跨域API

跨域API

简单跨域请求
只需要简单的设置允许跨域就可以了

def set_default_headers(self):
        self.set_header('Access-Control-Allow-Origin', '*')

满足下面条件的就是简单请求，否则就不是

Simple requests
 
A simple cross-site request is one that meets all the following conditions:
 
The only allowed methods are:
GET
HEAD
POST
Apart from the headers set automatically by the user agent (e.g. Connection, User-Agent, etc.), the only headers which are allowed to be manually set are:
Accept
Accept-Language
Content-Language
Content-Type
The only allowed values for the Content-Type header are:
application/x-www-form-urlencoded
multipart/form-data
text/plain

复杂跨域请求
所有的非简单请求，比如content-Type：application/json的POST请求，CORS详解
复杂的跨域请求，浏览器会先发起一个OPTIONS类型的验证请求，检查服务端是否允许即将发起的真正的请求类型(主要是Methods和headers)，如果允许的话，就需要像下面这样设置设置对应的rul

def set_default_headers(self):
        self.set_header('Access-Control-Allow-Origin', '*')
        self.set_header('Access-Control-Allow-Methods', 'POST, GET, OPTIONS')
        self.set_header('Access-Control-Max-Age', 86400) #24 hours
        self.set_header('Access-Control-Allow-Headers', '*')
        #self.set_header('Content-type', 'application/json')

服务端可以对不同的url配置不同的跨域信息，这也是网站安全的基本配置

复杂请求的过程

发起的OPTIONS请求：

OPTIONS /resources/post-here/ HTTP/1.1
Host: bar.other
User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1b3pre) Gecko/20081130 Minefield/3.1b3pre
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Connection: keep-alive
Origin: http://foo.example
Access-Control-Request-Method: POST
Access-Control-Request-Headers: X-PINGOTHER, Content-Type

服务端对OPTIONS请求的响应：

HTTP/1.1 200 OK
Date: Mon, 01 Dec 2008 01:15:39 GMT
Server: Apache/2.0.61 (Unix)
Access-Control-Allow-Origin: http://foo.example
Access-Control-Allow-Methods: POST, GET, OPTIONS
Access-Control-Allow-Headers: X-PINGOTHER, Content-Type
Access-Control-Max-Age: 86400
Vary: Accept-Encoding, Origin
Content-Encoding: gzip
Content-Length: 0
Keep-Alive: timeout=2, max=100
Connection: Keep-Alive
Content-Type: text/plain

验证成功后发起真正的请求：

POST /resources/post-here/ HTTP/1.1
Host: bar.other
User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1b3pre) Gecko/20081130 Minefield/3.1b3pre
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Connection: keep-alive
X-PINGOTHER: pingpong
Content-Type: text/xml; charset=UTF-8
Referer: http://foo.example/examples/preflightInvocation.html
Content-Length: 55
Origin: http://foo.example
Pragma: no-cache
Cache-Control: no-cache

<?xml version="1.0"?><person><name>Arun</name></person>


HTTP/1.1 200 OK
Date: Mon, 01 Dec 2008 01:15:40 GMT
Server: Apache/2.0.61 (Unix)
Access-Control-Allow-Origin: http://foo.example
Vary: Accept-Encoding, Origin
Content-Encoding: gzip
Content-Length: 235
Keep-Alive: timeout=2, max=99
Connection: Keep-Alive
Content-Type: text/plain

[Some GZIP'd payload]

参考
http://www.oschina.net/question/1014827_115277?sort=time
http://blog.csdn.net/wangjun5159/article/details/49096445
https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS#Preflighted_requests