以下是我提取 GET 参数的 go 程序。 (网址:/mysql?hostname=example.com)
package main
import (
"net/http"
"fmt"
//"encoding/json"
//"html"
"github.com/kr/pretty"
);
func main(){
http.HandleFunc("/", foo)
http.ListenAndServe(":80", nil)
}
func foo(w http.ResponseWriter, r * http.Request){
w.Header().Set("Server","A Go WebServer")
w.Header().Set("Content-Type", "text/html")
hostname := r.URL.Query()["hostname"]
//w.Write([]byte(hostname[0]))
fmt.Printf("%# v", pretty.Formatter(hostname[0]))
w.Write([]byte(hostname))
}
控制台上显示错误。
"example.com"2014/09/01 02:57:22 http: panic serving 172.17.92.14:49411: runtime error: index out of range
/usr/lib/go/src/pkg/net/http/server.go:576 (0x42dc41)
_func_003: buf.Write(debug.Stack())
/home/michael/DPKG/golang/src/pkg/runtime/proc.c:1443 (0x40f8b5)
/home/michael/DPKG/golang/src/pkg/runtime/runtime.c:128 (0x410381)
/home/michael/DPKG/golang/src/pkg/runtime/runtime.c:85 (0x410228)
/root/go/src/api/main.go:34 (0x400d77)
foo: fmt.Printf("%# v", pretty.Formatter(hostname[0]))
/usr/lib/go/src/pkg/net/http/server.go:690 (0x421bed)
HandlerFunc.ServeHTTP: f(w, r)
/usr/lib/go/src/pkg/net/http/server.go:926 (0x422a6f)
(*ServeMux).ServeHTTP: mux.handler(r).ServeHTTP(w, r)
/usr/lib/go/src/pkg/net/http/server.go:656 (0x421a00)
(*conn).serve: handler.ServeHTTP(w, w.req)
/home/michael/DPKG/golang/src/pkg/runtime/proc.c:271 (0x40d9bb)
2014/09/01 02:57:22 http: panic serving 172.17.92.14:49412: runtime error: index out of range
/usr/lib/go/src/pkg/net/http/server.go:576 (0x42dc41)
_func_003: buf.Write(debug.Stack())
/home/michael/DPKG/golang/src/pkg/runtime/proc.c:1443 (0x40f8b5)
/home/michael/DPKG/golang/src/pkg/runtime/runtime.c:128 (0x410381)
/home/michael/DPKG/golang/src/pkg/runtime/runtime.c:85 (0x410228)
/root/go/src/api/main.go:34 (0x400d77)
foo: fmt.Printf("%# v", pretty.Formatter(hostname[0]))
/usr/lib/go/src/pkg/net/http/server.go:690 (0x421bed)
HandlerFunc.ServeHTTP: f(w, r)
/usr/lib/go/src/pkg/net/http/server.go:926 (0x422a6f)
(*ServeMux).ServeHTTP: mux.handler(r).ServeHTTP(w, r)
/usr/lib/go/src/pkg/net/http/server.go:656 (0x421a00)
(*conn).serve: handler.ServeHTTP(w, w.req)
/home/michael/DPKG/golang/src/pkg/runtime/proc.c:271 (0x40d9bb)
2014/09/01 02:57:22 http: panic serving 172.17.92.14:49413: runtime error: index out of range
/usr/lib/go/src/pkg/net/http/server.go:576 (0x42dc41)
_func_003: buf.Write(debug.Stack())
/home/michael/DPKG/golang/src/pkg/runtime/proc.c:1443 (0x40f8b5)
/home/michael/DPKG/golang/src/pkg/runtime/runtime.c:128 (0x410381)
/home/michael/DPKG/golang/src/pkg/runtime/runtime.c:85 (0x410228)
/root/go/src/api/main.go:34 (0x400d77)
foo: fmt.Printf("%# v", pretty.Formatter(hostname[0]))
/usr/lib/go/src/pkg/net/http/server.go:690 (0x421bed)
HandlerFunc.ServeHTTP: f(w, r)
/usr/lib/go/src/pkg/net/http/server.go:926 (0x422a6f)
(*ServeMux).ServeHTTP: mux.handler(r).ServeHTTP(w, r)
/usr/lib/go/src/pkg/net/http/server.go:656 (0x421a00)
(*conn).serve: handler.ServeHTTP(w, w.req)
/home/michael/DPKG/golang/src/pkg/runtime/proc.c:271 (0x40d9bb)
我无法确定主机名变量的数据类型。我应该把它当作一个字符串。
当我尝试写入 http 响应编写器时
w.Write([]byte(hostname))
显示以下构建错误
go/src/api/main.go:38: cannot convert hostname (type []string) to type []byte
如果我把它当作一个字符串数组构建成功但是有运行时错误
newhost := hostname[0];
w.Write([]byte(newhost))
