How to send a pdf file for ajax response using flask?-CodePudding

I am trying to display a pdf file in the browser without downloading it for the user. So currently I have a flask function that can generate a pdf file using FPDF module and I need it to be displayed to the user in a new tab.

The current flask function is

@app.route('/pdf/create', methods=['GET', 'POST'])
def create_pdf():
    if not session.get('email'):
        return redirect(url_for('login_page'))
    email = session.get('email')
    pdf = FPDF('P', 'mm', "A4")
    pdf.add_page()
    .... pdf making ...
    pdf.output(f"pdf/mypdf.pdf")
    return send_file(f"pdf/mypdf.pdf",
                     mimetype='application/pdf',
                     attachment_filename=f"My file.pdf",
                     as_attachment=True,
                     cache_timeout=-1)

I call the ajax function as

$("#viewFile").on("click",function(){

    $.ajax({
      url: "{{url_for('create_pdf')}}",
      type: "get",
      data: {text: mytext},
      success: function(response) {
        window.open(response);
      },
      error: function(xhr) {
        alert("Error: Failed to save notes.");
      }
    });
});

CodePudding user response：

With the parameter as_attachment you can specify whether the browser should save the file or offer it for display. If the value is set to False, the file should be displayed. (See documentation)

The following example also shows you how you can deliver the pdf document without saving it temporarily.
The use of AJAX is not necessary in this case. A simple anchor with a target should do the trick.

Flask (app.py)

from flask import (
    Flask,
    render_template,
    send_file
)
from fpdf import FPDF
import io

app = Flask(__name__)

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

@app.route('/pdf/create')
def create_pdf():
    pdf = FPDF()
    pdf.add_page()
    pdf.set_font('Arial', 'B', 16)
    pdf.cell(40, 10, 'Hello World')

    stream = io.BytesIO(pdf.output(dest='S').encode('latin-1'))
    return send_file(
        stream,
        mimetype='application/pdf',
        attachment_filename='example.pdf',
        as_attachment=False
    )

HTML (templates/index.html)

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title></title>
  </head>
  <body>
    <a href="{{ url_for('create_pdf') }}" target="_blank">Download</a>
  </body>
</html>