[PYTHON] When you want to send an object with requests using flask

Overview

** Set up a server with the python ** web framework ** flask ** and point to the ** set up endpoint with some object ** (for example, a string, a list, an object of your own class) * A story when you want to send * **.

I think I often forget it every time, so I will summarize it here.

Conclusion for busy people

** Sender ** is

1. Make what you want to send into a character string
2. Put it in a dictionary
3. json.dumps()

I think it's easiest (for me) to send it.

The ** receiver ** receives the data and does the work done by the sender in reverse.

1. Receive data with `` `request.data```
2. Use `json.loads ()` to return from the string to the dictionary.
3. Extract the value from the dictionary.
4. Return the value to its original type.

How to do

The flow is like this. An overview. I often use the method of finally turning the object into a string, putting that string in a dict, json.dumps, and then sending it.

Sender.py

〜〜〜〜
What you want to send= something

case1 isinstance(What you want to send,Some class object):　## もしWhat you want to sendがオブジェクトのとき
if you want to send can be binalized: ##If the object can be binary
        'pickle.dumps()Binary the object with(byte)Let's.'
        my_binary = pickle.dumps(What you want to send)
        GO_TO case2

    else: ##If the object cannot be binary
        'Make it binary in some way, or in the case of your own class object,
You need to write a serialize function. For example, a function that writes all the member variables of a class to a dictionary. For example, to_dict()Implement the function.'
        my_binary =What you want to send.to_dict()
        GO_TO case4

case2 isinstance(What you want to send, byte): ## もしWhat you want to sendがbyteのとき
    'Base64 what you want to send.b64encode()Let's make it a character string with.'
    my_str = base64.b64encode(What you want to send)
    GO_TO case3

case3 isinstance(What you want to send, str): ## もしWhat you want to sendがstr（文字列）のとき
    'Let's put it in the dictionary.'
    my_dict = {"my_object":What you want to send}
    GO_TO case4


case4 isinstance(What you want to send, dict): ## もしWhat you want to sendがすでにdictのとき
    'What you want to send json.dumps()Then you're ready to go.'
What you want to send= json.dumps(What you want to send)
    EXIT_CASE



assert type(What you want to send) =String(str), 'Please go back to the beginning.'

## print(What you want to send)
## >>> '{"my_object": my_value}'

requests.post(url="<Destination endpoint>",What you want to send,
                  headers={'Content-Type': 'application/json'})

Recipient.py

〜〜〜〜
@app.route('/receive')
def receive():
    data = request.data ##"What you want to send" sent by post is request.You can receive it with data.
    data = json.loads(data)['my_object'] ##First json.Return to the dictionary with loads,
##key is my_value of object(What was sent in the form of a string)To receive.

if data binary(byte)When you want to return to: 
        'base64 data.b64decode()Let's decode to byte with.'
        data2 = base64.b64decode(data)
        
When you want to return elif data to a class object:
if pickle.When you can return with loads:
            data3 = pickle.loads(data2)
else If pickle cannot be used with an object of your own class:
            'Deserialization function by itself, dict_to_obj()Let's implement a function like this and revert to the original class object'
            data3 = dict_to_obj(data2)

Summary

This time, I summarized how to post an object to the endpoint set up in flask.

This time around here.

end.