`, `M`, `G`), e.g. `1M`.
+- Literal string `"Infinity"` or number `0` to disable body size limit.
+
+Default: `512K`
+
 ### `ORIGIN`, `PROTOCOL_HEADER` and `HOST_HEADER`
 
 HTTP doesn't give SvelteKit a reliable way to know the URL that is currently being requested. The simplest way to tell SvelteKit where the app is being served is to set the `ORIGIN` environment variable.

src/server/env.ts

@@ -8,7 +8,13 @@ const env = createEnv({
     // Server port number
     PORT: z.coerce.number().int().gte(1).lte(65535).default(3000),
     // Maximum request body size (optional)
-    BODY_SIZE_LIMIT: z.coerce.number().int().gt(0).optional(),
+    BODY_SIZE_LIMIT: z
+      .union([
+        z.coerce.number().int().gte(0),
+        z.string().refine((val) => /^(\d+)(K|M|G)?$/i.test(val), {}),
+        z.literal("Infinity").transform(() => Number.POSITIVE_INFINITY),
+      ])
+      .default("512K"),
     // Application origin URL
     ORIGIN: z.string().url().default("http://localhost:3000"),
     // Header for forwarded protocol

src/server/index.ts

@@ -2,7 +2,7 @@ import env from "./env";
 import { buildKitServer } from "./kit-server";
 import { buildRoutes } from "./routes";
 import { handleSSRRequest } from "./routes/ssr";
-import { getManifestFile } from "./utils";
+import { getManifestFile, parseEnvBytes } from "./utils";
 
 async function getBunServeConfig(): Promise<Parameters<typeof Bun.serve>[0]> {
   const { manifest } = await getManifestFile();
@@ -11,7 +11,7 @@ async function getBunServeConfig(): Promise<Parameters<typeof Bun.serve>[0]> {
   return {
     port: env.PORT,
     hostname: env.HOST,
-    maxRequestBodySize: env.BODY_SIZE_LIMIT,
+    maxRequestBodySize: parseEnvBytes(env.BODY_SIZE_LIMIT),
     development: env.DEV_MODE,
     routes: await buildRoutes(),
     async fetch(req, srv) {

src/server/utils.ts

@@ -40,3 +40,24 @@ export function get_origin(headers: Headers): string {
 
   return `${protocol}://${host}`;
 }
+
+export function parseEnvBytes(input: string | number): number {
+  if (typeof input === "number") return input === 0 ? Number.POSITIVE_INFINITY : input;
+
+  // biome-ignore lint/style/noNonNullAssertion: guarded by `zod`
+  const match = input.match(/^(\d+)(?:(K|M|G))?$/i)!;
+
+  const size = Number.parseInt(match[1] || "0", 10);
+  const unit = match[2]?.toUpperCase() || "";
+
+  switch (unit) {
+    case "K":
+      return size * 1024;
+    case "M":
+      return size * 1024 * 1024;
+    case "G":
+      return size * 1024 * 1024 * 1024;
+    default:
+      return size;
+  }
+}