使用场景： 我们希望在模板里面动态解析指定的模板文件。

这个似乎使用go语言的模板嵌套 template 可以实现，不过模板嵌套声明里面是不支持使用变量的， 如：{{template "模板文件名" .}}  这里的"模板文件名"不能使用变量，原因我们另外分析， 所以只能是静态嵌套其他模板，不能实现动态嵌套其他模板！

golang动态模板解析实现思路

       要实现模板文件的动态解析， 我们可以通过在自定义模板函数的方式来实现。即 这个函数接收一个 模板文件变量 和模板解析参数 然后将模板文件解析为 HTML后返回给调用模板，这样就实现了模板的动态解析。 【ps： 如果你有更好的思路，欢迎反馈分享 ：）】

        

golang HTML动态模板解析实现代码 示例

import ("bytes""html/template""path/filepath""github.com/spf13/viper" // 配置信息解析，可以使用其他你喜欢的
)// 获取所有自定义模板函数
func GetFuncs() template.FuncMap {// fmap map[string]anyreturn template.FuncMap{"TplInclude":  TplInclude,}
}// 动态模板解析函数 将指定的模板文件渲染为html内容后返回
//
//	tplFile 模板文件 这个可以是相对exe所在文件夹的路径 或者绝对路径
//	datas 可选参数  要应用到模板文件中的数据 通常为map格式
//
// 返回可直接渲染页面的 template.HTML 格式的字符串
// @author: TekinTian <tekinTian@gmail.com>
// @see https://dev.tekin.cn
func TplInclude(tplFile string, datas ...interface{}) template.HTML {var data interface{} // 应用到模板中的数据,默认空if len(datas) > 0 {data = datas[0] // 从可选参数中获取}// 从配置文件中获取分隔符delss := viper.GetStringSlice("viewer.delimiters")if len(delss) != 2 {delss = []string{"", ""} // 使用默认的分隔符,这里留空go最后解析的时候就会使用默认的分隔符 {{ }} 详情src/text/template/parse/lex.go}// 获取*template.Template对象 注意如果用到了自定义分隔符,自定义函数,则需要再这里重新注册t := template.New(tplFile).Delims(delss[0], delss[1]).Funcs(GetFuncs())// 解析模板文件 注意这里的模板文件路径必须是相对于exe运行文件所在的路径 或者 绝对路径tpl, err := t.ParseFiles(filepath.Join("templates", tplFile))if err != nil {return template.HTML(err.Error())}// 新建一个字符串缓存 writer, 解析后的模板内容将写入到这里// 这里如果是直接输出到浏览器的话用浏览器的writer即可, gin的输出writer为 c.Writer// 我们这里不直接输出到浏览器,而是输出到模板文件中,所以用这个自定义的writer接收后转为字符串输出到模板中.buf := bytes.NewBufferString("")// 渲染模板if err := tpl.Execute(buf, data); err == nil {return template.HTML(buf.String()) // 将缓存中的所有数据以html格式放回 注意必须是template.HTML格式 否则页面不会被解析} else {return template.HTML(err.Error())}
}

总结

动态模板解析这里的关键点就是如何将指定的模板文件解析为HTML字符串，一般我们常见的就是直接将模板文件解析后输出到浏览器， 而这里是将模板文件解析后返回HTML格式的字符串，这就需要我们使用自定义的writer来接收模板解析后的内容，然后将这些内容返回， 注意这里在返回的时候必须使用 template.HTML 类型， 否则你返回的字符串将是被转码后的html，是不会被浏览器渲染的。

附 template包中定义的返回类型参考

我们上面就用到了下面的这个 HTML类型， 他其实就是一个string类型的类型定义， 当然如果我们希望实现动态渲染css,js 等其他内容，也需要使用下面定义的对应的类型才行哦。

package template// Strings of content from a trusted source.
type (// CSS encapsulates known safe content that matches any of://   1. The CSS3 stylesheet production, such as `p { color: purple }`.//   2. The CSS3 rule production, such as `a[href=~"https:"].foo#bar`.//   3. CSS3 declaration productions, such as `color: red; margin: 2px`.//   4. The CSS3 value production, such as `rgba(0, 0, 255, 127)`.// See https://www.w3.org/TR/css3-syntax/#parsing and// https://web.archive.org/web/20090211114933/http://w3.org/TR/css3-syntax#style//// Use of this type presents a security risk:// the encapsulated content should come from a trusted source,// as it will be included verbatim in the template output.CSS string// HTML encapsulates a known safe HTML document fragment.// It should not be used for HTML from a third-party, or HTML with// unclosed tags or comments. The outputs of a sound HTML sanitizer// and a template escaped by this package are fine for use with HTML.//// Use of this type presents a security risk:// the encapsulated content should come from a trusted source,// as it will be included verbatim in the template output.HTML string// HTMLAttr encapsulates an HTML attribute from a trusted source,// for example, ` dir="ltr"`.//// Use of this type presents a security risk:// the encapsulated content should come from a trusted source,// as it will be included verbatim in the template output.HTMLAttr string// JS encapsulates a known safe EcmaScript5 Expression, for example,// `(x + y * z())`.// Template authors are responsible for ensuring that typed expressions// do not break the intended precedence and that there is no// statement/expression ambiguity as when passing an expression like// "{ foo: bar() }\n['foo']()", which is both a valid Expression and a// valid Program with a very different meaning.//// Use of this type presents a security risk:// the encapsulated content should come from a trusted source,// as it will be included verbatim in the template output.//// Using JS to include valid but untrusted JSON is not safe.// A safe alternative is to parse the JSON with json.Unmarshal and then// pass the resultant object into the template, where it will be// converted to sanitized JSON when presented in a JavaScript context.JS string// JSStr encapsulates a sequence of characters meant to be embedded// between quotes in a JavaScript expression.// The string must match a series of StringCharacters://   StringCharacter :: SourceCharacter but not `\` or LineTerminator//                    | EscapeSequence// Note that LineContinuations are not allowed.// JSStr("foo\\nbar") is fine, but JSStr("foo\\\nbar") is not.//// Use of this type presents a security risk:// the encapsulated content should come from a trusted source,// as it will be included verbatim in the template output.JSStr string// URL encapsulates a known safe URL or URL substring (see RFC 3986).// A URL like `javascript:checkThatFormNotEditedBeforeLeavingPage()`// from a trusted source should go in the page, but by default dynamic// `javascript:` URLs are filtered out since they are a frequently// exploited injection vector.//// Use of this type presents a security risk:// the encapsulated content should come from a trusted source,// as it will be included verbatim in the template output.URL string// Srcset encapsulates a known safe srcset attribute// (see https://w3c.github.io/html/semantics-embedded-content.html#element-attrdef-img-srcset).//// Use of this type presents a security risk:// the encapsulated content should come from a trusted source,// as it will be included verbatim in the template output.Srcset string
)