added context for client hooks

Signed-off-by: marcopiraccini <[email protected]>

README.md

@@ -155,12 +155,15 @@ interceptor.close();
 
 It's possible to set some simple **synchronous** functions as hooks:
 
-- `onClientRequest(req)`
-- `onClientResponse(req, res)`
-- `onClientError(req, res, error)`
-- `onServerRequest(req)`
+- `onServerRequest(req)
 - `onServerResponse(req, res)`
 - `onServerError(req, res, error)`
+- `onClientRequest(req, clientCtx)`
+- `onClientResponse(req, res, clientCtx)`
+- `onClientError(req, res, clientCtx, error)`
+
+The `clientCtx` is used to pass through hooks calls objects which cannot be set on request
+(which is then sent through `postMessage`, so it might be not serializable)
 
 #### Client hooks
 

index.js

@@ -61,7 +61,9 @@ function createThreadInterceptor (opts) {
 
       delete newOpts.dispatcher
 
-      hooks.fireOnClientRequest(newOpts)
+      // We use it as client context where hooks can add non-serializable properties
+      const clientCtx = {}
+      hooks.fireOnClientRequest(newOpts, clientCtx)
 
       if (newOpts.body?.[Symbol.asyncIterator]) {
         collectBodyAndDispatch(newOpts, handler).then(() => {
@@ -89,11 +91,11 @@ function createThreadInterceptor (opts) {
         clearTimeout(handle)
 
         if (err) {
-          hooks.fireOnClientError(newOpts, res, err)
+          hooks.fireOnClientError(newOpts, res, clientCtx, err)
           handler.onError(err)
           return
         }
-        hooks.fireOnClientResponse(newOpts, res)
+        hooks.fireOnClientResponse(newOpts, res, clientCtx)
 
         const headers = []
         for (const [key, value] of Object.entries(res.headers)) {

lib/hooks.js

@@ -6,7 +6,8 @@ const supportedHooks = [
   'onServerError',
   'onClientRequest',
   'onClientResponse',
-  'onClientError']
+  'onClientError'
+]
 
 class Hooks {
   onServerRequest = []

test/hooks.test.js

@@ -175,7 +175,7 @@ test('hooks - onClientError', async (t) => {
 
   const interceptor = createThreadInterceptor({
     domain: '.local',
-    onClientError: (_req, _rep, error) => {
+    onClientError: (_req, _rep, _ctx, error) => {
       hookCalled = error
     }
   })
@@ -198,11 +198,11 @@ test('hooks - multiple onClientErrors', async (t) => {
   t.after(() => worker.terminate())
   const hookCalled = []
 
-  const onClientError1 = (_req, _rep, error) => {
+  const onClientError1 = (_req, _rep, _ctx, error) => {
     hookCalled.push({ error1: error.message })
   }
 
-  const onClientError2 = (_req, _rep, error) => {
+  const onClientError2 = (_req, _rep, _ctx, error) => {
     hookCalled.push({ error2: error.message })
   }
 
@@ -347,3 +347,29 @@ test('hooks - request propagation between onClientRequest and onClientResponse',
   strictEqual(statusCode, 200)
   deepStrictEqual(hookCalledClient, 'propagated')
 })
+
+test('hooks - context propagation between onClientRequest and onClientResponse', async (t) => {
+  const worker = new Worker(join(__dirname, 'fixtures', 'worker1.js'))
+  t.after(() => worker.terminate())
+  let hookCalledClient
+
+  const interceptor = createThreadInterceptor({
+    domain: '.local',
+    onClientRequest: (_req, ctx) => {
+      ctx.data = 'propagated'
+    },
+    onClientResponse: (req, _res, ctx) => {
+      hookCalledClient = ctx.data
+    }
+  })
+  interceptor.route('myserver', worker)
+
+  const agent = new Agent().compose(interceptor)
+
+  const { statusCode } = await request('http://myserver.local', {
+    dispatcher: agent,
+  })
+
+  strictEqual(statusCode, 200)
+  deepStrictEqual(hookCalledClient, 'propagated')
+})