Il caricamento di pdf to sql-alchimia in python utilizzando blob

0

Domanda

Sto cercando di caricare i libri di sqlite3 in forma di pdf. Ho scritto questo codice che carica :

  • autore
  • titolo
  • pdf della storia, ma il blob parte non sembra funzionare qui:
class Book(UserMixin, db.Model):

        id = db.Column(db.Integer, primary_key=True)
        author = db.Column(db.String(50), unique=False)
        title = db.Column(db.String(50), unique=False)
        pdf= db.Column(db.Blob(10000000))
    
    @app.route('/uploadStory', methods=['GET', 'POST'])
    def uploadStory():
        new_book = Book(author=form.author.data, title=form.title.data, pdf=form.pdf.data)
        db.session.add(new_book)
        db.session.commit()

Come faccio a verificare che l'utente è in grado di caricare il libro tramite PDF? Idealmente

  • Voglio agli utenti di caricare tutto il storie
  • Voglio il blob di dimensioni molto grandi
  • Non voglio memorizzare le storie a livello locale e poi utilizzare il percorso
  • Voglio memorizzare utilizzando blob
blob flask python sql
2021-11-20 05:52:53
1

Migliore risposta

0

Non so come eseguire questa operazione utilizzando SQLAlchemy, ma qui è la vaniglia Python/Pallone modo:

from flask import Flask, render_template, request, redirect, url_for
import sqlite3

app = Flask(__name__)

def insert_user_data(author, title, pdf):
    con = sqlite3.connect("user_data.sqlite")
    cur = con.cursor()
    query = """
        INSERT IGNORE INTO user_data (author, title, pdf) VALUES (?, ?, ?);
    """
    cur.execute(query, [author, title, pdf])
    con.commit()


@app.route("/", methods=["GET", "POST"])
def home():
    if request.method == "POST":
        pdf = request.files["pdf"].read()
        author = request.form["author"]
        title = request.form["title"]
        insert_user_data(author, title, pdf)
        return redirect(url_for("home"))

    return render_template("index.html")

Che assume tale schema del DB:

CREATE TABLE IF NOT EXISTS user_data (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    author TEXT,
    title TEXT,
    pdf BLOB
);

E un semplice index.html:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Save PDF</title>
    <style>
        input {
            display: block;
        }
    </style>
</head>
<body>
    <form method="POST" action="{{ url_for('home') }}" enctype="multipart/form-data">
        <input type="text" name="author" placeholder="author" />
        <input type="text" name="title" placeholder="title" />
        <input type="file" name="pdf" />
        <button type="submit">Submit</button>
    </form>
</body>
</html>

Quando ho eseguito questo, e quindi eseguire un altro script per estrarre la pdf dal DB e scrivere in un file (per vedere se ha funzionato), sembra tutto a posto:

import sqlite3

con = sqlite3.connect("user_data.sqlite")
cur = con.cursor()

query = """
    SELECT pdf FROM user_data WHERE id = 1;
"""

result = cur.execute(query).fetchone()[0]

with open("think-python.pdf", mode="wb") as file:
    file.write(result)

Ecco il file risultante struttura:

➜  blob-pdf ls
app.py  main.py  __pycache__  schema.sql  templates  think-python.pdf  user  user_data.sqlite
➜  blob-pdf file think-python.pdf
think-python.pdf: PDF document, version 1.5

Ed ecco il file, dopo aver tirato dal DB:

Think Python

2021-11-20 06:22:13

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