为了保护应用程序不崩溃，尝试使用异常处理的替代方案。

huangapple
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英文:

Try exception alternative for protect not crash application

问题

我有一个用于抓取URL的Go应用程序。问题是它有时会崩溃并返回以下错误：

  1. panic: runtime error: slice bounds out of range
  2. goroutine 1 [running]:
  3. main.dom6(0x187d4140, 0x8, 0x187d4179, 0x5, 0x187c0800, 0x6, 0x13, 0x83007cb)
  4.         /root/sswork.go:326 +0x6b
  5. main.sub(0x187d4140, 0x8, 0x84464e0, 0x6, 0x6, 0x187d4140, 0x8, 0x187d4179, 0x5, 0x187c0800, ...)
  6.         /root/sswork.go:298 +0xb3
  7. main.main()
  8.         /root/sswork.go:615 +0xccb

在第298行是这个函数：

  1. 294: // try our list of substitutions, if one works return it
  2. 295: func sub(str string, xs []subs, u string, p string, h string) string {
  3. 296:	for _, x := range xs {
  4. 297:		if strings.Contains(str, x.pattern) {
  5. 298:			return strings.Replace(str, x.pattern, x.fn(u, p, h), 1)
  6. 299:		}
  7. 300:	}
  8. 301:	return str
  9. 302:}

如何解决这个问题，使应用程序不再崩溃？

  1. 324: // the first 6 characters of the above
  2. 325: func dom6(u string, p string, d string) string {
  3. 326:	return domfull(u, p, d)[0:6]
  4. 327: }
英文:

I have a Go application for scrape URLs. The problem is it sometimes crashes and returns this error:

  1. panic: runtime error: slice bounds out of range
  2. goroutine 1 [running]:
  3. main.dom6(0x187d4140, 0x8, 0x187d4179, 0x5, 0x187c0800, 0x6, 0x13, 0x83007cb)
  4.         /root/sswork.go:326 +0x6b
  5. main.sub(0x187d4140, 0x8, 0x84464e0, 0x6, 0x6, 0x187d4140, 0x8, 0x187d4179, 0x5, 0x187c0800, ...)
  6.         /root/sswork.go:298 +0xb3
  7. main.main()
  8.         /root/sswork.go:615 +0xccb

on line 298 is this function :

  1. 294: // try our list of substitutions, if one works return it
  2. 295: func sub(str string, xs []subs, u string, p string, h string) string {
  3. 296:	for _, x := range xs {
  4. 297:		if strings.Contains(str, x.pattern) {
  5. 298:			return strings.Replace(str, x.pattern, x.fn(u, p, h), 1)
  6. 299:		}
  7. 300:	}
  8. 301:	return str
  9. 302:}

How can I solve my problem so it doesn't crash the application any more?

  1. 324: // the first 6 characters of the above
  2. 325: func dom6(u string, p string, d string) string {
  3. 326:	return domfull(u, p, d)[0:6]
  4. 327: }

答案1

得分: 2

错误出现在第326行，而不是第298行。为了避免这样的恐慌，应在尝试对切片、数组或字符串进行索引或切片之前进行手动索引检查。

您指出第298行的代码如下：

  1. // 上述代码的前6个字符
  2. func dom6(u string, p string, d string) string {
  3.     return domfull(u, p, d)[0:6]
  4. }

在尝试对其进行切片之前，请检查domfull()返回的string的长度，例如：

  1. func dom6(u string, p string, d string) string {
  2.     df := domfull(u, p, d)
  3.     if len(df) < 6 {
  4.         return df
  5.     }
  6.     return df[:6]
  7. }
英文:

The error is at line 326, not 298. And to avoid such panics, perform manual index check before attempting to index or slice a slice, array or string.

You indicated that the code at line 298 is:

  1. // the first 6 characters of the above
  2. func dom6(u string, p string, d string) string {
  3.     return domfull(u, p, d)[0:6]
  4. }

Check the length of the string returned by domfull() before attempting to slice it, e.g.:

  1. func dom6(u string, p string, d string) string {
  2.     df := domfull(u, p, d)
  3.     if len(df) &lt; 6 {
  4.         return df
  5.     }
  6.     return df[:6]
  7. }

huangapple
  • 本文由 发表于 2017年9月8日 18:25:27
  • 转载请务必保留本文链接：https://go.coder-hub.com/46114325.html
  • go
  • runtime-error
  • string
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