add function to send 103 http response code (VKCOM#560)

New function `send_http_103_early_hints($headers)` sends HTTP 103 response with passed headers immediately without buffering

builtin-functions/_functions.txt

@@ -135,6 +135,7 @@ function ob_get_level () ::: int;
 
 function header ($str ::: string, $replace ::: bool = true, $http_response_code ::: int = 0) ::: void;
 function headers_list () ::: string[];
+function send_http_103_early_hints($headers ::: string[]) ::: void;
 function setcookie ($name ::: string, $value ::: string, $expire ::: int = 0, $path ::: string = '', $domain ::: string = '', $secure ::: bool = false, $http_only ::: bool = false) ::: void;
 function setrawcookie ($name ::: string, $value ::: string, $expire ::: int = 0, $path ::: string = '', $domain ::: string = '', $secure ::: bool = false, $http_only ::: bool = false) ::: void;
 function register_shutdown_function (callable():void $function) ::: void;

runtime/interface.cpp

@@ -332,6 +332,14 @@ array<string> f$headers_list() {
   return result;
 }
 
+void f$send_http_103_early_hints(const array<string> & headers) {
+  string header("HTTP/1.1 103 Early Hints\r\n");
+  for (const auto & h : headers) {
+    header.append(h.get_value().c_str()).append("\r\n");
+  }
+  http_send_immediate_response(header.c_str(), header.size(), "\r\n", 2);
+}
+
 void f$setrawcookie(const string &name, const string &value, int64_t expire, const string &path, const string &domain, bool secure, bool http_only) {
   string date = f$gmdate(HTTP_DATE, expire);
 

runtime/interface.h

@@ -44,6 +44,8 @@ void f$header(const string &str, bool replace = true, int64_t http_response_code
 
 array<string> f$headers_list();
 
+void f$send_http_103_early_hints(const array<string> & headers);
+
 void f$setcookie(const string &name, const string &value, int64_t expire = 0, const string &path = string(), const string &domain = string(), bool secure = false, bool http_only = false);
 
 void f$setrawcookie(const string &name, const string &value, int64_t expire = 0, const string &path = string(), const string &domain = string(), bool secure = false, bool http_only = false);

server/php-queries.cpp

@@ -14,6 +14,9 @@
 #include "common/precise-time.h"
 #include "common/wrappers/overloaded.h"
 
+#include "net/net-buffers.h"
+#include "net/net-connections.h"
+
 #include "runtime/allocator.h"
 #include "runtime/job-workers/processing-jobs.h"
 #include "runtime/rpc.h"
@@ -24,6 +27,7 @@
 #include "server/php-init-scripts.h"
 #include "server/php-queries-stats.h"
 #include "server/php-runner.h"
+#include "server/php-worker.h"
 
 #define MAX_NET_ERROR_LEN 128
 
@@ -953,6 +957,17 @@ void db_run_query(int host_num, const char *request, int request_len, int timeou
   }
 }
 
+void http_send_immediate_response(const char *headers, int headers_len, const char *body, int body_len) {
+  php_assert(active_worker != nullptr);
+  if (active_worker->mode == http_worker) {
+    write_out(&active_worker->conn->Out, headers, headers_len);
+    write_out(&active_worker->conn->Out, body, body_len);
+    flush_connection_output(active_worker->conn);
+  } else {
+    php_warning("Early hints available only from HTTP worker");
+  }
+}
+
 slot_id_t rpc_send_query(int host_num, char *request, int request_size, int timeout_ms) {
   net_query_t *query = create_net_query();
   if (query == nullptr) {

server/php-queries.h

@@ -319,6 +319,7 @@ void job_set_result(int exit_code);
 
 void script_error();
 void finish_script(int exit_code);
+void http_send_immediate_response(const char *headers, int headers_len, const char *body, int body_len);
 int rpc_connect_to(const char *host_name, int port);
 slot_id_t rpc_send_query(int host_num, char *request, int request_len, int timeout_ms);
 void wait_net_events(int timeout_ms);

