moved from Flask to http.server to support multiple clients

2018-09-19 07:31:02 +01:00
parent 514b50ff88
commit 482fdc3da9
1 changed files with 170 additions and 78 deletions
--- a/md2html/md2html.py
+++ b/md2html/md2html.py
@@ -1,16 +1,20 @@
 #!/usr/bin/env python3

 import argparse
+import hashlib
 import sys
+import threading
+from http.server import ThreadingHTTPServer, BaseHTTPRequestHandler
+from os.path import basename, dirname, abspath
+from urllib.parse import urlparse
+
 import markdown
-from os.path import basename, dirname
-import json

 TEMPLATE = """
 <!DOCTYPE html>
 <html>
 <head>
-    <link href="http://netdna.bootstrapcdn.com/twitter-bootstrap/2.3.0/css/bootstrap-combined.min.css" rel="stylesheet">
+    {css}
    <style>
        body {{
            font-family: sans-serif;
@@ -30,10 +34,25 @@ TEMPLATE = """
 </head>
 <body>
    <script type=\"text/javascript\">
-        let eventSource = new EventSource("/stream");
-        eventSource.addEventListener('reload', function(e) {{
-                window.location.reload(true);
-        }});
+        function req(first) {{
+            var xmlhttp = new XMLHttpRequest();
+            xmlhttp.onload = function() {{
+                if (xmlhttp.status == 200) {{
+                    document.querySelector("div.container").innerHTML = xmlhttp.responseText;
+                }} else if(xmlhttp.status == 304) {{
+                }} else {{
+                    console.log(xmlhttp.status, xmlhttp.statusText);
+                }}
+                req(false);
+            }};
+            xmlhttp.onerror = function() {{
+                console.log(xmlhttp.status, xmlhttp.statusText);
+                setTimeout(req, 1000, false);
+            }};
+            xmlhttp.open("GET", first ? "/markdown" : "/reload", true);
+            xmlhttp.send();
+        }}
+        req(true);
    </script>
    <div class="container">
        {content}
@@ -42,20 +61,144 @@ TEMPLATE = """
 </html>
 """

+def create_css_tag(url_list):
+    result = ''
+    for url in url_list:
+        result += '<link href="%s" rel="stylesheet">' % url
+    return result

-class ServerSentEvent(object):
+def compile_html(mdfile=None, extensions=None, raw=None, stylesheet=(), **kwargs):
+    html = None
+    with mdfile and open(mdfile, 'r') or sys.stdin as instream:
+        html = markdown.markdown(instream.read(), extensions=extensions, output_format='html5')
+    if raw:
+        doc = html
+    else:
+        doc = TEMPLATE.format(content=html, css=create_css_tag(stylesheet))
+    return doc

-    def __init__(self, id=None, event=None, data=None, retry=1000):
-        self.id = id
-        self.event = event
-        self.data = json.dumps(data)
-        self.retry = retry
+class MarkdownHTTPServer(ThreadingHTTPServer):

-    def encode(self):
-        if not self.data:
-            return ""
-        lines = [f"{key}: {value}" for key, value in vars(self).items() if value]
-        return "%s\n\n" % "\n".join(lines)
+    def __init__(self, mdfile, extensions=(), stylesheet=(), handler=BaseHTTPRequestHandler, interface="127.0.0.1", port=8080):
+        import inotify
+        import inotify.adapters
+        import signal
+
+        self.stop = False
+        def sigint_handler(signum, frame):
+            self.stop = True
+
+        handlers = (sigint_handler, signal.getsignal(signal.SIGINT))
+        signal.signal(signal.SIGINT, lambda signum, frame: [handler(signum, frame) for handler in handlers])
+
+        self.mdfile = mdfile
+        self.extensions = extensions
+        self.stylesheet = stylesheet
+        self.condition_variable = threading.Condition()
+        self.hash = None
+        self.etag = None
+        def watch_file():
+            watcher = inotify.adapters.Inotify()
+            watcher.add_watch(dirname(abspath(self.mdfile)))
+            target_file = basename(self.mdfile)
+            while True:
+                if self.stop:
+                    break
+                for event in watcher.event_gen(yield_nones=True, timeout_s=1):
+                    if not event:
+                        continue
+                    (_, event_type, path, filename) = event
+                    if filename == target_file and len(set(event_type).intersection(
+                            {'IN_CLOSE_WRITE'})):
+                        self.condition_variable.acquire()
+                        if self.update_file_digest():
+                            self.condition_variable.notify_all()
+                        self.condition_variable.release()
+
+        file_watcher = threading.Thread(target=watch_file)
+        file_watcher.start()
+        super().__init__((interface, port), handler)
+
+    def update_file_digest(self):
+        md5 = hashlib.md5()
+        with open(self.mdfile, 'rb') as mdfile:
+            md5.update(mdfile.read())
+        digest = md5.digest()
+        if not self.hash or self.hash != digest:
+            self.hash = digest
+            self.etag = md5.hexdigest()
+            return True
+        else:
+            return False
+
+
+class MarkdownRequestHandler(BaseHTTPRequestHandler):
+
+    status_map = {
+        200: "OK",
+        204: "No Content",
+        304: "Not Modified",
+        400: "Bad Request",
+        401: "Unauthorized",
+        404: "Not Found",
+        499: "Service Error",
+        500: "Internal Server Error",
+        501: "Not Implemented",
+        503: "Service Unavailable"
+    }
+
+    def answer(self, code, reply=None, content_type="text/plain",
+               headers=()):
+        output = self.wfile
+        if not reply:
+            reply = MarkdownRequestHandler.status_map[code]
+        try:
+            self.send_response(code, MarkdownRequestHandler.status_map[code])
+            for header in headers:
+                self.send_header(*header)
+            self.send_header("Content-Type", content_type)
+            self.send_header('Content-Length', len(reply))
+            self.end_headers()
+            output.write(reply.encode("UTF-8"))
+            output.flush()
+        except BrokenPipeError:
+            pass
+
+    def markdown_answer(self):
+        if not self.server.etag:
+            self.server.condition_variable.acquire()
+            self.server.update_file_digest()
+            self.server.condition_variable.release()
+        self.answer(200, headers=(('Etag', self.server.etag),),
+                    reply=compile_html(mdfile=self.server.mdfile, extensions=self.server.extensions, raw=True),
+                    content_type='text/html')
+
+    def do_GET(self):
+        path = urlparse(self.path)
+        if path.path == '/':
+            self.answer(200, reply=TEMPLATE.format(content='', css=create_css_tag(self.server.stylesheet)),
+                             content_type='text/html')
+        elif path.path == '/markdown':
+            self.markdown_answer()
+        elif path.path == '/reload':
+            if 'If-None-Match' not in self.headers or self.headers['If-None-Match'] != self.server.etag:
+                self.markdown_answer()
+            else:
+                self.server.condition_variable.acquire()
+                self.server.condition_variable.wait(timeout=10)
+                self.server.condition_variable.release()
+                if self.server.stop:
+                    self.answer(503)
+                elif self.headers['If-None-Match'] == self.server.etag:
+                    self.answer(304)
+                else:
+                    self.answer(200, headers=(('Etag', self.server.etag),),
+                                     reply=compile_html(mdfile=self.server.mdfile,
+                                                        extensions=self.server.extensions,
+                                                        raw=True),
+                                     content_type='text/html')
+        else:
+            self.answer(404)

