Allow to upload file and download from given link

5 files changed, 245 insertions, 0 deletions

diff --git a/src/db.py b/src/db.py
new file mode 100644
index 0000000..8aa20f8
--- /dev/null
+++ b/src/db.py
@@ -0,0 +1,20 @@
+import secrets
+
+def insert_file(conn, filename: str, expiration_days: int, content_length: int):
+    cur = conn.cursor()
+    file_id = secrets.token_urlsafe()
+    cur.execute(
+        'INSERT INTO files(id, filename, created, expires, content_length) VALUES(?, ?, datetime(), datetime(datetime(), ?), ?)',
+        (file_id, filename, f'+{expiration_days} days', content_length)
+    )
+    conn.commit()
+    return file_id
+
+def get_file(conn, file_id: str):
+    cur = conn.cursor()
+    res = cur.execute(
+        'SELECT filename, expires, content_length FROM files WHERE id = ?',
+        (file_id,)
+    )
+    return res.fetchone()
+
diff --git a/src/main.py b/src/main.py
new file mode 100644
index 0000000..56c8e9e
--- /dev/null
+++ b/src/main.py
@@ -0,0 +1,24 @@
+import http.server
+import logging
+import os
+import sys
+
+import server
+
+logger = logging.getLogger(__name__)
+hostName = os.environ['HOST']
+serverPort = int(os.environ['PORT'])
+
+if __name__ == '__main__':
+    logging.basicConfig(stream=sys.stdout, level=logging.INFO)
+    webServer = http.server.HTTPServer((hostName, serverPort), server.MyServer)
+    logger.info('Server started at http://%s:%s.' % (hostName, serverPort))
+
+    try:
+        webServer.serve_forever()
+    except KeyboardInterrupt:
+        pass
+
+    webServer.server_close()
+    conn.close()
+    logger.info('Server stopped.')
diff --git a/src/server.py b/src/server.py
new file mode 100644
index 0000000..2cd6741
--- /dev/null
+++ b/src/server.py
@@ -0,0 +1,85 @@
+import http.server
+import logging
+import os
+import sqlite3
+import tempfile
+
+import db
+import templates
+import utils
+
+logger = logging.getLogger(__name__)
+conn = sqlite3.connect('db.sqlite3')
+files_directory = 'download'
+authorized_key = os.environ['KEY']
+
+class MyServer(http.server.BaseHTTPRequestHandler):
+    def do_GET(self):
+        match self.path:
+            case '/':
+                self._serve_str(templates.index, 200, 'text/html')
+            case '/main.js':
+                self._serve_file('public/main.js', 'application/javascript')
+            case '/main.css':
+                self._serve_file('public/main.css', 'text/css')
+            case path:
+                prefix = f'/{files_directory}/'
+                if path.startswith(prefix):
+                    file_id = path[len(prefix):]
+                    res = db.get_file(conn, file_id)
+                    if res is None:
+                        self._serve_str(templates.not_found, 404, 'text/html')
+                    else:
+                        filename, _, content_length = res
+                        path = os.path.join(files_directory, file_id)
+                        headers = [
+                            ('Content-Disposition', f'attachment; filename={filename}'),
+                            ('Content-Length', content_length)
+                        ]
+                        self._serve_file(path, 'application/octet-stream', headers)
+                else:
+                    file_id = path[1:]
+                    res = db.get_file(conn, file_id)
+                    if res is None:
+                        self._serve_str(templates.not_found, 404, 'text/html')
+                    else:
+                        filename, expires, _ = res
+                        href = os.path.join(files_directory, file_id)
+                        self._serve_str(templates.download(href, filename, expires), 200, 'text/html')
+
+    def do_POST(self):
+        key = self.headers['X-Key']
+        if not key == authorized_key:
+            logging.info('Unauthorized to upload file: wrong key')
+            self._serve_str('Unauthorized', 401)
+
+        else:
+            logging.info('Uploading file')
+            content_length = int(self.headers['content-length'])
+            filename = utils.sanitize_filename(self.headers['X-FileName'])
+            expiration = self.headers['X-Expiration']
+
+            with tempfile.NamedTemporaryFile(delete = False) as tmp:
+              utils.transfer(self.rfile, tmp, content_length = content_length)
+
+            logging.info('File uploaded')
+            file_id = db.insert_file(conn, filename, expiration, content_length)
+            os.makedirs(files_directory, exist_ok=True)
+            os.rename(tmp.name, os.path.join(files_directory, file_id))
+
+            self._serve_str(file_id, 200)
