Golang HTTP client. Do (req) cannot be used two times

Initializing the client, and the request unexpectedly cannot be called the second time, odd eight strange.

Not much to read the source, but know where the problem.

First the code looks like this:

resp, err := client.Do(req)resp, err := client.Do(req)

Originally thought about a period of time to refresh the data, to see what changes in the data, so I think can be reused req, but did not expect the error:

: http: ContentLength=15 with Body length 0

What is this for? In-depth investigation, first look at the req long what kind of

req, err = http.NewRequest("POST", "some url", strings.NewReader("articleId="+articleId))

The third parameter is the body,
Req. Body length is like this:

type Reader struct {    s        string    i        int64 // current reading index    prevRune int   // index of previous rune; or < 0}

See this suddenly understand, client. The Do method reads the body data according to the I value in reader, that is, call its Read method, I value will change, of course, after reading, I value will become contentlength. Then the next time the use of the time, because no data can be read, resulting in the error Body length 0 .

How should the situation be solved?

。。。

New reader ...