 def parse_args(args=None):
    parser = argparse.ArgumentParser(description='Make a complete, styled HTML document from a Markdown file.')
@@ -68,7 +211,6 @@ def parse_args(args=None):

    try:
        import inotify
-        import flask
        import gevent
        import signal
        parser.add_argument('-w', '--watch', action='store_true',
@@ -77,77 +219,27 @@ def parse_args(args=None):
                            help='Specify http server port (defaults to 5000)')
        parser.add_argument('-i', '--interface', default='',
                            help='Specify http server listen interface (defaults to localhost)')
+        parser.add_argument('-s', '--stylesheet', nargs='+',
+                            default=['http://netdna.bootstrapcdn.com/twitter-bootstrap/2.3.0/css/bootstrap-combined.min.css'],
+                            help='Specify a list of stylesheet URLs to add to the html page')
    except ImportError:
        pass
    return parser.parse_args(args)

-def compile_html(mdfile=None, extensions=None, raw=None, **kwargs):
-    html = None
-    with mdfile and open(mdfile, 'r') or sys.stdin as instream:
-        html = markdown.markdown(instream.read(), extensions=extensions, output_format='html5')
-    if raw:
-        doc = html
-    else:
-        doc = TEMPLATE.format(**dict(content=html))
-    return doc
-
 def write_html(out=None, **kwargs):
    doc = compile_html(**kwargs)
    with (out and open(out, 'w')) or sys.stdout as outstream:
        outstream.write(doc)

 def main(args=None):
-    import signal
    args = parse_args(args)
-    exit = False
-    def sigint_handler(signum, frame):
-        nonlocal exit
-        exit = True
-    handlers = (sigint_handler, signal.getsignal(signal.SIGINT))
-    signal.signal(signal.SIGINT, lambda signum, frame: [handler(signum, frame) for handler in handlers])
    if hasattr(args, 'watch') and args.watch:
-        import threading
-        from flask import Flask, Response
-        from gevent.pywsgi import WSGIServer
-        condition_variable = threading.Condition()
-        def watch_file():
-            import inotify.adapters
-            nonlocal condition_variable, exit
-            watcher = inotify.adapters.Inotify()
-            watcher.add_watch(dirname(args.mdfile))
-            target_file = basename(args.mdfile)
-            while True:
-                if exit:
-                    break
-                for event in watcher.event_gen(yield_nones=True, timeout_s=1):
-                    if not event:
-                        continue
-                    (_, event_type, path, filename) = event
-                    if filename == target_file and len(set(event_type).intersection(
-                            {'IN_CREATE', 'IN_MODIFY', 'IN_CLOSE_WRITE'})):
-                        condition_variable.acquire()
-                        condition_variable.notify_all()
-                        condition_variable.release()
-
-        file_watcher = threading.Thread(target=watch_file)
-        file_watcher.start()
-        app = Flask(__name__)
-        @app.route('/')
-        def get():
-            return Response(compile_html(**vars(args)), mimetype='text/html')
-
-        @app.route("/stream")
-        def stream():
-            nonlocal condition_variable
-            def gen():
-                while True:
-                    condition_variable.acquire()
-                    condition_variable.wait()
-                    sse = ServerSentEvent(event='reload')
-                    return sse.encode()
-            return Response(gen(), mimetype="text/event-stream")
-
-        server = WSGIServer((args.interface, args.port), app, environ={'wsgi.multithread': True})
+        server = MarkdownHTTPServer(args.mdfile,
+                                    extensions=args.extensions,
+                                    stylesheet=args.stylesheet,
+                                    interface=args.interface,
+                                    port=args.port,
+                                    handler=MarkdownRequestHandler)
        server.serve_forever()
    else:
        write_html(**vars(args))