+
+    def _serve_str(self, s, code, content_type='text/plain'):
+        self.send_response(code)
+        self.send_header('Content-type', content_type)
+        self.end_headers()
+        self.wfile.write(bytes(s, 'utf-8'))
+
+    def _serve_file(self, filename, content_type, headers = []):
+        self.send_response(200)
+        self.send_header('Content-type', content_type)
+        for header_name, header_value in headers:
+            self.send_header(header_name, header_value)
+        self.end_headers()
+        with open(filename, 'rb') as f:
+            utils.transfer(f, self.wfile)
diff --git a/src/templates.py b/src/templates.py
new file mode 100644
index 0000000..1308fc0
--- /dev/null
+++ b/src/templates.py
@@ -0,0 +1,97 @@
+import html
+
+page: str = '''
+    <!doctype html>
+    <html lang="fr">
+    <meta charset="utf-8">
+    <meta name="viewport" content="width=device-width">
+
+    <title>Files</title>
+    <link rel="stylesheet" href="/main.css">
+    <script src="/main.js"></script>
+
+    <a href="/">
+        <h1>Files</h1>
+    </a>
+'''
+
+index: str = f'''
+    {page}
+
+    <form>
+        <label>
+            File
+            <input type="file" name="file" required>
+        </label>
+
+        <label>
+            Expiration
+            <select name="expiration">
+                <option value="1">1 day</option>
+                <option value="2">2 days</option>
+                <option value="3">3 days</option>
+                <option value="4">4 days</option>
+                <option value="5">5 days</option>
+                <option value="6">6 days</option>
+                <option value="7" selected>7 days</option>
+                <option value="8">8 days</option>
+                <option value="9">9 days</option>
+                <option value="10">10 days</option>
+                <option value="11">11 days</option>
+                <option value="12">12 days</option>
+                <option value="13">13 days</option>
+                <option value="14">14 days</option>
+                <option value="15">15 days</option>
+                <option value="16">16 days</option>
+                <option value="17">17 days</option>
+                <option value="18">18 days</option>
+                <option value="19">19 days</option>
+                <option value="20">20 days</option>
+                <option value="21">21 days</option>
+                <option value="22">22 days</option>
+                <option value="23">23 days</option>
+                <option value="24">24 days</option>
+                <option value="25">25 days</option>
+                <option value="26">26 days</option>
+                <option value="27">27 days</option>
+                <option value="28">28 days</option>
+                <option value="29">29 days</option>
+                <option value="30">30 days</option>
+                <option value="31">31 days</option>
+            </select>
+        </label>
+
+        <label>
+            Key
+            <input type="password" name="key" required>
+        </label>
+
+        <div class="g-Loading">
+            <div class="g-Spinner"></div>
+            Uploading…
+        </div>
+
+        <div class="g-Error">
+        </div>
+
+        <input type="submit" value="Upload">
+    </form>
+'''
+
+def download(href: str, filename: str, expires: str) -> str:
+    return f'''
+        {page}
+
+        <div>
+            <a class="g-Link" href="{html.escape(href)}">{html.escape(filename)}</a>
+            <div>
+                Expires: {html.escape(expires)}
+            </div>
+        </div>
+    '''
+
+not_found: str = f'''
+    {page}
+
+    Sorry, the file you are looking for can not be found. It may have already expired.
+'''
diff --git a/src/utils.py b/src/utils.py
new file mode 100644
index 0000000..ccf92c0
--- /dev/null
+++ b/src/utils.py
@@ -0,0 +1,19 @@
+import io
+
+def transfer(reader, writer, content_length = None, buffer_size = io.DEFAULT_BUFFER_SIZE):
+    if content_length is None:
+        while (data := reader.read(buffer_size)):
+            writer.write(data)
+    else:
+        remaining = content_length
+        while remaining > 0:
+            size = min(buffer_size, remaining)
+            writer.write(reader.read(size))
+            remaining -= size
+
+def sanitize_filename(s: str) -> str:
+    return '.'.join([sanitize_filename_part(p) for p in s.split('.')])
+
+def sanitize_filename_part(s: str) -> str:
+    alnum_or_space = ''.join([c if c.isalnum() else ' ' for c in s])
+    return '-'.join(alnum_or_space.split())