英文:
How to get the type of error to use in error handling
问题
如果你这样做：
_, err := http.Get("google.com")if err != nil {log.Fatal(err)}
你会得到以下输出：
2021/08/05 15:42:18 Get "google.com": unsupported protocol scheme ""
我想知道如何获取错误的类型，这样我就可以像这样处理错误：
if errors.Is(err, "unsupported protocol scheme") {// 在 URL 字符串中添加协议方案}
我尝试了 fmt.Printf("%#v", err)，得到的结果是：
&url.Error{Op:"Get", URL:"google.com", Err:(*errors.errorString)(0xc000098c40)}
fmt.Printf("%T") 得到的结果是：
*url.Error
编辑：如果你给我点踩，我真的希望你能留下评论，告诉我你的想法。
英文:
If you do this:
_, err := http.Get("google.com")if err != nil {log.Fatal(err)}
you get the output:
2021/08/05 15:42:18 Get "google.com": unsupported protocol scheme ""
I'm wondering how do I get the type of error, so I can handle the error like so:
if errors.Is(err, "unsupported protocol scheme") {//add protocol scheme to url string}
I've tried fmt.Printf("%#v", err), which gives:
&url.Error{Op:"Get", URL:"google.com", Err:(*errors.errorString)(0xc000098c40)}
fmt.Printf("%T") gives:
*url.Error
Edit: If you're downvoting, I'd really appreciate a comment with your thoughts.
答案1
得分: 3
var e *url.Errorif errors.As(err, &e) && strings.HasPrefix(e.Err.Error(), "unsupported protocol scheme") {//在URL字符串中添加协议方案}
请注意，与非标准化字符串进行比较不应被视为具有未来性。例如，如果Go的未来版本决定更改该错误消息的措辞，您的代码将会出错。
尽管Go承诺在不同版本之间保持兼容性，但我认为这个承诺不包括字符串内容。
英文:
var e *url.Errorif errors.As(err, &e) && strings.HasPrefix(e.Err.Error(), "unsupported protocol scheme") {//add protocol scheme to url string}
https://play.golang.org/p/VKpMfrBp_EF
Note that comparison against non-standardized strings should not be considered future-proof. For example if a future version of Go decides to change the wording of that error message your code will break.
Although Go does promise compatibility across versions, I don't think that that promise extends to string content.
答案2
得分: 0
你可以使用err.Error()来返回字符串。
并且检查它是否包含特定的键，类似于这样：
if err = db.Ping(); err != nil {switch {case strings.Contains(err.Error(), "connection refused"):// 处理连接被拒绝的情况。例如：cmd := exec.Command("sudo", "service", "mariadb", "start")_ = cmd.Run()default:log.Println("未知类型的错误", err)}}
在你的情况下，你可以尝试类似这样的代码：
err := http.Get(url)if strings.Contains(err.Error(), "unsupported protocol scheme") {// 将协议方案添加到url字符串中}
英文:
you can use err.Error() to return string.
and check if it contiane a spicifice keys, something like this:
if err = db.Ping(); err != nil {switch {case strings.Contains(err.Error(), "connection refused"):// handle connection refused. for example:cmd := exec.Command("sudo", "service", "mariadb", "start")_ = cmd.Run()default:log.Println("unknown kind of this error", err)}}
in your case you can try somthing like:
err := http.Get(url)if strings.Contains(err.Error(), "unsupported protocol scheme") {//add protocol scheme to url string}
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