Sending JSON request with Python

Question

I'm new to web services and am trying to send the following JSON based request using a python script:

http://myserver/emoncms2/api/post?apikey=xxxxxxxxxxxxx&json={power:290.4,temperature:19.4}

If I paste the above into a browser, it works as expected. However, I am struggling to send the request from Python. The following is what I am trying:

import json
import urllib2
data = {'temperature':'24.3'}
data_json = json.dumps(data)
host = "http://myserver/emoncms2/api/post"
req = urllib2.Request(host, 'GET', data_json, {'content-type': 'application/json'})
response_stream = urllib2.urlopen(req)
json_response = response_stream.read()

How do I add the apikey data into the request?

Thank you!

Answer 1

Instead of using urllib2, you can use requests. This new python lib is really well written and it's easier and more intuitive to use.

To send your json data you can use something like the following code:

import json
import requests
data = {'temperature':'24.3'}
data_json = json.dumps(data)
payload = {'json_payload': data_json, 'apikey': 'YOUR_API_KEY_HERE'}
r = requests.get('http://myserver/emoncms2/api/post', data=payload)

You can then inspect r to obtain an http status code, content, etc

Answer 2

Even though this doesnt exactly answer OPs question, it should be mentioned here that requests module has a json option that can be used like this:

import requests

requests.post(
    'http://myserver/emoncms2/api/post?apikey=xxxxxxxxxxxxx',
    json={"temperature": "24.3"}
)

which would be equivalent to the curl:

curl 'http://myserver/emoncms2/api/post?apikey=xxxxxxxxxxxxx' \
    -H 'Content-Type: application/json' \
    --data-binary '{"temperature":"24.3"}'

Answer 3

Maybe the problem is that json.dumps puts " and in the json you put in the url there are no "s. For example:

data = {'temperature':'24.3'}
print json.dumps(data)

prints:

{"temperature": "24.3"}

and not:

{temperature: 24.3}

like you put in your url.

One way of solving this (which is trouble prone) is to do:

json.dumps(data).replace('"', '')