Create simple_getfile.py

Author: peijunz

Diff for: simple_getfile.py

@@ -0,0 +1,121 @@
+from flask import Flask, render_template, send_file, redirect, Response
+import os
+import sys
+
+app = Flask(__name__)
+
+CWD = '.'
+
+TXT_FILES = ['py', 'txt', 'md', 'yaml', 'json', 'html', 'log']
+MIMETYPES = {
+    'html': 'text/html',
+    'json': 'application/json',
+    }
+
+def get_mimetype(format):
+    """Return mimetype metadata according to file format"""
+    return MIMETYPES.get(format, 'text/plain')
+
+def get_format(fname):
+    """Infer file format from file name"""
+    return fname.split('.')[-1]
+
+def simplify_logic_path(url_path: str) -> str:
+    """Simplify the logic path.
+
+    Input should not contain leading slash, and the simplified path
+    will also not contain leading /. The simplified path will not contain
+    trailing / unless original path does.
+
+    Examples
+    =========
+    '/'         => 无效输入
+    ''          => ''
+    'a/'        => 'a/'
+    'a/b/..'    => 'a'
+    'a/../..'   => ''
+    """
+    assert (not url_path) or url_path[0] != '/', "path should not contain leading /"
+    stack = []
+    for sub in url_path.split('/'):
+        if sub == '..':
+            if stack:
+                stack.pop()
+        elif sub != '.' and sub:
+            stack.append(sub)
+    if url_path.endswith('/'):
+        stack.append('')
+    return '/'.join(stack)
+
+def path_exists(fs_path):
+    """Decide that the dir or file exists
+
+    fs_path indicates directory or file by trailing slash
+    """
+    if fs_path.endswith('/') and not os.path.isdir(fs_path):
+        return False
+    if not fs_path.endswith('/') and not os.path.isfile(fs_path):
+        return False
+    return True
+
+def redirect_and_404(url_path):
+    """重定向和404等异常路径"""
+    # simplify path.
+    simplified = simplify_logic_path(url_path)
+    if simplified != url_path:
+        return redirect(simplified)
+
+    fs_path = os.path.join(CWD, simplified)
+
+    # redirect directory with no slash /
+    if not fs_path.endswith('/') and os.path.isdir(fs_path):
+        return redirect(url_path + '/')
+
+    # report 404 if file/dir is not found.
+    if not path_exists(fs_path):
+        return render_template('404.html'), 404
+
+def handle_directory(url_path, fs_path):
+    """Handle directory"""
+    # fs_path points to a dir
+    subs = ['../']
+    subs += [x.name + '/' if x.is_dir() else x.name for x in os.scandir(fs_path)]
+    subs.sort()
+
+    # index.html is supplied
+    if 'index.html' in subs:
+        with open(fs_path + 'index.html') as page:
+            contents = page.read()
+        return contents
+    return render_template("directfor.html", cur_dir = '/' + url_path, subs = subs)
+
+def handle_file(url_path, fs_path):
+    """Handle file"""
+    format = get_format(fs_path)
+    # send file
+    if format not in TXT_FILES:
+        return send_file(fs_path, as_attachment=True)
+
+    # send contents
+    with open(fs_path) as f:
+        contents = f.read()
+    return Response(contents, status=200, mimetype=get_mimetype(format))
+
+@app.route('/', defaults = {'url_path':''})
+@app.route('/<path:url_path>')
+def direct(url_path):
+    redirect_response = redirect_and_404(url_path)
+    if redirect_response:
+        return redirect_response
+
+    # path is already simplified, so we just join current to get actual path
+    fs_path = os.path.join(CWD, url_path)
+    if fs_path.endswith('/'):
+        return handle_directory(url_path, fs_path)
+    return handle_file(url_path, fs_path)
+
+
+if __name__ == "__main__":
+    if len(sys.argv) > 1:
+        CWD = sys.argv[1]
+    app.run(debug = True, port=5000)