英文:
In Golang, transformation from int64 to string and then slice doesn't work
问题
我有一个客户端代码，从API接收到一个经过gzip压缩的响应：
client := &http.Client{}
response, _ := client.Do(r)
// 检查服务器是否实际发送了压缩数据
var reader io.ReadCloser
switch response.Header.Get("Content-Encoding") {
case "gzip":
reader, err := gzip.NewReader(response.Body)
if err != nil {
log.Fatal(err)
}
defer reader.Close()
default:
reader = response.Body
}
token, err := io.Copy(os.Stdout, reader)
if err != nil {
log.Fatal(err)
}
cadenita := strconv.FormatInt(token, 10)
fmt.Println(cadenita)
cadena := "code=b2cc1793-cb7a-ea8d-3c82-766557"
fmt.Println(cadena[5:])
这段代码显示了以下内容：
但是，如果我直接在cadenita上使用[5:]进行切片，尽管它也是一个字符串，我会遇到这个错误。
我想要能够在转换为字符串的token（int64）上进行切片和正则表达式操作。我该如何做到这一点？
英文:
I've have this code on a client that receives a gzipped response from an API :
client := &http.Client{}
response, _ := client.Do(r)
// Check that the server actual sent compressed data
var reader io.ReadCloser
switch response.Header.Get("Content-Encoding") {
case "gzip":
reader, err := gzip.NewReader(response.Body)
if err != nil {
log.Fatal(err)
}
defer reader.Close()
default:
reader = response.Body
}
token, err := io.Copy(os.Stdout, reader)
if err != nil {
log.Fatal(err)
}
cadenita := strconv.FormatInt(token, 10)
fmt.Println(cadenita)
cadena := "code=b2cc1793-cb7a-ea8d-3c82-766557"
fmt.Println(cadena[5:])
This code shows :
But, if I use [5:] directly on cadenita, although it's also a string, I have this error.
I want to be able to slice and regex on the token(int64) transformed in a string. How can I do so ?
答案1
得分: 2
io.Copy返回复制的字节数，所以这就是你的token变量中的值，所以在你的示例中大约是40。FormatInt将其转换为字符串"40"，该字符串只有2个字符，所以当你请求从"40"的第5个字符开始的子字符串时，会出现错误。
你是想获取token中的实际响应数据吗？如果是的话，你需要将其复制到一个缓冲区中，例如：
buff := bytes.Buffer{}
_, err := io.Copy(&buff, reader)
if err != nil {
log.Fatal(err)
}
fmt.Println(buff.String()[5:])
英文:
io.Copy returns the number of bytes copied, so that's the value thats in your token variable, so somewhere in the area of 40 for your example. FormatInt converts that to a string "40" which only has 2 chars, so it'll error as you see when you ask for the substring starting at char 5 of "40".
Are you trying to get the actual response data in token? if so you'll need to copy it into a buffer, e.g.
buff := bytes.Buffer{}
_, err := io.Copy(&buff, reader)
if err != nil {
log.Fatal(err)
}
fmt.Println(buff.String()[5:])
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