net/http

client.go

结构: Client
变量: DefaultClient
接口: RoundTripper
函数: //TODO

Client指的是http客户端. 它的默认值是DefaultClient. 其中, DefaultClient以DefaultTransport作为传输层的.

典型的客户端传输层, 其内部具有缓存的TCP连接, 所以客户端应该优先重用, 而不是重新创建. 使用goroutines可以实现安全的客户端并发请求.

Client是比RoundTripper(Transport只是RounderTripper的一个实现)更高一级的存在, 用来处理重定向、cookie等HTTP细节.

• when forwarding sensitive headers like “Authorization”, “WWW-Authenticate”, and “Cookie” to untrusted targets. These headers will be ignored when following a redirect to a domain that is not a subdomain match or exact match of the initial domain. For example, a redirect from “foo.com” to either “foo.com” or “sub.foo.com” will forward the sensitive headers, but a redirect to “bar.com” will not.

• when forwarding the “Cookie” header with a non-nil cookie Jar. Since each redirect may mutate the state of the cookie jar, a redirect may possibly alter a cookie set in the initial request. When forwarding the “Cookie” header, any mutated cookies will be omitted, with the expectation that the Jar will insert those mutated cookies with the updated values (assuming the origin matches). If Jar is nil, the initial cookies are forwarded without change.