英文:
How do I use nested Templates from a constant string variable in Go?
问题
我一直在尝试在Go中使用嵌套模板，但是示例或帮助文档对我没有帮助，而其他3个博客中的示例也不是我想要的（其中一个接近，可能是唯一的方法，但我想确保）
好的，所以我的代码是用于App Engine的，在这里我将对服务器进行urlfetch，然后我想显示一些结果，比如Response、头部和正文。
const statusTemplate = `
{{define "RT"}}
Status - {{.Status}}
Proto - {{.Proto}}
{{end}}
{{define "HT"}}
{{range $key, $val := .}}
{{$key}} - {{$val}}
{{end}}
{{end}}
{{define "BT"}}
{{.}}
{{end}}
{{define "MT"}}
<html>
<body>
<pre>
-- Response --
{{template "RT"}}
-- Header --
{{template "HT"}}
-- Body --
{{template "BT"}}
</pre>
</body>
</html>
{{end}}
{{template "MT"}}`
func showStatus(w http.ResponseWriterm r *http.Request) {
/*
* code to get:
* resp as http.Response
* header as a map with the header values
* body as an string wit the contents
*/
t := template.Must(template.New("status").Parse(statusTemplate)
t.ExecuteTemplate(w, "RT", resp)
t.ExecuteTemplate(w, "HT", header)
t.ExecuteTemplate(w, "BT", body)
t.Execute(w, nil)
}
我的代码实际上输出了具有正确值的RT、HT和BT模板，然后输出了空的MT模板（MT代表主模板）。
那么...我如何使用字符串变量中的嵌套表单，使上述示例工作？
英文:
I have been trying to use nested templates in Go, however the Examples or help documents are not helping me, and examples in 3 other blogs are not what I'm looking for (one is close and maybe the only way but I want to make sure)
OK, so my code is for App Engine, in here I will be doing an urlfetch to a server, and then I want to show some results, like the Response, headers, and body.
const statusTemplate = `
{{define "RT"}}
Status - {{.Status}}
Proto - {{.Proto}}
{{end}}
{{define "HT"}}
{{range $key, $val := .}}
{{$key}} - {{$val}}
{{end}}
{{end}}
{{define "BT"}}
{{.}}
{{end}}
{{define "MT"}}
<html>
<body>
<pre>
-- Response --
{{template "RT"}}
-- Header --
{{template "HT"}}
-- Body --
{{template "BT"}}
</pre>
</body>
</html>
{{end}}
{{template "MT"}}`
func showStatus(w http.ResponseWriterm r *http.Request) {
/*
* code to get:
* resp as http.Response
* header as a map with the header values
* body as an string wit the contents
*/
t := template.Must(template.New("status").Parse(statusTemplate)
t.ExecuteTemplate(w, "RT", resp)
t.ExecuteTemplate(w, "HT", header)
t.ExecuteTemplate(w, "BT", body)
t.Execute(w, nil)
}
My code actually outputs the RT, HT, and BT templates with the correct values, and then it outputs the MT template empty (MT stands for main template).
So... How can I use nested forms from a string variable so that an example as the above works?
答案1
得分: 1
我认为你尝试使用嵌套模板的方法是错误的。如果你想在嵌套模板中定义.，你必须为调用嵌套模板时提供一个参数，就像你在ExecuteTemplate函数中做的那样：
{{define "RT"}}
状态 - {{.Status}}
协议 - {{.Proto}}
{{end}}
{{define "HT"}}
{{range $key, $val := .}}
{{$key}} - {{$val}}
{{end}}
{{end}}
{{define "BT"}}
{{.}}
{{end}}
{{define "MT"}}
<html>
<body>
<pre>
-- 响应 --
{{template "RT" .Resp}}
-- 头部 --
{{template "HT" .Header}}
-- 主体 --
{{template "BT" .Body}}
</pre>
</body>
</html>
{{end}}
{{template "MT"}}
你似乎忽略了一个重要的部分，那就是模板不会封装状态。当你执行一个模板时，引擎会根据给定的参数评估模板，然后将生成的文本写出。它不会保存参数或为将来的调用生成的任何内容。
##文档
相关部分的文档：
> ###操作
>
> 这是操作的列表。"参数"和"管道"是数据的评估，下面详细定义。
>
> ...
>
> {{template "name"}}
> 使用空数据执行指定名称的模板。
>
> {{template "name" pipeline}}
> 使用管道的值将.设置为指定名称的模板执行。
>
> ...
希望这能解决你的问题。
英文:
I think the approach you try with nested templates is wrong. If you want . to be defined inside a nested template, you have to supply an argument to the call to the nested template, just as you do with the ExecuteTemplate function:
{{define "RT"}}
Status - {{.Status}}
Proto - {{.Proto}}
{{end}}
{{define "HT"}}
{{range $key, $val := .}}
{{$key}} - {{$val}}
{{end}}
{{end}}
{{define "BT"}}
{{.}}
{{end}}
{{define "MT"}}
<html>
<body>
<pre>
-- Response --
{{template "RT" .Resp}}
-- Header --
{{template "HT" .Header}}
-- Body --
{{template "BT" .Body}}
</pre>
</body>
</html>
{{end}}
{{template "MT"}}
The important part you seem to miss is that templates do not encapsulate state. When you execute a template, the engine evaluates the template for the given argument and then writes out the generated text. It does not save the argument or anything that was generated for future invocations.
##Documentation
Relevant part of the documentation:
> ###Actions
>
> Here is the list of actions. "Arguments" and "pipelines" are
> evaluations of data, defined in detail below.
>
> ...
>
> {{template "name"}}
> The template with the specified name is executed with nil data.
>
> {{template "name" pipeline}}
> The template with the specified name is executed with dot set
> to the value of the pipeline.
>
> ...
I hope this clears up things.
答案2
得分: 0
请看这个教程：
http://javatogo.blogspot.com
里面解释了如何使用嵌套模板。
英文:
have a look at this tutorial:
http://javatogo.blogspot.com
there it is explained how to use nested templates.
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