A first, semi-sane integration of Jinja2 templates

matemat/webserver/httpd.py

@@ -12,6 +12,8 @@ from http.cookies import SimpleCookie
 from uuid import uuid4
 from datetime import datetime, timedelta
 
+import jinja2
+
 from matemat import __version__ as matemat_version
 from matemat.exceptions import HttpException
 from matemat.webserver import RequestArguments
@@ -35,7 +37,8 @@ _PAGELET_PATHS: Dict[str, Callable[[str,  # HTTP method (GET, POST, ...)
                                     Dict[str, str]],  # Response headers
                                    Union[  # Return type: either a response body, or a redirect
                                        bytes, str,  # Response body: will assign HTTP/1.0 200 OK
-                                       Tuple[int, str]  # Redirect: First element must be 301, second the redirect path
+                                       Tuple[int, str],  # Redirect: First element must be 301, second the redirect path
+                                       Tuple[str, Dict[str, Any]]  # Jinja template name and kwargs
                                    ]]] = dict()
 
 # Inactivity timeout for client sessions
@@ -65,6 +68,8 @@ def pagelet(path: str):
         returns:      One of the following:
                         - A HTTP Response body as str or bytes
                         - A HTTP redirect: A tuple of 301 (an int) and the path to redirect to (a str)
+                        - A Jinja template call: A tuple of the template name (a string) and the template rendering
+                              arguments (a kwargs dict)
         raises:       HttpException: If a non-200 HTTP status code should be returned
 
     :param path: The path to register the function for.
@@ -77,7 +82,8 @@ def pagelet(path: str):
                                     Dict[str, str]],
                                    Union[
                                        bytes, str,
-                                       Tuple[int, str]
+                                       Tuple[int, str],
+                                       Tuple[str, Dict[str, Any]]
                                    ]]):
         # Add the function to the dict of pagelets
         _PAGELET_PATHS[path] = fun
@@ -97,13 +103,18 @@ class MatematHTTPServer(HTTPServer):
     def __init__(self,
                  server_address: Any,
                  handler: Type[BaseHTTPRequestHandler],
-                 webroot: str,
+                 staticroot: str,
+                 templateroot: str,
                  bind_and_activate: bool = True) -> None:
         super().__init__(server_address, handler, bind_and_activate)
         # Resolve webroot directory
-        self.webroot = os.path.abspath(webroot)
+        self.webroot = os.path.abspath(staticroot)
         # Set up session vars dict
         self.session_vars: Dict[str, Tuple[datetime, Dict[str, Any]]] = dict()
+        # Set up the Jinja2 environment
+        self.jinja_env: jinja2.Environment = jinja2.Environment(
+            loader=jinja2.FileSystemLoader(os.path.abspath(templateroot))
+        )
 
 
 class MatematWebserver(object):
@@ -121,13 +132,18 @@ class MatematWebserver(object):
         server.start()
     """
 
-    def __init__(self, listen: str = '::', port: int = 80, webroot: str = './webroot') -> None:
+    def __init__(self,
+                 listen: str = '::',
+                 port: int = 80,
+                 staticroot: str = './static',
+                 templateroot: str = './templates') -> None:
         """
         Instantiate a MatematWebserver.
 
-        :param listen: The IPv4 or IPv6 address to listen on
-        :param port: The TCP port to listen on
-        :param webroot: Path to the webroot directory
+        :param listen: The IPv4 or IPv6 address to listen on.
+        :param port: The TCP port to listen on.
+        :param staticroot: Path to the static webroot directory.
+        :param templateroot: Path to the Jinja2 templates root directory.
         """
         if len(listen) == 0:
             # Empty string should be interpreted as all addresses
@@ -137,7 +153,7 @@ class MatematWebserver(object):
             # Rewrite IPv4 address to IPv6-mapped form
             listen = f'::ffff:{listen}'
         # Create the http server
-        self._httpd = MatematHTTPServer((listen, port), HttpHandler, webroot)
+        self._httpd = MatematHTTPServer((listen, port), HttpHandler, staticroot, templateroot)
 
     def start(self) -> None:
         """
@@ -202,8 +218,12 @@ class HttpHandler(BaseHTTPRequestHandler):
         if session_id in self.server.session_vars:
             del self.server.session_vars[session_id]
 
