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Title: View Template Functions Desc: aah provides template functions to access configuration, request parameters, session data, flash, etc. In addition to default go lang template funcs. You can add custom or third party Template Funcs too. Keywords: template funcs, funcmap, template func map, aah template funcs

View Template Functions

By default Go lang provides set of template functions and aah provides template functions to access configuration, request parameters, security check, session values, flash values, etc.

Table of Contents

aah Template Funcs

Function Description Example
config Accessing application configuration from aah.App().Config() {{ config "format.datetime" }}
i18n Access internationalization and localization message from view templates {{ i18n . "label.pages.title.aboutus" }}
pparam Access Path parameter values {{ pparam . "userId" }}
fparam Access Form parameter values {{ fparam . "email" }}
qparam Access URL Query parameter values {{ qparam . "lang" }}
flash Access Flash values. Note: Flash value is deleted after accessing once {{ flash . "error.user.email.incorrect" }}
session Access Session object values {{ session . "Username" }}
include Refer here
rurl Create Route URL, Refer here
rurlm Create Route URL, Refer here
isauthenticated Refer here
hasrole Refer here
hasanyrole Refer here
hasallroles Refer here
ispermitted Refer here
ispermittedall Refer here
safeHTML Refer here

Func: include

Include and render template file from anywhere under <app-base-dir>/views/** sub-tree with ViewArgs.

Since v0.12.0 new behaviour introduced.

{{ include "/common/sidebar.html" . }}

{{ include "/users/form.html" . }}

Previous behaviour is deprecated, to be removed in subsequent future release.

<!-- from common directory --> 
{{ include "sidebar.html" . }}

Func: rurl

Creates the Route URL for the given route name with arguments. Additional arguments are discarded.

  • How to access sub-domain URL for reverse route on root domain template file?
    • Ans: Use sub-domain (the one use have used in routes.conf) prefix before the route name
  • How to access root-domain URL for reverse route on sub-domain template file?
    • Ans: Use root. as prefix before the route name
  • How to I get host url for root domain or sub-domain on template file?
    • Ans: host is the keyword or virtual route name
      • For example: this is applicable to rurlm func too.
        • {{ rurl . "host" }} - on root domain template file
        • {{ rurl . "root.host" }} - on sub-domain template file
        • {{ rurl . "docs.host" }} - on root domain template file access sub-domain host URL
// route name and arguments
// Path: /users/:userId/addresses/:addressId
{{ rurl . "user_address_info"  .UserId .Addresses.AddressId }}

// route name
// Path: /login.html
{{ rurl . "login" }}

// ==================================
// How to access sub-domain url by route name?
// Ans: use
{{ rurl . "docs.index"}}

Func: rurlm

Creates the Route URL for given route name with map arguments. Additional arguments added as URL query parameters.

// route name and arguments
// Path: /v1/users/:userId/addresses/:addressId
{{ rurlm . "user_address_info" .MapArguments }}

// route name
// Path: /login.html
{{ rurlm . "login" }}

Func: isauthenticated

Returns the value of ctx.Subject().IsAuthenticated from current request subject.

<!-- show logout option if user is authenticated -->
{{ if isauthenticated . }}
  <a href="/logout">Logout</a>
{{ end }}

Func: hasrole

Returns true, if Subject (aka User) has given role otherwise false.

{{ if hasrole . "manager" }}
  <!-- You have a role "manager" -->
{{ end }}

Func: hasanyrole

Returns true, if Subject (aka User) has any of the given roles otherwise false.

{{ if hasanyrole . "manager" "dayshift" }}
  <!-- You have any one of the above role -->
{{ end }}

Func: hasallroles

Returns true, if Subject (aka User) has all the given roles otherwise false.

{{ if hasallroles . "role1" "role2" "role3" }}
  <!-- You have all the roles, congrats -->
{{ end }}

Func: ispermitted

Returns true if Subject (aka User) has given permission otherwise false.

{{ if ispermitted . "newsletter:read,write" }}
   <!-- You have permission, you may read or write newsletter -->
{{ end }}

Func: ispermittedall

Returns true if Subject (aka User) has all the given permissions otherwise false.

{{ if ispermittedall . "newsletter:read,write" "newsletter:12345" }}
   <!-- You have permission, you may read or write newsletter of 12345 -->
{{ end }}

Func: safeHTML

Go template strips the HTML comment while rendering the template file. To preserve HTML comment or any special char use safeHTML template func. Of-course use it with care.

Note: Use only if you trust the HTML source, since it preserves the HTML content without escaping.

<!-- For example: -->
{{ safeHTML `<!--[if lt IE 9]>
    <script src="//oss.maxcdn.com/html5shiv/3.7.2/html5shiv.min.js"></script>
    <script src="//oss.maxcdn.com/respond/1.4.2/respond.min.js"></script>
<![endif]-->` }}

Adding your custom Funcs or Third-Party Funcs

You add custom template func using aah.App().AddTemplateFunc.

func init() {
	aah.App().AddTemplateFunc(template.FuncMap{
		"myfuncname": func() string {
			return "mycustom function value"
		},
	})
}

Third-Party Funcs

Adding https://github.com/leekchan/gtf

func init() {
  aah.App().AddTemplateFunc(gtf.GtfFuncMap)
}

Adding https://github.com/Masterminds/sprig

func init()  {
  aah.App().AddTemplateFunc(sprig.FuncMap())
}