ernstki · May 28, 2021 00:36
diff --git a/flask-upload-download.py b/flask-upload-download.py
 ##
 ##  Take a file uploaded by the user, process it, and offer the result for
 ##  download
 ##
 ##  For a more complete example (with better input checking), see:
 ##  https://flask.palletsprojects.com/en/1.1.x/patterns/fileuploads/
 ##
 ##  Run like this:
 ##    $ mkdir uploads
 ##    $ FLASK_APP=flask-upload-download.py flask run
 ##

 import os
 import mimetypes
 import subprocess

 from flask import Flask, abort, redirect, url_for, request, render_template, \
                  send_from_directory
 from jinja2 import Template
 from werkzeug.utils import secure_filename

 # Flask configuration
 MAX_CONTENT_LENGTH = 1024*1024  # 1 MB

 inputpage = """<html>
  <body>
  <h1>Select a file to upload:</h1>
  <form action="/wordcount" method="POST", enctype="multipart/form-data">
    <input type="file" name="inputfile">
    <br><br>
    <input type="submit" value="Upload">
  </form>
 </html>"""

 outputpage = Template("""<html>
  <body>
    <h1>Your file, <tt>{{ filename }}</tt>, has {{ linecount }} lines.</h1>
    <a href="/download/{{ filename }}">Download results for {{ filename }}</a>
  </body>
 </html>""")

 errorpage = Template("""<html>
  <body>
   <h1>{{ error }}</h1>
   <p>{{ detail }}</p>
  </body>
 </html>""")

 app = Flask(__name__)
 app.config.from_object(__name__)


 @app.errorhandler(400)
 def bad_request(detail):
    return render_template(errorpage, error='Input Error', detail=detail)


 @app.errorhandler(500)
 def internal_error(detail):
    return render_template(errorpage, error='Internal Error', detail=detail)


 @app.route('/')
 def index():
    return inputpage


 @app.route('/wordcount', methods=['POST'])
 def process_upload():
    infile = request.files['inputfile']
    # 'uploads' subdirectory must already exist
    infilename = secure_filename(infile.filename)
    inpath = os.path.join('uploads', infilename)
    infile.save(inpath)

    mimetype = mimetypes.guess_type(inpath)

    if not mimetype[0]:
        abort(400, f"Unrecognized MIME type; input file must be plain text.")

    # quick sanity check to make sure it's a plain (uncompressed) text file
    if not mimetype[0].startswith('text/') and mimetype[1] is None:
        abort(400, f"Input file must be plain text (got {mimetype[0]}).")

    try:
        p = subprocess.run(['wc', '-l', inpath], check=True,
                           encoding='utf8', capture_output=True)
    except subprocess.SubprocessError as e:
        abort(500, f"Problem processing input file (<tt>{e.stderr}</tt>).")

    # overwrite the input file with the output of 'wc -l'
    with open(inpath, 'w') as outf:
        outf.writelines(p.stdout)

    return redirect(url_for('process_upload') + '/' + infilename)


 @app.route('/wordcount/<filename>', methods=['GET'])
 def display_result(filename):
    filename = secure_filename(filename)
    wcfile = os.path.join('uploads', filename)

    if not os.path.isfile(wcfile):
        abort(400, f"No such file <tt>{filename}</tt>.")

    # read the linecount out of the file in 'uploads/' subdirectory
    with open(wcfile, 'r') as f:
        count = f.readline().strip().split(' ')[0]

    return render_template(outputpage, filename=filename, linecount=count)


 @app.route('/download/<filename>')
 def download_result(filename):
    filename = secure_filename(filename)
    wcfile = os.path.join('uploads', filename)

    if not os.path.isfile(wcfile):
        abort(400, f"No such file <tt>{filename}</tt>.")

    return send_from_directory('uploads', filename, as_attachment=True)
	##
	## Take a file uploaded by the user, process it, and offer the result for
	## download
	##
	## For a more complete example (with better input checking), see:
	## https://flask.palletsprojects.com/en/1.1.x/patterns/fileuploads/
	##
	## Run like this:
	## $ mkdir uploads
	## $ FLASK_APP=flask-upload-download.py flask run
	##

	import os
	import mimetypes
	import subprocess

	from flask import Flask, abort, redirect, url_for, request, render_template, \
	send_from_directory
	from jinja2 import Template
	from werkzeug.utils import secure_filename

	# Flask configuration
	MAX_CONTENT_LENGTH = 1024*1024 # 1 MB

	inputpage = """<html>
	<body>
	<h1>Select a file to upload:</h1>
	<form action="/wordcount" method="POST", enctype="multipart/form-data">
	<input type="file" name="inputfile">
	<br><br>
	<input type="submit" value="Upload">
	</form>
	</html>"""

	outputpage = Template("""<html>
	<body>
	<h1>Your file, <tt>{{ filename }}</tt>, has {{ linecount }} lines.</h1>
	<a href="/download/{{ filename }}">Download results for {{ filename }}</a>
	</body>
	</html>""")

	errorpage = Template("""<html>
	<body>
	<h1>{{ error }}</h1>
	<p>{{ detail }}</p>
	</body>
	</html>""")

	app = Flask(__name__)
	app.config.from_object(__name__)


	@app.errorhandler(400)
	def bad_request(detail):
	return render_template(errorpage, error='Input Error', detail=detail)


	@app.errorhandler(500)
	def internal_error(detail):
	return render_template(errorpage, error='Internal Error', detail=detail)


	@app.route('/')
	def index():
	return inputpage


	@app.route('/wordcount', methods=['POST'])
	def process_upload():
	infile = request.files['inputfile']
	# 'uploads' subdirectory must already exist
	infilename = secure_filename(infile.filename)
	inpath = os.path.join('uploads', infilename)
	infile.save(inpath)

	mimetype = mimetypes.guess_type(inpath)

	if not mimetype[0]:
	abort(400, f"Unrecognized MIME type; input file must be plain text.")

	# quick sanity check to make sure it's a plain (uncompressed) text file
	if not mimetype[0].startswith('text/') and mimetype[1] is None:
	abort(400, f"Input file must be plain text (got {mimetype[0]}).")

	try:
	p = subprocess.run(['wc', '-l', inpath], check=True,
	encoding='utf8', capture_output=True)
	except subprocess.SubprocessError as e:
	abort(500, f"Problem processing input file (<tt>{e.stderr}</tt>).")

	# overwrite the input file with the output of 'wc -l'
	with open(inpath, 'w') as outf:
	outf.writelines(p.stdout)

	return redirect(url_for('process_upload') + '/' + infilename)


	@app.route('/wordcount/<filename>', methods=['GET'])
	def display_result(filename):
	filename = secure_filename(filename)
	wcfile = os.path.join('uploads', filename)

	if not os.path.isfile(wcfile):
	abort(400, f"No such file <tt>{filename}</tt>.")

	# read the linecount out of the file in 'uploads/' subdirectory
	with open(wcfile, 'r') as f:
	count = f.readline().strip().split(' ')[0]

	return render_template(outputpage, filename=filename, linecount=count)


	@app.route('/download/<filename>')
	def download_result(filename):
	filename = secure_filename(filename)
	wcfile = os.path.join('uploads', filename)

	if not os.path.isfile(wcfile):
	abort(400, f"No such file <tt>{filename}</tt>.")

	return send_from_directory('uploads', filename, as_attachment=True)