-    @staticmethod
-    def _parse_pagelet_result(pagelet_res: Union[bytes, str, Tuple[int, str]], headers: Dict[str, str]) \
+    def _parse_pagelet_result(self,
+                              pagelet_res: Union[bytes,  # Response body as bytes
+                                                 str,  # Response body as str
+                                                 Tuple[int, str],  # Redirect
+                                                 Tuple[str, Dict[str, Any]]],  # Jinja template name, kwargs dict
+                              headers: Dict[str, str]) \
             -> Tuple[int, bytes]:
         """
         Process the return value of a pagelet function call.
@@ -218,12 +238,19 @@ class HttpHandler(BaseHTTPRequestHandler):
         # The HTTP Response body, defaults to None
         data: Union[bytes, str] = None
         if isinstance(pagelet_res, tuple):
-            # If the return type is a tuple, the first element must be 301 (the HTTP Redirect status code)
+            # If the return type is a tuple, it has to be either a redirect, in which case the first element must be
+            # int(301), or it is a template call, in which casse the first element must be the template name and the
+            # second element must be the kwargs dict to the template's render function
             head, tail = pagelet_res
-            if head == 301:
+            if head == 301 and isinstance(tail, str):
                 # Set the HTTP Response Status Code, and the redirect header
                 hsc = 301
                 headers['Location'] = tail
+            elif isinstance(head, str) and isinstance(tail, dict):
+                # Load the Jinja2 template and render it with the provided arguments
+                template = self.server.jinja_env.get_template(head)
+                tail['matemat_version'] = self.server_version
+                data = template.render(**tail)
             else:
                 raise TypeError(f'Return value of pagelet not understood: {pagelet_res}')
         elif isinstance(pagelet_res, str) or isinstance(pagelet_res, bytes):
@@ -271,7 +298,7 @@ class HttpHandler(BaseHTTPRequestHandler):
             # Call the pagelet function
             pagelet_res = _PAGELET_PATHS[path](method, path, args, self.session_vars, headers)
             # Parse the pagelet's return value, vielding a HTTP status code and a response body
-            hsc, data = HttpHandler._parse_pagelet_result(pagelet_res, headers)
+            hsc, data = self._parse_pagelet_result(pagelet_res, headers)
             # Send the HTTP status code
             self.send_response(hsc)
             # Format the session cookie timeout string and send the session cookie header

matemat/webserver/pagelets/login.py

@@ -13,40 +13,17 @@ def login_page(method: str,
                args: RequestArguments,
                session_vars: Dict[str, Any],
                headers: Dict[str, str])\
-        -> Union[bytes, str, Tuple[int, str]]:
+        -> Union[bytes, str, Tuple[int, str], Tuple[str, Dict[str, Any]]]:
     if 'user' in session_vars:
         return 301, '/'
     if method == 'GET':
-        data = '''
-        <DOCTYPE html>
-        <html>
-            <head>
-                <title>Matemat</title>
-                <style>
-                    body {{
-                        color: #f0f0f0;
-                        background: #000000;
-                    }};
-                </style>
-            </head>
-            <body>
-                <h1>Matemat</h1>
-                {msg}
-                <form action="/login" method="post">
-                    Username: <input type="text" name="username"/><br/>
-                    Password: <input type="password" name="password" /><br/>
-                    <input type="submit" value="Login"/>
-                </form>
-            </body>
-        </html>
-        '''
-        return data.format(msg=str(args.msg) if 'msg' in args else '')
+        return 'login.html', {}
     elif method == 'POST':
         with MatematDatabase('test.db') as db:
             try:
                 user: User = db.login(str(args.username), str(args.password))
             except AuthenticationError:
-                return 301, '/login?msg=Username%20or%20password%20wrong.%20Please%20try%20again.'
+                return 301, '/login'
             session_vars['user'] = user
         return 301, '/'
     raise HttpException(405)

matemat/webserver/pagelets/logout.py

@@ -10,7 +10,7 @@ def logout(method: str,
            args: RequestArguments,
            session_vars: Dict[str, Any],
            headers: Dict[str, str])\
-        -> Union[bytes, str, Tuple[int, str]]:
+        -> Union[bytes, str, Tuple[int, str], Tuple[str, Dict[str, Any]]]:
     if 'user' in session_vars:
         del session_vars['user']
     return 301, '/'

