add server.py

It runs a web server and imports the request handling classes from
get.py directly, hence eliminating the performance culprit (which was
the `import` processing for each request).

4 files changed, 76 insertions, 9 deletions

diff --git a/.gitignore b/.gitignore
index e69de29..c18dd8d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -0,0 +1 @@
+__pycache__/
diff --git a/cgi-bin/get.py b/cgi-bin/get.py
index 3831812..1453dc2 100755
--- a/cgi-bin/get.py
+++ b/cgi-bin/get.py
@@ -10,6 +10,7 @@ import cgi
 from collections import namedtuple
 from concurrent.futures import ThreadPoolExecutor
 from enum import Enum
+import http.server
 import json
 import os
 import pwd
@@ -38,16 +39,43 @@ class Response:
     def __init__(self, data):
         self.data = data
 
-    def print(self):
-        print("Content-Type: text/html; charset=utf-8")
-        print()
-        if self.data is not None:
-            print(self.dump_json(self.data))
+    def headers(self):
+        yield 'Content-Type', 'text/html; charset=utf-8'
 
     @staticmethod
     def dump_json(data):
         return json.dumps(data, ensure_ascii=False)
 
+    def body(self):
+        return self.dump_json(self.data)
+
+    def write_as_cgi_script(self):
+        self.write_headers_as_cgi_script()
+        self.write_body_as_cgi_script()
+
+    def write_headers_as_cgi_script(self):
+        for name, val in self.headers():
+            print(f'{name}: {val}')
+        print()
+
+    def write_body_as_cgi_script(self):
+        if self.data is not None:
+            print(self.body())
+
+    def write_as_request_handler(self, handler):
+        handler.send_response(http.server.HTTPStatus.OK)
+        self.write_headers_as_request_handler(handler)
+        self.write_body_as_request_handler(handler)
+
+    def write_headers_as_request_handler(self, handler):
+        for name, val in self.headers():
+            handler.send_header(name, val)
+        handler.end_headers()
+
+    def write_body_as_request_handler(self, handler):
+        if self.data is not None:
+            handler.wfile.write(self.body().encode(errors='replace'))
+
 
 def run_do(*args, **kwargs):
     output = subprocess.run(args, stdin=DEVNULL, stdout=PIPE, stderr=STDOUT, universal_newlines=True, **kwargs)
@@ -318,6 +346,12 @@ class Request(Enum):
     def __str__(self):
         return self.value
 
+    @staticmethod
+    def from_http_path(path):
+        if not path or path[0] != '/':
+            raise ValueError('HTTP path must start with a forward slash /')
+        return Request(path[1:])
+
     def process(self):
         if self is Request.STATUS:
             return StatusTask().complete()
@@ -331,7 +365,7 @@ class Request(Enum):
 def process_cgi_request():
     params = cgi.FieldStorage()
     what = params['what'].value
-    Request(what).process().print()
+    Request(what).process().write_as_cgi_script()
 
 
 def main():
diff --git a/index.html b/index.html
index 8c46b82..35d118e 100644
--- a/index.html
+++ b/index.html
@@ -76,7 +76,7 @@ function set_top(data) {
 }
 
 function refresh_top() {
-    $.get('cgi-bin/get.sh?what=top', function(data) {
+    $.get('top', function(data) {
         set_top(JSON.parse(data));
     });
 }
@@ -162,7 +162,7 @@ function set_users(data) {
 }
 
 function refresh_status() {
-    $.get('cgi-bin/get.sh?what=status', function(data) {
+    $.get('status', function(data) {
         data = JSON.parse(data);
         set_top(data['top']);
         set_hostname(data['hostname']);
@@ -172,7 +172,7 @@ function refresh_status() {
 }
 
 function refresh_timers() {
-    $.get('cgi-bin/get.sh?what=timers', function(data) {
+    $.get('timers', function(data) {
         data = JSON.parse(data);
         set_system(data['system']);
         set_users(data['user']);
diff --git a/server.py b/server.py
new file mode 100755
index 0000000..9533be7
--- /dev/null
+++ b/server.py
@@ -0,0 +1,32 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2021 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is part of the "linux-status" project.
+# For details, see https://github.com/egor-tensin/linux-status.
+# Distributed under the MIT License.
+
+import http.server
+
+from get import Request
+
+
+class RequestHandler(http.server.CGIHTTPRequestHandler):
+    def do_GET(self):
+        try:
+            request = Request.from_http_path(self.path)
+        except ValueError:
+            return super().do_GET()
+        request.process().write_as_request_handler(self)
+
+
+def main():
+    addr = ('', 18101)
+    httpd = http.server.ThreadingHTTPServer(addr, RequestHandler)
+    try:
+        httpd.serve_forever()
+    except KeyboardInterrupt:
+        print('\nKeyboard interrupt received, exiting...')
+
+
+if __name__ == '__main__':
+    main()