Author: John Au-Yeung

Sometimes, we want to cast Python Flask form value to int.

In this article, we’ll look at how to cast Python Flask form value to int.

How to cast Python Flask form value to int?

To cast Python Flask form value to int, we call the int function.

For instance, we write

@app.route("/getpersonbyid", methods=["POST"])
def get_person_by_id():
    personId = int(request.form["person-id"])
    return str(personId)

to create the /getpersonbyid route with the get_person_by_id function.

In it, we get the form value from the form field with the name attribute set to person-id from request.form.

Then we convert the value to an int with int.

Conclusion

To cast Python Flask form value to int, we call the int function.

Sometimes, we want to upload image in Flask and Python.

In this article, we’ll look at how to upload image in Flask and Python.

How to upload image in Flask and Python?

To upload image in Flask and Python, we can get the uploaded file from the request.files property.

For instance, we write

import os
from flask import Flask, request

UPLOAD_FOLDER = "./upload"

app = Flask(__name__)
app.config["UPLOAD_FOLDER"] = UPLOAD_FOLDER


@app.route("/", methods=["GET", "POST"])
def upload_file():
    if request.method == "POST":
        if "file1" not in request.files:
            return "there is no file1 in form!"
        file1 = request.files["file1"]
        path = os.path.join(app.config["UPLOAD_FOLDER"], file1.filename)
        file1.save(path)
        return "ok"
    return """
    <h1>Upload new File</h1>
    <form method="post" enctype="multipart/form-data">
      <input type="file" name="file1">
      <input type="submit">
    </form>
    """


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

to add the upload_file function that’s mapped to the / route.

In it, we check for the file uploaded with the request.files dictionary.

We check for the file with key file1 with "file1" not in request.files.

If it exists, then we get the file’s path with

os.path.join(app.config["UPLOAD_FOLDER"], file1.filename)

Then we save the file with file1.save(path).

If the request method isn’t 'POST', then we show use the file upload form to let them upload the file.

Conclusion

To upload image in Flask and Python, we can get the uploaded file from the request.files property.

Sometimes, we want to set response headers in Flask and Python.

In this article, we’ll look at how to set response headers in Flask and Python.

How to set response headers in Flask and Python?

To set response headers in Flask and Python, we set the headers property of the response object.

For instance, we write

@app.route("/")
def home():
    resp = make_response("hello")
    resp.headers["Access-Control-Allow-Origin"] = "*"
    return resp

to call make_response to create response object that returns a string response.

Then we set the Access-Control-Allow-Origin header with

resp.headers["Access-Control-Allow-Origin"] = "*"

Finally, we return the resp object in the home route.

Conclusion

To set response headers in Flask and Python, we set the headers property of the response object.