Say hello to qtwasmserver

Development web server for web applications. Supports
http and https. Sets COOP and COEP headers.

The web server script supports certificate generation using
mkcert (github.com/FiloSottile/mkcert). Briefly, mkcert
supports generating server certificates for the current
local ip address(es), using a certificate authority
which can be installed on devices where the app should
run.

The COOP and COEP headers are required to enable the
SharedArrayBuffer API, which is required for Emscripten’s
pthreads implementation.

The server serves the current directory on localhost
by default. Use the “-a” argument to bind to an additional
address, or "--all” to bind to all IPv4 addresses found on
local network interfaces. Change the directory by passing
it as a positional argument.

Task-number: QTBUG-79087
Change-Id: Id0cba649e42af53ed8106e336a77e78398bcf901
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: David Skoland <david.skoland@qt.io>

2 files changed, 161 insertions, 0 deletions

diff --git a/util/wasm/qtwasmserver/Pipfile b/util/wasm/qtwasmserver/Pipfile
new file mode 100644
index 0000000000..ef542c1048
--- /dev/null
+++ b/util/wasm/qtwasmserver/Pipfile
@@ -0,0 +1,12 @@
+[[source]]
+url = "https://pypi.org/simple"
+verify_ssl = true
+name = "pypi"
+
+[packages]
+netifaces = "*"
+
+[dev-packages]
+
+[requires]
+python_version = "3.9"
diff --git a/util/wasm/qtwasmserver/qtwasmserver.py b/util/wasm/qtwasmserver/qtwasmserver.py
new file mode 100755
index 0000000000..dc4c4129ac
--- /dev/null
+++ b/util/wasm/qtwasmserver/qtwasmserver.py
@@ -0,0 +1,149 @@
+#!/usr/bin/env python3
+#############################################################################
+##
+## Copyright (C) 2021 The Qt Company Ltd.
+## Contact: https://www.qt.io/licensing/
+##
+## This file is part of the plugins of the Qt Toolkit.
+##
+## $QT_BEGIN_LICENSE:GPL-EXCEPT$
+## Commercial License Usage
+## Licensees holding valid commercial Qt licenses may use this file in
+## accordance with the commercial license agreement provided with the
+## Software or, alternatively, in accordance with the terms contained in
+## a written agreement between you and The Qt Company. For licensing terms
+## and conditions see https://www.qt.io/terms-conditions. For further
+## information use the contact form at https://www.qt.io/contact-us.
+##
+## GNU General Public License Usage
+## Alternatively, this file may be used under the terms of the GNU
+## General Public License version 3 as published by the Free Software
+## Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+## included in the packaging of this file. Please review the following
+## information to ensure the GNU General Public License requirements will
+## be met: https://www.gnu.org/licenses/gpl-3.0.html.
+##
+## $QT_END_LICENSE$
+##
+#############################################################################
+
+import os
+import socket
+import ssl
+import sys
+import threading
+from http.server import ThreadingHTTPServer, SimpleHTTPRequestHandler
+from subprocess import run
+import netifaces as ni
+import argparse
+
+# This script implements a web server which serves the content of the current
+# working directory using the http and secure https protocols. The server is
+# intented to be used as a development server.
+#
+# Https certificates are generated using the 'mkcert' utility. You should generate
+# a certificate authority first, see the mkcert documentation at
+# https://github.com/FiloSottile/mkcert
+#
+# The server sets the COOP and COEP headers, which are required to enable multithreading.
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="Run a minimal HTTP(S) server to test Qt for WebAssembly applications.",
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
+    )
+    parser.add_argument(
+        "--port",
+        "-p",
+        help="Port on which to listen for HTTP and HTTPS (PORT + 1)",
+        type=int,
+        default=8000,
+    )
+    parser.add_argument(
+        "--address",
+        "-a",
+        help="Address on which to listen for HTTP and HTTPS, in addition to localhost",
+        action="append",
+    )
+    parser.add_argument(
+        "--all",
+        help="Start web server which binds to all local interfaces, instead of locahost only",
+        action="store_true",
+    )
+    parser.add_argument(
+        "path", help="The directory to serve", nargs="?", default=os.getcwd()
+    )
+
+    args = parser.parse_args()
+    http_port = args.port
+    https_port = http_port + 1
+    all_addresses = args.all
+    cmd_addresses = args.address or []
+    serve_path = args.path
+
+    addresses = ["127.0.0.1"] + cmd_addresses
+    if all_addresses:
+        addresses += [
+            addr[ni.AF_INET][0]["addr"]
+            for addr in map(ni.ifaddresses, ni.interfaces())
+            if ni.AF_INET in addr
+        ]
+    addresses = sorted(set(addresses))  # deduplicate
+
+    # Generate a https certificate for "localhost" and selected addresses. This
+    # requires that the mkcert utility is installed, and that a certificate
+    # authority key pair (rootCA-key.pem and rootCA.pem) has been generated. The
+    # certificates are written to /tmp, where the https server can find them
+    # later on.
+    cert_base_path = "/tmp/qtwasmserver-certificate"
+    cert_file = f"{cert_base_path}.pem"
+    cert_key_file = f"{cert_base_path}-key.pem"
+    addresses_string = f"localhost {' '.join(addresses)}"
+    ret = run(
+        f"mkcert -cert-file {cert_file} -key-file {cert_key_file} {addresses_string}",
+        shell=True,
+    )
+    has_certificate = ret.returncode == 0
+    if not has_certificate:
+        print(
+            "Warning: mkcert is not installed or was unable to create a certificate. Will not start HTTPS server."
+        )
+
+    # Http request handler which sends headers required to enable multithreading using SharedArrayBuffer.
+    class MyHTTPRequestHandler(SimpleHTTPRequestHandler):
+        def __init__(self, request, client_address, server):
+            super().__init__(request, client_address, server, directory=serve_path)
+
+        def end_headers(self):
+            self.send_header("Cross-Origin-Opener-Policy", "same-origin")
+            self.send_header("Cross-Origin-Embedder-Policy", "require-corp")
+            self.send_header("Cross-Origin-Resource-Policy", "cross-origin")
+            SimpleHTTPRequestHandler.end_headers(self)
+
+    # Serve cwd from http(s)://address:port, with certificates from certdir if set
+    def serve_on_thread(address, port, secure):
+        httpd = ThreadingHTTPServer((address, port), MyHTTPRequestHandler)
+        if secure:
+            httpd.socket = ssl.wrap_socket(
+                httpd.socket,
+                certfile=cert_file,
+                keyfile=cert_key_file,
+                server_side=True,
+            )
+        thread = threading.Thread(target=httpd.serve_forever)
+        thread.start()
+
+    # Start servers
+    print(f"Serving at:")
+    for address in addresses:
+        print(f"  http://{address}:{http_port}")
+        serve_on_thread(address, http_port, False)
+
+    if has_certificate:
+        for address in addresses:
+            print(f"  https://{address}:{https_port}")
+            serve_on_thread(address, https_port, True)
+
+
+if __name__ == "__main__":
+    main()