tests/python/lib/http_client.py

@@ -4,6 +4,23 @@
 
 from .colors import blue
 
+class RawResponse:
+    def __init__(self, raw_bytes):
+        self.raw_bytes = raw_bytes
+        head, _, body = raw_bytes.partition(b"\r\n\r\n")
+
+        first_line, _, headers_data = head.partition(b"\r\n")
+        self.method, _, status = first_line.partition(b' ')
+        status_code, _, status_line = status.partition(b' ')
+        self.status_code = int(status_code)
+        self.reason = status_line
+        self.headers = {}
+        self.content = body
+
+        for i in headers_data.splitlines():
+            k, v = i.split(b': ')
+            self.headers[k.decode()] = v.decode()
+
 
 def send_http_request(port, uri='/', method='GET', **kwargs):
     session = requests.session()
@@ -45,21 +62,4 @@ def send_http_request_raw(port, request):
     print(*response_bytes.splitlines(True), sep="\n")
     print("=============================")
 
-    class _RawResponse:
-        def __init__(self, raw_bytes):
-            self.raw_bytes = raw_bytes
-            head, _, body = raw_bytes.partition(b"\r\n\r\n")
-
-            first_line, _, headers_data = head.partition(b"\r\n")
-            self.method, _, status = first_line.partition(b' ')
-            status_code, _, status_line = status.partition(b' ')
-            self.status_code = int(status_code)
-            self.reason = status_line
-            self.headers = {}
-            self.content = body
-
-            for i in headers_data.splitlines():
-                k, v = i.split(b': ')
-                self.headers[k.decode()] = v.decode()
-
-    return _RawResponse(response_bytes)
+    return RawResponse(response_bytes)

tests/python/tests/http_server/php/index.php

@@ -49,5 +49,9 @@ class A {
 } else if ($_SERVER["PHP_SELF"] === "/pid") {
     echo "pid=" . posix_getpid();
 } else {
-  echo "Hello world!";
+    if ($_GET["hints"] === "yes") {
+        send_http_103_early_hints(["Content-Type: text/plain or application/json", "Link: </script.js>; rel=preload; as=script"]);
+        sleep(2);
+    }
+    echo "Hello world!";
 }

tests/python/tests/http_server/test_request.py

@@ -1,6 +1,8 @@
 import urllib
+import socket
 
 from python.lib.testcase import KphpServerAutoTestCase
+from python.lib.http_client import RawResponse
 
 
 class TestRequest(KphpServerAutoTestCase):
@@ -9,6 +11,36 @@ def test_send_simple_request_path(self):
         self.assertEqual(response.status_code, 200)
         self.assertEqual(response.content, b"Hello world!")
 
+    def test_send_request_with_early_hints(self):
+        def print_log(header, body):
+            print(header)
+            print("=============================")
+            print(*body.splitlines(True), sep="\n")
+            print("=============================")
+        msg = b"GET /?hints=yes HTTP/1.1\n\n"
+        print_log("\nSending Raw HTTP request", msg)
+        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
+            s.connect(('127.0.0.1', self.kphp_server.http_port))
+            s.send(msg)
+            s.settimeout(0.1)
+            early_hints = RawResponse(s.recv(118))
+            s.settimeout(1)
+            pause = False
+            try:
+                s.recv(4096)
+            except OSError:
+                pause = True
+            self.assertTrue(pause)
+            s.settimeout(None)
+            response = RawResponse(s.recv(4096))
+        print_log("\nGot Raw HTTP 103 hints", early_hints.raw_bytes)
+        print_log("\nGot Raw HTTP response", response.raw_bytes)
+        self.assertEqual(early_hints.status_code, 103)
+        self.assertEqual(early_hints.headers["Content-Type"], "text/plain or application/json")
+        self.assertEqual(early_hints.headers["Link"], "</script.js>; rel=preload; as=script")
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(response.content, b"Hello world!")
+
     def test_send_request_with_query(self):
         response = self.kphp_server.http_request_raw([b"GET /status?foo=bar&baz=gaz HTTP/1.1"])
         self.assertEqual(response.status_code, 200)