Checking for custom field with conditional inside of an embed template

Question

I've decided to just test an idea for custom meta tags on every page without using Low Variable and try a native approach. The idea is to use an embed template with embed variables to check if a custom field is entered and if not use the global site meta description.

The embed template is:

{exp:channel:entries channel="{embed:channel_name}" dynamic="yes" disable="members|categories|pagination"}
    {if embed:meta_tag}
         {{embed:meta_tag}}
            {if no_results}
            blah
            {/if}

    {if:else}
          Nothing entered
    {/if}
    {if embed:meta_tag != ""}
         {{embed:meta_tag}}
            {if no_results}
            blah
            {/if}
    {/if}
    {if embed:meta_tag == ""}
          {gv_meta_desc}
    {/if}
 {/exp:channel:entries}

I then pass the embed template into my templates as

 {embed="embeds/template_file" channel_name="channel_name" meta_tag="meta_description"}

If the meta_description is entered, content will show. If not nothing will show. I cannot see an error or anything that would cause this to occur.

Answer 1

Your code works ok in EE 2.9 but versions below this, this should work:

{exp:channel:entries channel="{embed:channel}" dynamic="yes"}
   {if "{{embed:meta_tag}}" }
       {{embed:meta_tag}}
            {if no_results}
            blah
            {/if}
   {if:else}
       Nothing entered
   {/if}
   {if "{{embed:meta_tag}}" != ""}
       {{embed:meta_tag}}
       {if no_results}
               blah
        {/if}
   {/if}
   {if "{{embed:meta_tag}}" == ""}
       {gv_meta_desc}
   {/if}
{/exp:channel:entries}

In expressionengine 2.9, they rewrote the conditional parser, so in order to achieve this kind of effect in older versions, you need to double wrap all your embed var tags for conditionals.

Your first conditional was being rendered like:

   {if } {!-- blank if! --}
       {{embed:meta_tag}}
            {if no_results}
            blah
            {/if}
   {if:else}
       Nothing entered
   {/if}

You were passing in a blank variable, which I think was breaking the template. (See first response in this thread)