Download modified CSV file in Flask

Question

My goal is to run my data de-identifying script and download my de-identified data from Flask. Right now, I have created a page to upload my file onto my web and I want to execute my de-identifying script using the execute button on my HTML and download the file.

My HTML:

{% block title %}Upload{% endblock %}

{% block main %}

<div class="container">
  <div class="row">
    <div class="col">

      <h1>Upload the file</h1>
      <hr>

      <form action="/upload-file" method="POST" enctype="multipart/form-data">

        <div class="form-group">
          <label>Select file</label>
          <div class="custom-file">
            <input type="file" class="custom-file-input" name="Dataset" id="Dataset">
            <label class="custom-file-label" for="Dataset">Select file...</label>
          </div>
        </div>

        <button type="submit" class="btn btn-primary">De-indentify</button>
      </form>

      <form action="/upload-file" method="GET" enctype="multipart/form-data">
        <button type="submit" class="btn btn-primary">Execute</button>
      </form>
      
    </div>
  </div>
</div>

{% endblock %}

My App Flask route:

app.config["FILE_UPLOADS"] = "app/app/static/csv/uploads"
app.config["ALLOWED_FILE_EXTENSIONS"] = ["csv"]


def allowed_file(filename):

    # We only want files with a . in the filename
    if not "." in filename:
        return False

    # Split the extension from the filename
    ext = filename.rsplit(".", 1)[1]

    # Check if the extension is in ALLOWED_IMAGE_EXTENSIONS
    if ext.upper() in app.config["ALLOWED_FILE_EXTENSIONS"]:
        return True
    else:
        return False


@app.route("/upload-file", methods=["GET", "POST"])
def upload_file():

    if request.method == "POST":

        if request.files:

            Dataset = request.files["Dataset"]

            if Dataset.filename == "":
                print("File must have a filename ")
                return redirect(request.url)

            if allowed_file(Dataset.filename):
                print("That file extension is not allowed")
                return redirect(request.url)

            else:
                filename = secure_filename(Dataset.filename)

                Dataset.save(os.path.join(
                    app.config["FILE_UPLOADS"], filename))

            print("Dataset saved")

            return redirect(request.url)
  
    return render_template("public/upload_file.html")

The file that I have uploaded:

Housing,Houseprice,Name,Neighbourhood,State
123556,100000,John,Bloomingdale,Washington
111777,250000,Ian,Bloomingdale,Washington
998273,250000,Tom,Spring Valley,California

My de-identifying script:

import pandas as pd 
import uuid as u 

 # generate a pseudo-identifier sequesnce using python random number generator library uudi.

def uudi_generator(length): 
    uudi_list= list() 
    i=0 
    while i < length: 
        uudi_list.append(u.uuid4()) 
        i+=1
    return uudi_list 

#import dataset 
dataset = pd.read_csv('C:\\mylocation\\housing.csv', index_col=False) 

# pseudo identifier
sLength = len(dataset['Housing']) 
dataset.insert(0, 'uuid', pd.Series(uudi_generator(sLength), index=dataset.index)) 
 

#delete identifiabLe record from dataset 
del dataset['Name'] 
del dataset['Neigbourhood']

score 0 · Answer 1 · answered Sep 01 '20 at 18:02

Try this:

from flask import Response

csv_text = ""
for row in dataset.values:
    csv_text += f"{row[0]},{row[1]},{row[2]},{row[3]}\n"
    
return Response(csv_text, mimetype='text/csv')

You don't even need to del the unwanted columns. Just don't add them in csv_text. You don't really even need pandas. You could read the csv as a text file, split('\n') and add the uuids when you compile the csv_text

Download modified CSV file in Flask

1 Answers1