Access WebAPI with Python and register / acquire IoT data (dweet.io, Requests, HTTPie)

Let's use WebAPI to use dweet.io, an IoT data messaging service. The image below is the Vegetable Condition Monitoring Dashboard created using the services of Raspberry Pi and dweet.io. (Details will be introduced in another article)

Method 1. Access the Web API with the Terminal command

Even if you let python do it at the end, it is convenient if you can check the operation quickly with terminal.

Install HTTPie

mac

$ brew install httpie

It is an iron plate library with 30,000 Github Stars! The highlights make the Response header very easy to see.

Once installed, you can use HTTP methods with the http command. (Default is GET method)

Data registration

dweet.io can easily register data by throwing a query of ? Key = value to the URL ofhttps://dweet.io/dweet/for/ <id>. (You can also register JSON data using the POST method (described later))

# -v Optional request_header can also be output
$ http https://dweet.io/dweet/for/my-thing-name?hello=world

response by httpie_header output

HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Connection: keep-alive
Content-Encoding: gzip
Content-Type: application/json
Date: Mon, 08 May 2017 03:13:38 GMT
Transfer-Encoding: chunked

{
    "by": "dweeting",
    "the": "dweet",
    "this": "succeeded",
    "with": {
        "content": {
            "hello": "world"
        },
        "created": "2017-05-08T03:13:38.230Z",
        "thing": "my-thing-name",
        "transaction": "54f19ae4-3428-4ea3-8275-1a77d49a11a0"
    }
}

Data acquisition

dweet.io can get the data in JSON format by accessing the URL of https://dweet.io/get/latest/dweet/for/ <id> with the GET method.

$ http https://dweet.io/get/latest/dweet/for/my-thing-name

response by httpie_header output 2

HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Connection: keep-alive
Content-Encoding: gzip
Content-Type: application/json
Date: Mon, 08 May 2017 03:13:55 GMT
Transfer-Encoding: chunked

{
    "by": "getting",
    "the": "dweets",
    "this": "succeeded",
    "with": [
        {
            "content": {
                "hello": "world"
            },
            "created": "2017-05-08T03:13:38.230Z",
            "thing": "my-thing-name"
        }
    ]
}

Method 2. Access the Web API from Python

Install Requests

$ pip install requests

Requests is a human-friendly HTTP library for Python with a very intuitive API. This is also a library of 25000 and iron plates by GitHub Stars.

The usage of the Requests library is as follows. Official quickstart is a very cohesive document and is recommended.

import requests

#get
r = requests.get('url')
#get:With query
payload = {'key1': 'value1', 'key2': 'value2'}
r = requests.get('url', params=payload)

#post
r = requests.post('url', data = {'key':'value'})

#cookies
r = requests.get('url')
cookie = r.cookies['cookie_name']
r = requests.get('url', cookies=cookie)

#response
print(r.url) 
print(r.status_code)
print(r.headers)
print(r.text)
print(r.content)
print(r.json())

What happens if the url is wrong:

• site does not exist: exit with an exception
• page does not exist: Some object is returned (status_code = 404, etc.)

Data registration / acquisition

Data registration / acquisition to dweet.io using Requests can be done as follows

import requests
import pprint
import time

#Data registration: post
for i in range(10):
  r = requests.post('https://dweet.io/dweet/for/iot-data', data = {'temp':'23', 'humid':'40'})
  time.sleep(1)

#Data acquisition: get
r = requests.get("https://dweet.io/get/latest/dweet/for/iot-data")
pprint.pprint(r.json())

terminal output result

{u'by': u'getting',
 u'the': u'dweets',
 u'this': u'succeeded',
 u'with': [{u'content': {u'humid': 40, u'temp': 23},
            u'created': u'2017-05-08T04:04:18.887Z',
            u'thing': u'iot-data'}]}

Reference: http://qiita.com/ogawatachi/items/d178bce8a9e60b5d459b