使用python向RESTful API发出请求

I have a RESTful API that I have exposed using an implementation of Elasticsearch on an EC2 instance to index a corpus of content. I can query the search by running the following from my terminal (MacOSX):

curl -XGET 'http://ES_search_demo.com/document/record/_search?pretty=true' -d '{
  "query": {
    "bool": {
      "must": [
        {
          "text": {
            "record.document": "SOME_JOURNAL"
          }
        },
        {
          "text": {
            "record.articleTitle": "farmers"
          }
        }
      ],
      "must_not": [],
      "should": []
    }
  },
  "from": 0,
  "size": 50,
  "sort": [],
  "facets": {}
}'

How do I turn above into a API request using python/requests or python/urllib2 (not sure which one to go for – have been using urllib2, but hear that requests is better…)? Do I pass as a header or otherwise?

Using requests:

import requests
url = 'http://ES_search_demo.com/document/record/_search?pretty=true'
data = '''{
  "query": {
    "bool": {
      "must": [
        {
          "text": {
            "record.document": "SOME_JOURNAL"
          }
        },
        {
          "text": {
            "record.articleTitle": "farmers"
          }
        }
      ],
      "must_not": [],
      "should": []
    }
  },
  "from": 0,
  "size": 50,
  "sort": [],
  "facets": {}
}'''
response = requests.post(url, data=data)

Depending on what kind of response your API returns, you will then probably want to look at response.text or response.json() (or possibly inspect response.status_code first). See the quickstart docs here, especially this section.

Using requests and json makes it simple.

1. Call the API
2. Assuming the API returns a JSON, parse the JSON object into a Python dict using json.loads function
3. Loop through the dict to extract information.

Requests module provides you useful function to loop for success and failure.

if(Response.ok): will help help you determine if your API call is successful (Response code – 200)

Response.raise_for_status() will help you fetch the http code that is returned from the API.

Below is a sample code for making such API calls. Also can be found in github. The code assumes that the API makes use of digest authentication. You can either skip this or use other appropriate authentication modules to authenticate the client invoking the API.

#Python 2.7.6
#RestfulClient.py

import requests
from requests.auth import HTTPDigestAuth
import json

# Replace with the correct URL
url = "http://api_url"

# It is a good practice not to hardcode the credentials. So ask the user to enter credentials at runtime
myResponse = requests.get(url,auth=HTTPDigestAuth(raw_input("username: "), raw_input("Password: ")), verify=True)
#print (myResponse.status_code)

# For successful API call, response code will be 200 (OK)
if(myResponse.ok):

    # Loading the response data into a dict variable
    # json.loads takes in only binary or string variables so using content to fetch binary content
    # Loads (Load String) takes a Json file and converts into python data structure (dict or list, depending on JSON)
    jData = json.loads(myResponse.content)

    print("The response contains {0} properties".format(len(jData)))
    print("\n")
    for key in jData:
        print key + " : " + jData[key]
else:
  # If response code is not ok (200), print the resulting http error code with description
    myResponse.raise_for_status()

So you want to pass data in body of a GET request, better would be to do it in POST call. You can achieve this by using both Requests.

Raw Request

GET http://ES_search_demo.com/document/record/_search?pretty=true HTTP/1.1
Host: ES_search_demo.com
Content-Length: 183
User-Agent: python-requests/2.9.0
Connection: keep-alive
Accept: */*
Accept-Encoding: gzip, deflate

{
  "query": {
    "bool": {
      "must": [
        {
          "text": {
            "record.document": "SOME_JOURNAL"
          }
        },
        {
          "text": {
            "record.articleTitle": "farmers"
          }
        }
      ],
      "must_not": [],
      "should": []
    }
  },
  "from": 0,
  "size": 50,
  "sort": [],
  "facets": {}
}

Sample call with Requests

import requests

def consumeGETRequestSync():
data = '{
  "query": {
    "bool": {
      "must": [
        {
          "text": {
            "record.document": "SOME_JOURNAL"
          }
        },
        {
          "text": {
            "record.articleTitle": "farmers"
          }
        }
      ],
      "must_not": [],
      "should": []
    }
  },
  "from": 0,
  "size": 50,
  "sort": [],
  "facets": {}
}'
url = 'http://ES_search_demo.com/document/record/_search?pretty=true'
headers = {"Accept": "application/json"}
# call get service with headers and params
response = requests.get(url,data = data)
print "code:"+ str(response.status_code)
print "******************"
print "headers:"+ str(response.headers)
print "******************"
print "content:"+ str(response.text)

consumeGETRequestSync()

Below is the program to execute the rest api in python-

import requests
url = 'https://url'
data = '{  "platform": {    "login": {      "userName": "name",      "password": "pwd"    }  } }'
response = requests.post(url, data=data,headers={"Content-Type": "application/json"})
print(response)
sid=response.json()['platform']['login']['sessionId']   //to extract the detail from response
print(response.text)
print(sid)