How to Access Form Values in Flask Routes Without Errors: A Guide to Avoid Empty Dictionaries and 400s

Barbara Streisand
Release: 2024-10-31 21:31:02
Original
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How to Access Form Values in Flask Routes Without Errors: A Guide to Avoid Empty Dictionaries and 400s

Accessing Form Values in Flask Routes

In Flask applications, posting values from an HTML form and accessing them in views is a common task. However, users often encounter issues with empty request.form dictionaries and 400 errors when trying to access form values by ID.

Key Takeaways:

To successfully post and access form values in Flask:

  • Ensure each input field in the HTML form has a unique name attribute. This attribute specifies the key that will be used to identify the corresponding value in the request.form dictionary.
  • In the Flask view, retrieve the form values using request.form.get(key_name). This method safely retrieves the value associated with the specified key or returns None if the key does not exist in the dictionary.

Example:

Consider the following HTML form and Flask view:

<code class="html"><form method="POST">
  <input name="my_input" id="my_input" type="text" value="{{ email }}">
  <input id="my_submit" type="submit" value="Submit">
</form></code>
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<code class="python">@app.route('/page', methods=['POST', 'GET'])
def get_page():
    if request.method == 'POST':
        my_input_value = request.form.get('my_input')
        # Process my_input_value here
    return render_template('page.html')</code>
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By using request.form.get('my_input'), the view safely retrieves the value associated with the 'my_input' key. If the key does not exist in the request.form dictionary, 'None' is returned, preventing 400 errors.

The above is the detailed content of How to Access Form Values in Flask Routes Without Errors: A Guide to Avoid Empty Dictionaries and 400s. For more information, please follow other related articles on the PHP Chinese website!

source:php.cn
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