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• Series column ：flask Framework quick start
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Preface

Today is a brief introduction flask Methods for exception handling in , It belongs to the knowledge point that is less popular , Because we use python Knowledge to achieve these needs processing , But we still need to learn , Because he can help us deal with exceptions , Instead of exception handling in each view .

HTTP Exception active throw

• abort Method
  Throw a given status code HTTPException Or specify the response , For example, you want to terminate a request with a page that does not find an exception , You can call abort(404)
• Parameters
  code-HTTP Error status code of . Can only throw http Error code for protocol .

# Import Flask Classes and request object 
from flask import Flask,request,abort
app = Flask(__name__)


@app.route('/articles')
def get_articles():
    channel_id = request.args.get('channel_id')
    if channel_id is None:
        abort(400)   #400 Bad Request
    return 'you want get articles of channel {}'.format(channel_id)
# Flask Application's run Method start up web The server 
if __name__ == '__main__':
    app.run(port=8000)

Capture the error

• errorhandler Decorator
  Register an error handler , When the program throws the specified error status code , Will call the method decorated by the decorator .
• Parameters
  code_or_exception - HTTP Error status code or specified exception .
• For example, the unified processing status code is 500 The error of gives users a good prompt .

@app.errorhandler(500)
def internal_server_err(e):
    return " Server moved "

• Catch the specified exception

@app.errorhandler(ZeroDivisionError)
def zero_division_err(e):
    return " Divisor cannot be zero "

example ：

# Import Flask class 
from flask import Flask
app = Flask(__name__)

@app.errorhandler(ZeroDivisionError)
def zero_division_err(e):
    #  there e It's an exception object 
    print(e)
    return " Divisor cannot be zero "

@app.route("/")
def index():
    s = 1/0
    return s
# Flask Application's run Method start up web The server 
if __name__ == '__main__':
    app.run(port=8000)

As can be seen from the figure , If you encounter an exception, you will immediately stop executing the current view , Instead, execute the corresponding exception handling view .

Conclusion

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