A minimum-working-example to post PDF data using axios Javascript, and decode/save the PDF data in python Flask

client.ts

import fs from "fs";

// fs.readFile("test.txt", function (err, data) {
//     if (err) throw err;
//     console.log(data);
// });

import axios from 'axios';
import FormData from 'form-data';
import console = require("console");

const filePath = 'python-service/tmp/Zhang_et_al-2014-Journal_of_the_Association_for_Information_Science_and_Technology.pdf';
const imageData = fs.readFileSync(filePath);

const form = new FormData();
form.append('file', imageData, {
    filepath: filePath,
    contentType: 'application/pdf',
});

axios.post('http://localhost:5000/autograb/grobidmetadata', imageData, {
    headers: {'Content-Type': 'application/pdf'},
}).then(response => {
    console.log('success!');
}).catch(err => {
    console.log(err);
});

server.py

import json

from flask import Flask, jsonify, request, abort
from flask_cors import CORS
from util import inference

app = Flask(__name__)  # creates an app object from Flask.
CORS(app)

@app.route('/autograb/grobidmetadata', methods=['POST'])
def parsePDFAndGROBIDExtract():
    # request.form['file'].read().save('tmp/file-to-save.pdf')
    with open('tmp/file_to_save.pdf', 'wb') as f2:
        f2.write(request.data)
    print("request.form['file']", request.form.get("file"))
    print("request.data",request.data)
    # request.data.save("tmp/this.jpg")
    print("request.file",request.files)
    print(request.args)
    # print(request.form['file'])
    return jsonify({"content":"nothing!"})


if __name__ == "__main__":
    app.run()