template.Execute():无效的内存地址或无指针取消引用

Question

我正在尝试使用自定义分隔符的Go html /模板.

但是,我可以解析并执行我的"index.html"文件,每当我尝试更改模板分隔符时,我面临以下错误:

runtime error: invalid memory address or nil pointer dereference goroutine

这是我的代码:

package main

import (
        "html/template"
        "net/http"
)

var sherrifTmpl = template.New("test").Delims("{[{", "}]}")

func serveHome(w http.ResponseWriter, r *http.Request) {
        template.Must(sherrifTmpl.ParseFiles("index.html")).Execute(w, r)
}

如果我尝试以下任何一项:

package main

import (
        "html/template"
        "net/http"
)

func serveHome(w http.ResponseWriter, r *http.Request) {
        template.Must(template.ParseFiles("index.html")).Execute(w, r)
}

要么:

package main

import (
        "html/template"
        "net/http"
)

var sherrifTmpl = template.New("test").Delims("{[{", "}]}")

func serveHome(w http.ResponseWriter, r *http.Request) {
        template.Must(sherrifTmpl.ParseFiles("{[{.Host}]}")).Execute(w, r)
}

一切正常.我甚至试图捕获ParseFiles错误.但仍然没有运气:

package main

import (
        "html/template"
        "net/http"
)

var sherrifTmpl = template.New("test").Delims("{[{", "}]}")

func serveHome(w http.ResponseWriter, r *http.Request) {
        homeTmpl, err := sherrifTmpl.ParseFiles("index.html")
        if err != nil {
            panic(err)
        }
        homeTmpl.Execute(w, r)
}

我看不出我做错了什么.如果你们中的任何人能帮助我解决这个问题,我将不胜感激.

更新1:

这是恐慌:

2015/04/13 17:43:35 http: panic serving 127.0.0.1:56634: runtime error: invalid memory address or nil pointer dereference
goroutine 5 [running]:
net/http.func·011()
    /usr/local/go/src/net/http/server.go:1130 +0xbb
html/template.(*Template).escape(0xc20803ad80, 0x0, 0x0)
    /usr/local/go/src/html/template/template.go:59 +0xe4
html/template.(*Template).Execute(0xc20803ad80, 0x7f550e16f420, 0xc20805cd20, 0x7280c0, 0xc208032ea0, 0x0, 0x0)
    /usr/local/go/src/html/template/template.go:75 +0x3d
main.serveHome(0x7f550e16f328, 0xc20805cd20, 0xc208032ea0)
    /home/sasan/Works/Karina/Mobazi/Mon-Panel/routes.go:11 +0x136
net/http.HandlerFunc.ServeHTTP(0x7eb738, 0x7f550e16f328, 0xc20805cd20, 0xc208032ea0)
    /usr/local/go/src/net/http/server.go:1265 +0x41
net/http.(*ServeMux).ServeHTTP(0xc20803a6c0, 0x7f550e16f328, 0xc20805cd20, 0xc208032ea0)
    /usr/local/go/src/net/http/server.go:1541 +0x17d
net/http.serverHandler.ServeHTTP(0xc20805a0c0, 0x7f550e16f328, 0xc20805cd20, 0xc208032ea0)
    /usr/local/go/src/net/http/server.go:1703 +0x19a
net/http.(*conn).serve(0xc20805cc80)
    /usr/local/go/src/net/http/server.go:1204 +0xb57
created by net/http.(*Server).Serve
    /usr/local/go/src/net/http/server.go:1751 +0x35e

Answer 1

模板实际上可能包含多个要执行的"模板".这里你实际上有2个模板; 一个名为"test"的nil模板,带有自定义分隔符,以及一个名为"index.html"的已解析模板.

您可以将第一个命名为索引模板的名称

var sherrifTmpl = template.New("index.html").Delims("{[{", "}]}")

或者您可以通过名称调用模板 ExecuteTemplate

template.Must(sherrifTmpl.ParseFiles("index.html")).ExecuteTemplate(w, "index.html", r)

html/template在这种情况下,包裹仍然不应该恐慌.这是一个将在go1.5中修复的错误(目前已在git master中修复).