feat: implement flush() (dunglas#90)

* feat: implement flush()

* add tests

frankenphp.c

@@ -439,6 +439,15 @@ static int frankenphp_send_headers(sapi_headers_struct *sapi_headers)
 	return SAPI_HEADER_SENT_SUCCESSFULLY;
 }
 
+static void frankenphp_sapi_flush(void *server_context)
+{
+	frankenphp_server_context *ctx = (frankenphp_server_context *) server_context;
+
+	if (!ctx || ctx->current_request == 0) return;
+
+	go_sapi_flush(ctx->current_request);
+}
+
 static size_t frankenphp_read_post(char *buffer, size_t count_bytes)
 {
 	frankenphp_server_context* ctx = SG(server_context);
@@ -483,7 +492,7 @@ sapi_module_struct frankenphp_sapi_module = {
 	frankenphp_deactivate,              /* deactivate */
 
 	frankenphp_ub_write,                /* unbuffered write */
-	NULL,                   			/* flush */
+	frankenphp_sapi_flush,              /* flush */
 	NULL,                               /* get uid */
 	NULL,                               /* getenv */
 

frankenphp.go

@@ -485,6 +485,23 @@ func go_write_header(rh C.uintptr_t, status C.int) {
 	}
 }
 
+//export go_sapi_flush
+func go_sapi_flush(rh C.uintptr_t) {
+	r := cgo.Handle(rh).Value().(*http.Request)
+	fc := r.Context().Value(contextKey).(*FrankenPHPContext)
+
+	if fc.responseWriter == nil {
+		return
+	}
+
+	flusher, ok := fc.responseWriter.(http.Flusher)
+	if !ok {
+		return
+	}
+
+	flusher.Flush()
+}
+
 //export go_read_post
 func go_read_post(rh C.uintptr_t, cBuf *C.char, countBytes C.size_t) C.size_t {
 	r := cgo.Handle(rh).Value().(*http.Request)

frankenphp_test.go

@@ -438,6 +438,40 @@ func testEarlyHints(t *testing.T, opts *testOptions) {
 	}, opts)
 }
 
+type streamResponseRecorder struct {
+	*httptest.ResponseRecorder
+	writeCallback func(buf []byte)
+}
+
+func (srr *streamResponseRecorder) Write(buf []byte) (int, error) {
+	srr.writeCallback(buf)
+
+	return srr.ResponseRecorder.Write(buf)
+}
+
+func TestFlush_module(t *testing.T) { testFlush(t, &testOptions{}) }
+func TestFlush_worker(t *testing.T) {
+	testFlush(t, &testOptions{workerScript: "flush.php"})
+}
+func testFlush(t *testing.T, opts *testOptions) {
+	runTest(t, func(handler func(http.ResponseWriter, *http.Request), _ *httptest.Server, i int) {
+		var j int
+
+		req := httptest.NewRequest("GET", fmt.Sprintf("http://example.com/flush.php?i=%d", i), nil)
+		w := &streamResponseRecorder{httptest.NewRecorder(), func(buf []byte) {
+			if j == 0 {
+				assert.Equal(t, []byte("He"), buf)
+			} else {
+				assert.Equal(t, []byte(fmt.Sprintf("llo %d", i)), buf)
+			}
+
+			j++
+		}}
+		handler(w, req)
+
+		assert.Equal(t, 2, j)
+	}, opts)
+}
 func ExampleServeHTTP() {
 	if err := frankenphp.Init(); err != nil {
 		panic(err)

testdata/Caddyfile

@@ -1,7 +1,7 @@
 {
 	debug
 	frankenphp {
-		worker ./phpinfo.php
+		#worker ./phpinfo.php
 	}
 }
 

testdata/flush.php

@@ -0,0 +1,11 @@
+<?php
+
+require_once __DIR__.'/_executor.php';
+
+return function () {
+    echo 'He';
+
+    flush();
+
+    echo 'llo '.($_GET['i'] ?? '');
+};