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Upload and download filask files

2022-07-24 23:45:00 【Clean night mortal dust】

Methods to introduce

use Flask Handling file uploads is easy , Just make sure you don't forget in your HTML Set... In the form enctype=“multipart/form-data” Properties will do . Otherwise, the browser will not transfer your file .

Uploaded files are stored in memory or in a temporary location on the file system . You can request objects by files Property to access the uploaded file . Every uploaded file is stored in this Dictionary type attribute . This attribute is basic and standard Python file object , One more Used to save uploaded files to the file system of the server save() Method

If you want to know the name of the file in the client system before uploading , have access to filename attribute . But keep in mind that this value is Can be forged , Never trust this value . If you want to use the file name of the client as the file name on the server , Can pass Werkzeug Provided secure_filename() function

Of uploaded files html

The following code has ‘/upload’ URL The rules , The rule is in templates The folder shows ‘upload.html’, as well as ‘/upload-file’ URL The rules , Used to invoke uploader() Function to handle the upload process .
‘upload.html’ There is a file selector button and a submit button

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>File upload</title>
</head>
<body>
    <form action="http://localhost:5000/uploader" method="POST" enctype="multipart/form-data">
        <input type="file" name="file">
        <input type="submit" value=" Submit ">
    </form>
</body>
</html>

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Upload files

After selecting files , Click Submit .

Form post Method call ‘/upload_file’ URL.

The underlying function uploader() Perform save operation .

from flask import Flask, render_template, request
from werkzeug.utils import secure_filename
import os

app = Flask(__name__)
#  Define the storage path of uploaded files , There must be a peer directory  upload
app.config['UPLOAD_FOLDER'] = 'upload/'


#  Set the upload size to 16M
# app.config['MAX_CONTENT_LENGTH']=16 * 1000 * 1000

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


@app.route('/uploader', methods=['GET', 'POST'])
def uploader():
    if request.method == 'POST':
        f = request.files['file']
        print(request.files)
        f.save(os.path.join(app.config['UPLOAD_FOLDER'], secure_filename(f.filename)))
        return 'file uploaded successfully'
    else:
        return render_template('upload.html')


if __name__ == '__main__':
    app.run(debug=True)

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Download the file

We need to provide services for uploaded files , Enable it to be downloaded by users . We will define a download_file View to provide services for uploading files in the folder , url_for(“download_file”, name=name) Generate download according to the file name URL

from flask import send_from_directory

@app.route('/download/<name>')
def download_file(name):
    return send_from_directory(app.config["UPLOAD_FOLDER"], name,as_attachment=True)

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complete python Code

from flask import Flask, render_template, request, send_from_directory
from werkzeug.utils import secure_filename
import os

app = Flask(__name__)
#  Define the storage path of uploaded files , There must be a peer directory  upload
app.config['UPLOAD_FOLDER'] = 'upload/'


#  Set the upload size to 16M
# app.config['MAX_CONTENT_LENGTH']=16 * 1000 * 1000

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


@app.route('/uploader', methods=['GET', 'POST'])
def uploader():
    if request.method == 'POST':
        f = request.files['file']
        print(request.files)
        f.save(os.path.join(app.config['UPLOAD_FOLDER'], secure_filename(f.filename)))
        return 'file uploaded successfully'
    else:
        return render_template('upload.html')


@app.route('/download/<name>')
def download_file(name):
    return send_from_directory(app.config['UPLOAD_FOLDER'], name, as_attachment=True)


if __name__ == '__main__':
    app.run(debug=True)