From ee83665c5e01acbcfaaddcd552f2f6d2d3e8006c Mon Sep 17 00:00:00 2001
From: Gaubee <GaubeeBangeel@Gmail.com>
Date: Mon, 2 Dec 2024 09:08:18 +0800
Subject: [PATCH] feat: Use honoReq's bodyCache to provide a body function for
 trpc's req (#850)

Some middleware (in createContext) may need to read the body. If the raw request instance is provided directly, the body will be consumed prematurely, blocking the development of middleware.
---
 .changeset/chilly-experts-sneeze.md |  5 +++++
 packages/trpc-server/src/index.ts   | 14 +++++++++++++-
 2 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/chilly-experts-sneeze.md

diff --git a/.changeset/chilly-experts-sneeze.md b/.changeset/chilly-experts-sneeze.md
new file mode 100644
index 00000000..df53a008
--- /dev/null
+++ b/.changeset/chilly-experts-sneeze.md
@@ -0,0 +1,5 @@
+---
+'@hono/trpc-server': patch
+---
+
+Use honoReq's bodyCache to provide a body function for trpc's req
diff --git a/packages/trpc-server/src/index.ts b/packages/trpc-server/src/index.ts
index 5b8fd34d..b2b572b4 100644
--- a/packages/trpc-server/src/index.ts
+++ b/packages/trpc-server/src/index.ts
@@ -22,7 +22,10 @@ export const trpcServer = ({
   createContext,
   ...rest
 }: tRPCOptions): MiddlewareHandler => {
+  const bodyProps = new Set(['arrayBuffer', 'blob', 'formData', 'json', 'text'] as const)
+  type BodyProp = typeof bodyProps extends Set<infer T> ? T : never
   return async (c) => {
+    const canWithBody = c.req.method === 'GET' || c.req.method === 'HEAD'
     const res = fetchRequestHandler({
       ...rest,
       createContext: async (opts) => ({
@@ -31,7 +34,16 @@ export const trpcServer = ({
         env: c.env,
       }),
       endpoint,
-      req: c.req.raw,
+      req: canWithBody
+        ? c.req.raw
+        : new Proxy(c.req.raw, {
+            get(t, p, r) {
+              if (bodyProps.has(p as BodyProp)) {
+                return () => c.req[p as BodyProp]()
+              }
+              return Reflect.get(t, p, r)
+            },
+          }),
     }).then((res) => c.body(res.body, res))
     return res
   }