Golang : How to use if, eq and print properly in html template



Tags : golang if eq print html-template text-template li-active

Alright, just a simple problem that took me a while to get it right. Putting the solution down here for my own future reference. The problem that I was trying to solve is to print out the word active whenever the URL segment match certain word. For instance,

 http://domain.com/addrow

the URL first segment is the word addrow and therefore in the generated HTML code should have the <li class="active"> for Add Row. Such as this

  <ul>
 <li class="active"><a href="/addrow" class="">Add Row</a></li>
 <li class=""><a href="/deleterow" class="">Delete Row</a></li>
  </ul>

To do this properly with html template language in Golang. First, create a function to get the current URI.

  // GetURISegment - return URL item from a given position
  func GetURISegment(r *http.Request, position int) string {
 uriSegments := strings.Split(r.URL.Path, "/")
 return uriSegments[position]
  }

and follow by

 templateDataMap["CurrentSegment"] = GetURISegment(r, 1)
 // my own stuff, you should use your own
 var dashboardPageNavigation = template.Must(template.New("dashboardPageNavigation").Parse(navigation.NavigationHTML)) 

the templateDataMap variable will be passed to NavigationHTML template.

In the NavigationHTML, check if the current URI segment name equals to the word that matches the navigation item names. If yes, print out the word active

  <ul>
 <li class="{{if(eq .CurrentSegment "addproperty")}}{{print "active"}}{{else}}{{print ""}}{{end}}"><a href="/addproperty" class="">Add Property</a></li>
 <li class="{{if(eq .CurrentSegment "deleteproperty")}}{{print "active"}}{{else}}{{print ""}}{{end}}"><a href="/deleteproperty" class="">Delete Property</a></li>
  </ul>

Too hard to read?

  <ul>
 <li class="{{if(eq .CurrentSegment "addproperty")}}
 {{print "active"}}
 {{else}}
 {{print ""}}
 {{end}}">
 <a href="/addproperty" class="">Add Property</a>
 </li>
 <li class="{{if(eq .CurrentSegment "deleteproperty")}}
 {{print "active"}}
 {{else}}
 {{print ""}}
 {{end}}">
 <a href="/deleteproperty" class="">Delete Property</a>
 </li>
  </ul>

Hope this helps and happy coding!

References:

https://socketloop.com/tutorials/golang-get-uri-segments-by-number-and-assign-as-variable-example

https://golang.org/pkg/text/template/#hdr-Functions <-- text/template but applicable to html/template as well

https://stackoverflow.com/questions/44240003/how-to-add-conditional-sentences-in-template

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  See also : Golang : Populate dropdown with html/template example



Tags : golang if eq print html-template text-template li-active

By Adam Ng

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