Retrieving JSON in Python in response to POST

问题:

I'm trying to get a JSON from a server to use it in a Python code. For test purposes, I did POST by curl:

$ curl -u trial:trial -H "Content-Type: application/json"
-X POST -d '{"BP_TSM":"22"}' http://some-host --trace-ascii -

My Java code seems to correctly handle creating JSON as a response. Please look at the result of curl command:

 == Info: About to connect() to localhost port 8080 (#0)
== Info:   Trying ::1...
== Info: Connected to localhost (::1) port 8080 (#0)
== Info: Server auth using Basic with user 'trial'
=> Send header, 224 bytes (0xe0)
0000: POST /get/auth HTT
0040: P/1.1
0047: Authorization: Basic dHJpYWw6dHJpYWw=
006e: User-Agent: curl/7.29.0
0087: Host: localhost:8080
009d: Accept: */*
00aa: Content-Type: application/json
00ca: Content-Length: 15
00de: 
=> Send data, 15 bytes (0xf)
0000: {"BP_TSM":"22"}
== Info: upload completely sent off: 15 out of 15 bytes
<= Recv header, 23 bytes (0x17)
0000: HTTP/1.1 202 Accepted
<= Recv header, 34 bytes (0x22)
0000: Server: Payara Micro #badassfish
<= Recv header, 32 bytes (0x20)
0000: Content-Type: application/json
<= Recv header, 37 bytes (0x25)
0000: Date: Thu, 22 Mar 2018 14:30:43 GMT
<= Recv header, 21 bytes (0x15)
0000: Content-Length: 108
<= Recv header, 29 bytes (0x1d)
0000: X-Frame-Options: SAMEORIGIN
<= Recv header, 2 bytes (0x2)
0000: 
<= Recv data, 108 bytes (0x6c)
0000: {"title":"Free Music Archive - Albums","message":"","total":"112
0040: 59","total_pages":2252,"page":1,"limit":"5"}
{"title":"Free Music Archive - Albums","message":"","total":"11259","total_pages

":2252,"page":1,"limit":"5"}== Info: Connection #0 to host localhost left intact

Now I would like Python script be able to receive the same message that curl did. I wrote the following Python code (note I'm not Python developer):

import pickle
import requests
import codecs
import json
from requests.auth import HTTPBasicAuth
from random import randint
req = requests.get('server/get/auth', auth=HTTPBasicAuth('trial', 'trial'))
return pickle.dumps(req)

Unfortunately, I get error message 'unicode' object has no attribute 'copy' when return pickle.dumps(req) command is executed. I also tried using return json.dumps(req) but this time I get another error:

Traceback (most recent call last):
  File "/tmp/tmp8DfLJ7/usercode.py", line 16, in the_function
    return json.dumps(req)
  File "/usr/lib64/python2.7/json/__init__.py", line 244, in dumps
    return _default_encoder.encode(obj)
  File "/usr/lib64/python2.7/json/encoder.py", line 207, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/lib64/python2.7/json/encoder.py", line 270, in iterencode
    return _iterencode(o, 0)
  File "/usr/lib64/python2.7/json/encoder.py", line 184, in default
    raise TypeError(repr(o) + " is not JSON serializable")
TypeError: <Response [405]> is not JSON serializable

Do I have some error in Python code or is it fault of my Java server returning incorrect JSON?

回答1:

There are a number of errors in your Python code.

• You are using request.get to POST. Instead, use request.post.
• You are not passing the BP_TSM json string into your request. Use data= in your request.post.
• You are not emulating the -H switch to curl. Use headers= in your request.post.
• You are using pickle for no apparent reason. Don't do that.
• You are using a return statement when you are not in a function. Don't do that. If you want to print to stdout, use print() or sys.stdout.write() instead.
• If you actually want to use the returned variables from the JSON (as opposed to simply printing to stdout), you shoud invoke req.json().

Here is a version of your code with problems addressed.

import requests
import json
import sys
from requests.auth import HTTPBasicAuth

data = '{"BP_TSM": "22"}'                       # curl -d
headers = {'content-type': 'application/json'}  # curl -H
auth = HTTPBasicAuth('trial', 'trial')          # curl -u

req = requests.post(                            # curl -X POST
    'http://httpbin.org/post',
    auth=auth,
    data=data,
    headers=headers)
sys.stdout.write(req.text)         # Display JSON on stdout
returned_data = req.json()
my_ip = returned_data["origin"]    # Query value from JSON
print("My public IP is", my_ip)

回答2:

You're trying to dumps a Response object.

Try returning req.json() or calling json.loads(req.text)

回答3:

In order to load the Json string, you'll need to use json.loads(req.text).

You must also ensure that the req string is valid json.

eg

'{"FOO":"BAR"}'

回答4:

You can use requests.json() method to get json response as dict

req = requests.get('http://yourdomain.com/your/path', auth=HTTPBasicAuth('trial', 'trial'))
mydict = req.json()