错误:
2014/09/01 04:42:40 http: panic serving 172.17.92.14:50404: runtime error: index out of range
/usr/lib/go/src/pkg/net/http/server.go:576 (0x42db27)
_func_003: buf.Write(debug.Stack())
/home/michael/DPKG/golang/src/pkg/runtime/proc.c:1443 (0x40f79b)
/home/michael/DPKG/golang/src/pkg/runtime/runtime.c:128 (0x410267)
/home/michael/DPKG/golang/src/pkg/runtime/runtime.c:85 (0x41010e)
/root/go/src/api/main.go:38 (0x400d63)
foo: newhost := hostname[0];
/usr/lib/go/src/pkg/net/http/server.go:690 (0x421ad3)
HandlerFunc.ServeHTTP: f(w, r)
/usr/lib/go/src/pkg/net/http/server.go:926 (0x422955)
(*ServeMux).ServeHTTP: mux.handler(r).ServeHTTP(w, r)
/usr/lib/go/src/pkg/net/http/server.go:656 (0x4218e6)
(*conn).serve: handler.ServeHTTP(w, w.req)
/home/michael/DPKG/golang/src/pkg/runtime/proc.c:271 (0x40d8a1)
2014/09/01 04:42:40 http: panic serving 172.17.92.14:50405: runtime error: index out of range
/usr/lib/go/src/pkg/net/http/server.go:576 (0x42db27)
_func_003: buf.Write(debug.Stack())
/home/michael/DPKG/golang/src/pkg/runtime/proc.c:1443 (0x40f79b)
/home/michael/DPKG/golang/src/pkg/runtime/runtime.c:128 (0x410267)
/home/michael/DPKG/golang/src/pkg/runtime/runtime.c:85 (0x41010e)
/root/go/src/api/main.go:38 (0x400d63)
foo: newhost := hostname[0];
/usr/lib/go/src/pkg/net/http/server.go:690 (0x421ad3)
HandlerFunc.ServeHTTP: f(w, r)
/usr/lib/go/src/pkg/net/http/server.go:926 (0x422955)
(*ServeMux).ServeHTTP: mux.handler(r).ServeHTTP(w, r)
/usr/lib/go/src/pkg/net/http/server.go:656 (0x4218e6)
(*conn).serve: handler.ServeHTTP(w, w.req)
/home/michael/DPKG/golang/src/pkg/runtime/proc.c:271 (0x40d8a1)
2014/09/01 04:42:40 http: panic serving 172.17.92.14:50406: runtime error: index out of range
/usr/lib/go/src/pkg/net/http/server.go:576 (0x42db27)
_func_003: buf.Write(debug.Stack())
/home/michael/DPKG/golang/src/pkg/runtime/proc.c:1443 (0x40f79b)
/home/michael/DPKG/golang/src/pkg/runtime/runtime.c:128 (0x410267)
/home/michael/DPKG/golang/src/pkg/runtime/runtime.c:85 (0x41010e)
/root/go/src/api/main.go:38 (0x400d63)
foo: newhost := hostname[0];
/usr/lib/go/src/pkg/net/http/server.go:690 (0x421ad3)
HandlerFunc.ServeHTTP: f(w, r)
/usr/lib/go/src/pkg/net/http/server.go:926 (0x422955)
(*ServeMux).ServeHTTP: mux.handler(r).ServeHTTP(w, r)
/usr/lib/go/src/pkg/net/http/server.go:656 (0x4218e6)
(*conn).serve: handler.ServeHTTP(w, w.req)
/home/michael/DPKG/golang/src/pkg/runtime/proc.c:271 (0x40d8a1)
我还按照@VonC 的建议检查了新主机的长度,它给出了预期的结果。
fmt.Print("\n")
fmt.Println((len(newhost)))
控制台输出
"example.com"
11
2014/09/01 05:05:15 http: panic serving 172.17.92.14:50779: runtime error: index out of range
/usr/lib/go/src/pkg/net/http/server.go:576 (0x42dd33)
最佳答案
您需要使用 url/Values.Get
,如果未设置值,它将返回空字符串:
hostname := r.URL.Query().Get("hostname")
if len(hostname) != 0 {
io.WriteString(w, hostname) // or
w.Write([]byte(hostname))
}
//编辑
让我们一步一步来:
go/src/api/main.go:38: 无法将主机名(类型 []string)转换为类型 []byte
:
req.URL.Query["hostname"]
,返回一个不能直接转换成[]的字符串 slice (
,只有[]string
) bytestring
可以这样转换。
第一个运行时错误:索引超出范围
:
- 您尝试使用
hostname[0]
而不检查 slice 中有多少元素,因此在这种情况下没有任何元素。
最后一个 runtime error: index out of range
很奇怪,我不知道你为什么得到它,一定是你在代码中更改的其他内容。
关于web-services - 在 golang 中访问 GET 参数 net/http 的问题,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/25600521/