英文:
template.Execute(): invalid memory address or nil pointer dereference
问题
我正在尝试使用自定义分隔符的Go html/template。
然而,我可以解析和执行我的 "index.html" 文件,但是当我尝试更改模板的分隔符时,我遇到以下错误:
运行时错误:无效的内存地址或空指针解引用 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种方式:
package main
import (
"html/template"
"net/http"
)
func serveHome(w http.ResponseWriter, r *http.Request) {
template.Must(template.ParseFiles("index.html")).Execute(w, r)
}
或者:
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)
}
一切都正常工作。我甚至尝试捕获 ParseFiles 的错误。但是仍然没有运气:
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 panic 的信息:
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
英文:
I am trying to use Go html/template with custom delimiters.
However, I can Parse and Execute my "index.html" file, whenever I am trying to change my templates Delimiters I face the following error:
runtime error: invalid memory address or nil pointer dereference goroutine
Here is my code:
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)
}
If I try any of the followings:
package main
import (
"html/template"
"net/http"
)
func serveHome(w http.ResponseWriter, r *http.Request) {
template.Must(template.ParseFiles("index.html")).Execute(w, r)
}
Or:
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)
}
Everything works. I even tried to catch ParseFiles error. But still no luck:
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)
}
I can't see where I am doing wrong. I would be grateful if any of you could help me on this issue.
Update 1:
Here is the panic:
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
答案1
得分: 8
一个模板实际上可以包含多个要执行的“模板”。在这里,你实际上有两个模板;一个名为“test”的空模板,使用自定义分隔符,和一个名为“index.html”的解析模板。
你可以将第一个模板命名为与你的索引模板相同的名称:
var sherrifTmpl = template.New("index.html").Delims("{[{", "}]}")
或者你可以通过名称调用模板,使用ExecuteTemplate
:
template.Must(sherrifTmpl.ParseFiles("index.html")).ExecuteTemplate(w, "index.html", r)
在这种情况下,html/template
包仍然不应该发生panic。这是一个bug,在go1.5中将被修复(目前在git主分支中已修复)。
英文:
A template may actually contain more than one "template" to execute. Here you actually have 2 templates; a nil template named "test" with custom delimiters, and a parsed template named "index.html".
You can either name the first the same name as your index template
var sherrifTmpl = template.New("index.html").Delims("{[{", "}]}")
or you can call the template by name with ExecuteTemplate
template.Must(sherrifTmpl.ParseFiles("index.html")).ExecuteTemplate(w, "index.html", r)
The html/template
package still shouldn't panic in this case. This is a bug that will be fixed in go1.5 (currently fixed in git master).
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