matemat/webserver/pagelets/main.py

@@ -12,41 +12,12 @@ def main_page(method: str,
               args: RequestArguments,
               session_vars: Dict[str, Any],
               headers: Dict[str, str])\
-        -> Union[bytes, str, Tuple[int, str]]:
-    data = '''
-    <DOCTYPE html>
-    <html>
-        <head>
-            <title>Matemat</title>
-            <style>
-                body {{
-                    color: #f0f0f0;
-                    background: #000000;
-                }};
-            </style>
-        </head>
-        <body>
-            <h1>Matemat</h1>
-            {user}
-            <ul>
-            {list}
-            </ul>
-        </body>
-    </html>
-    '''
+        -> Union[bytes, str, Tuple[int, str], Tuple[str, Dict[str, Any]]]:
     with MatematDatabase('test.db') as db:
         if 'user' in session_vars:
             user: User = session_vars['user']
             products = db.list_products()
-            plist = '\n'.join([f'<li/> <b>{p.name}</b> ' +
-                               f'{p.price_member//100 if user.is_member else p.price_non_member//100}' +
-                               f'.{p.price_member%100 if user.is_member else p.price_non_member%100}'
-                               for p in products])
-            uname = f'<b>{user.name}</b> <a href="/logout">(Logout)</a>'
-            data = data.format(user=uname, list=plist)
+            return 'main.html', {'user': user, 'list': products}
         else:
             users = db.list_users()
-            ulist = '\n'.join([f'<li/> <b><a href=/touchkey?username={u.name}>{u.name}</a></b>' for u in users])
-            ulist = ulist + '<li/> <a href=/login>Password login</a>'
-            data = data.format(user='', list=ulist)
-    return data
+            return 'main.html', {'list': users}

matemat/webserver/pagelets/touchkey.py

@@ -1,6 +1,8 @@
 
 from typing import Any, Dict, Tuple, Union
 
+import urllib.parse
+
 from matemat.exceptions import AuthenticationError, HttpException
 from matemat.webserver import pagelet, RequestArguments
 from matemat.primitives import User
@@ -13,39 +15,18 @@ def touchkey_page(method: str,
                   args: RequestArguments,
                   session_vars: Dict[str, Any],
                   headers: Dict[str, str])\
-        -> Union[bytes, str, Tuple[int, str]]:
+        -> Union[bytes, str, Tuple[int, str], Tuple[str, Dict[str, Any]]]:
     if 'user' in session_vars:
         return 301, '/'
     if method == 'GET':
-        data = '''
-        <DOCTYPE html>
-        <html>
-            <head>
-                <title>Matemat</title>
-                <style>
-                    body {{
-                        color: #f0f0f0;
-                        background: #000000;
-                    }};
-                </style>
-            </head>
-            <body>
-                <h1>Matemat</h1>
-                <form action="/touchkey" method="post">
-                    <input type="hidden" name="username" value="{username}"/><br/>
-                    Touchkey: <input type="password" name="touchkey" /><br/>
-                    <input type="submit" value="Login"/>
-                </form>
-            </body>
-        </html>
-        '''
-        return data.format(username=str(args.username) if 'username' in args else '')
+        return 'touchkey.html', {'username': str(args.username)} if 'username' in args else {}
     elif method == 'POST':
         with MatematDatabase('test.db') as db:
             try:
                 user: User = db.login(str(args.username), touchkey=str(args.touchkey))
             except AuthenticationError:
-                return 301, f'/touchkey?username={args["username"]}&msg=Please%20try%20again.'
+                quoted = urllib.parse.quote_plus(bytes(args.username))
+                return 301, f'/touchkey?username={quoted}'
             session_vars['user'] = user
         return 301, '/'
     raise HttpException(405)

templates/login.html

@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<html>
+    <head>
+        <title>Matemat</title>
+        <style>
+            body {
+                color: #f0f0f0;
+                background: #000000;
+            }
+        </style>
+    </head>
+    <body>
+        <h1>Matemat</h1>
+        <form action="/login" method="post">
+            Username: <input type="text" name="username"/><br/>
+            Password: <input type="password" name="password" /><br/>
+            <input type="submit" value="Login"/>
+        </form>
+    </body>
+</html>

templates/main.html

@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<html>
+    <head>
+        <title>Matemat</title>
+        <style>
+            body {
+                color: #f0f0f0;
+                background: #000000;
+            }
+        </style>
+    </head>
+    <body>
+        <h1>Matemat</h1>
+        {{ user|default("") }}
+        <ul>
+        {% if user is defined %}
+            {% for l in list %}
+                <li/> <b>{{ l.name }}</b>
+                {% if user.is_member %}
+                    {{ l.price_member }}
+                {% else %}
+                    {{ l.price_non_member }}
+                {% endif %}
+            {% endfor %}
+        {% else %}
+            {% for l in list %}
+            <li/> <b><a href="/touchkey?username={{ l.name }}">{{ l.name }}</a></b>
+            {% endfor %}
+            <li/> <a href="/login">Password login</a>
+        {% endif %}
+        </ul>
+    </body>
+</html>

templates/touchkey.html

@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<html>
+    <head>
+        <title>Matemat</title>
+        <style>
+            body {
+                color: #f0f0f0;
+                background: #000000;
+            }
+        </style>
+    </head>
+    <body>
+        <h1>Matemat</h1>
+        <form action="/touchkey" method="post">
+            <input type="hidden" name="username" value="{{ username }}"/><br/>
+            Touchkey: <input type="password" name="touchkey" /><br/>
+            <input type="submit" value="Login"/>
+        </form>
+    </body>
+</html>