（六）、获取Keystone token的三种方式

让我们粗略看一下，三种从Keystone获得token的方式。在尝试这三种方式之前，你得确保已经装好Keystone终端。如果还没有装好，可以看grizzly安装版本的Keystone 安装部分。

Note:这些呼叫都将请求的是Keystone v2版本。 

假定你已经安装好，并且Keystone已经跑起来了：）。然后接下来我们首先要做的便是，发一个简单的cURL发送请求：

$ curl -d '{"auth": {"tenantName": "demo", "passwordCredentials": {"username": "demo", "password": "password"}}}' -H "Content-type: application/json" http://localhost:5000/v2.0/tokens

其中的tenantName 是作用域名。假使你省略了这个名字，将会获得一个无作用域的token.

当请求发送完毕，主机会返回一个JSON字符串类似如下（你的可能不一样）：

{
    "access": {
        "token": {
            "issued_at": "2014-02-10T00:40:20.909222",
            "expires": "2014-02-11T00:40:20Z",
            "id": "MIIDjwYJKoZIhvcNAQcCoIIDgDC",
            "tenant": {
                "description": null,
                "enabled": true,
                "id": "8cdca733159c4bf6a622b9bb25a73ad6",
                "name": "demo"
            }
        },
        "serviceCatalog": [],
        "user": {
            "username": "demo",
            "roles_links": [],
            "id": "d5cf3796f7c04a468b5282555110ba5d",
            "roles": [
                {
                    "name": "member"
                }
            ],
            "name": "demo"
        },
        "metadata": {
            "is_admin": 0,
            "roles": [
                "a790ff829b0e4bc29d5ca4bbc58d48f1"
            ]
        }
    }
}

现在假定你不想继续用python-keystoneclient，而是调用库函数urllib2的Python项目中获得作用域token，然后你可以这样做:

from __future__ import print_function

import urllib2
import json


if __name__ = = "__main__" :
    json_payload = {
        "auth" : {
            "tenantName" : "demo" ,
            "passwordCredentials" : {
                "username" : "demo" ,
                "password" : "password"
            }
        }
    }

    headers = { 'content-type' : 'application/json' , 'accept' : 'application/json' }

    request = urllib2.Request(url = 'http://localhost:5000/v2.0/tokens' ,
                              data = json.dumps(json_payload),
                              headers = headers)

    keystone_response = urllib2.urlopen(request)

    returned_data = json.loads(keystone_response.read())

    if keystone_response.getcode() = = 200 :
        print (returned_data)
    else :
        print ( 'Something went wrong!' )

 最后一种方式是调用Requests 库，例子如下：

from __future__ import print_function

import requests
import json


if __name__ = = "__main__" :
    json_payload = {
        "auth" : {
            "tenantName" : "demo" ,
            "passwordCredentials" : {
                "username" : "demo" ,
                "password" : "password"
            }
        }
    }

    headers = { 'content-type' : 'application/json' , 'accept' : 'application/json' }

    response = requests.post(url = 'http://localhost:5000/v2.0/tokens' ,
                             data = json.dumps(json_payload),
                             headers = headers)

    if response.status_code = = requests.codes.ok:
        print (response.json())
    else :
        print ( 'Something went wrong!' )

和urllib2的那种方式似乎区别不大，就是少了几句代码，不过似乎更加清晰了。

当然最好还是用 Python Keystone Client 这种方式，比较容易上手，而且简单明了。