Flask 面试题与答案

问题 36. Describe Flask memory management.

Memory management handles memory allocation in Python. Flask has a built-in garbage collector. It collects all wastage data and makes the space free. It manages memory by private heap space. This is not accessible by developers.

Few of them are accessed by users by using a few API tools. All data allocation is done by Flask memory management.

问题 37. What do you know about the validators class of WTForms in Flask?

A Validator can take the input to check if it meets some criteria like string limit with returns. In case of failure, a validation error will come. This is a straightforward method. In Flask there are a few validator classes of WTForms. They are:

1. DataRequired: Checks the input field.
2. Email: It checks the email id conventions.
3. IP Address: It checks the IP address.
4. Length: It validates the string length with the given range.
5. NumberRange: It validates the number in the input field with the given range.
6. URL: Checks the URL input field.

问题 38. Can we get any visitor\'s IP address in Flask? How to get any visitor\'s IP address in Flask?

Yes, we can do it. Request.remoote_addr is useful to get the IP address in Flask. An example is given below:

From flask import request
From flask import jsonify

@app.route(\"/get_user_ip\",method=[\"GET\"]
def get_user_ip():
  return jsonify({\'ip\': request.remote_addr}), 200

问题 39. Explain Flask error handlers?

Generally, an HTTP error code will be returned when one error comes. Suppose the error code is within 400 to 499; then it is sure that a mistake is happening in the client-side request. Otherwise, if the error code is within 500 to 599, the error comes from a server-side request.

HTTP error code can show custom error pages to the user. This HTTPS error code is not set to the error handler’s code. While returning a message from the error handler, we have to include it.

问题 40. What type of Applications can we create with Flask?

With Flask, we can create almost all types of web applications. We can create Single Page Application, RESTful API based Applications, SAS applications, Small to medium size websites, static websites, Microservices, and serverless apps.

Flask is so versatile and flexible as it can be integrated with other technologies very quickly to achieve the same. 

For example, Flask can be combined with the NodeJS serverless, AWS lambda, and similar other third party services to build new-age systems.