将 python 脚本应用到烧瓶

Question

(Python beginner question)

I've built a csv parser that I wanted to build a simple site to allow users to upload a csv and it return the parsed csv.

I'm having trouble understanding how to integrate my parser script into a simple Flask site that generated. I was able to get an upload module working that will consume the csv.

My Flask view looks like this:

import os
from app import app
from flask import render_template, flash, redirect, session, url_for, request, g, send_from_directory
from werkzeug import secure_filename

UPLOAD_FOLDER = '/csv_upload_directory'
ALLOWED_EXTENSION = set(['csv', 'txt'])

def allowed_file(filename):
    return '.' in filename and \
           filename.rsplit('.', 1)[1] in ALLOWED_EXTENSION

@app.route('/', methods=['GET'])
@app.route('/index', methods=['GET'] )
def index():
    return render_template('index.html')


@app.route('/upload', methods=['GET','POST'])
def upload():
    file = request.files['file']
    if file and allowed_file(file.filename):
        filename = secure_filename(file.filename)
        getfile = file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))
        return redirect(url_for('index'))

@app.route('/uploads/<filename>', methods=['GET','POST'])
def uploaded_file(filename):
    return send_from_directory(app.config['UPLOAD_FOLDER'], filename)

My parser script:

def parse(text):
    #states
    is_token = False
    previous_character_is_escape = False
    no_quote_value = True
    quote_value = False

    row_counter = 1

    print "This is row %i" % (row_counter)
    row_counter += 1
    with io.open(text,'rb',newline=None) as f:
        while True:
            byte = f.read(1)
            for i in byte:
                #print "%s,%s" % (no_quote_value,previous_character_is_escape)
                if is_token == False:
                    if i == '"':
                        print '\b' + i,
                        is_token = True
                        no_quote_value = False
                        quote_value = True
                    elif i == '\n':
                        print '\n'
                        print "This is row %i" % (row_counter)
                        row_counter += 1
                    elif i == ',':
                        print '\n' + '\b',
                    elif no_quote_value == True:
                        print '\b' + i,
                        is_token = True
                        quote_value = False
                    else:
                        print '\b' + i,


                elif is_token == True:
                    # start of an escape sequence
                    if i == '\\':
                        print '\b' + i,
                        previous_character_is_escape = True
                    # for line delimiter, the quoted values are being processed outside token
                    elif no_quote_value == True and i == '\n':
                        print '\n'
                        print "This is row %i" % (row_counter)
                        row_counter += 1
                        is_token = False
                    # if token is not a quoted value but ends with quotes, and there is no escape character
                    elif no_quote_value == True and previous_character_is_escape == False and i == '"':
                        print '\b' + i,
                        print "(This is a not a valid token, this is not a quoted value but there is an ending quote)"
                        return False
                    # builds off previous_character_is_escape and captures any escape sequence
                    elif previous_character_is_escape == True:
                        print '\b' + i,
                        previous_character_is_escape = False
                    # this type of quote is the end of token, returns back to other if statement
                    elif previous_character_is_escape == False and i == '"':
                        print '\b' + i,
                        no_quote_value = True
                        quote_value = False
                        is_token = False
                    # if token starts as a quote but ends without quotes
                    elif quote_value == True and previous_character_is_escape == False and i == ',':
                        print '\b' + i,
                        print "(This is not a valid token, there should be a quote at the end of this token)"
                        return False
                    # this comma marks the end of a non quoted token, this invokes a newline
                    elif no_quote_value == True and previous_character_is_escape == False and i == ',':
                        print '\n' + '\b',
                        is_token = False
                    elif no_quote_value == False and i == ',':
                        print '\b' + i,
                    else:
                        print '\b' + i,

Since my parser script is already written to accept a file format, I was thinking of adding a "parse" button that will execute this script on the file that is uploaded and simply print the results on the same page. How do you go about applying my python scripts into the Flask framework?

Answer 1

Once you uploaded your file you can call this URL and get your result.

You can use this function (this is an example which you can change to suit your purpose):

from from_parse_function_file import parse

@app.route('/get_parsed/<filename>')
def get_parsed(filename):
    try:
        file = open(os.path.join(current_app.config.get('UPLOAD_FOLDER'),
                    filename))
    except:
        return abort(404)
    return parse(file.read())

I also changed your parse() function to return a string:

def parse(text):
    #states
    is_token = False
    previous_character_is_escape = False
    no_quote_value = True
    quote_value = False

    row_counter = 1

    result = "This is row %i" % (row_counter)
    row_counter += 1
    with io.open(text,'rb',newline=None) as f:
        while True:
            byte = f.read(1)
            for i in byte:
                #print "%s,%s" % (no_quote_value,previous_character_is_escape)
                if is_token == False:
                    if i == '"':
                        result += '\b' + i,
                        is_token = True
                        no_quote_value = False
                        quote_value = True
                    elif i == '\n':
                        result += '\n'
                        result += "This is row %i" % (row_counter)
                        row_counter += 1
                    elif i == ',':
                        result += '\n' + '\b',
                    elif no_quote_value == True:
                        result += '\b' + i,
                        is_token = True
                        quote_value = False
                    else:
                        result += '\b' + i,


                elif is_token == True:
                    # start of an escape sequence
                    if i == '\\':
                        result += '\b' + i,
                        previous_character_is_escape = True
                    # for line delimiter, the quoted values are being processed outside token
                    elif no_quote_value == True and i == '\n':
                        result += '\n'
                        result += "This is row %i" % (row_counter)
                        row_counter += 1
                        is_token = False
                    # if token is not a quoted value but ends with quotes, and there is no escape character
                    elif no_quote_value == True and previous_character_is_escape == False and i == '"':
                        result += '\b' + i,
                        result += "(This is a not a valid token, this is not a quoted value but there is an ending quote)"
                        return False
                    # builds off previous_character_is_escape and captures any escape sequence
                    elif previous_character_is_escape == True:
                        result += '\b' + i,
                        previous_character_is_escape = False
                    # this type of quote is the end of token, returns back to other if statement
                    elif previous_character_is_escape == False and i == '"':
                        result += '\b' + i,
                        no_quote_value = True
                        quote_value = False
                        is_token = False
                    # if token starts as a quote but ends without quotes
                    elif quote_value == True and previous_character_is_escape == False and i == ',':
                        result += '\b' + i,
                        result += "(This is not a valid token, there should be a quote at the end of this token)"
                        return False
                    # this comma marks the end of a non quoted token, this invokes a newline
                    elif no_quote_value == True and previous_character_is_escape == False and i == ',':
                        result += '\n' + '\b',
                        is_token = False
                    elif no_quote_value == False and i == ',':
                        result += '\b' + i,
                    else:
                        result += '\b' + i,
    return result

The thing I did to your function is to set a result value to things you print in console and then return the result value.