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A
Aleksandar34715023f1z9
Inspiring
March 5, 2024
Answered

Adding canonical link in the head section (SEO)

  • March 5, 2024
  • 2 replies
  • 2353 views

Hello there. I have a website with over 5 thousand pages there but none of them have cannonical links included. My question here is, is it possible to add something like: 

<link rel="canonical" href="##page_url##" />

Add this in the head section of html page. Now, here is the deal, will  this affect my SEO? Will this change apply only when the page loads?

 

Note: When I say page_url above, it's an actual URL page is connected with. If index.cfm page is on https://test.com/potato , then href of the cannonical should be exactly that. 

 

    Correct answer Aleksandar34715023f1z9

    I did this and it seems to work:

     

    <cfoutput>
    <cfset protocol = cgi.SERVER_PORT_SECURE ? "https" : "http">
    <cfset scriptNameWithoutIndex = ListDeleteAt(cgi.SCRIPT_NAME, ListLen(cgi.SCRIPT_NAME, '/'), '/')>
    <cfset fullURL = "#protocol#://#cgi.SERVER_NAME##scriptNameWithoutIndex#">
    <cfif len(cgi.QUERY_STRING)>
        <cfset fullURL = "#fullURL#?#cgi.QUERY_STRING#">
    </cfif>
    <link rel="canonical" href="#fullURL#" />
</cfoutput>

    2 replies

    K
    Kishore Raju Satha
    New Participant
    May 19, 2025

     

    Yes, you can and should add the canonical tag in the <head> section of each HTML page, especially if your website currently lacks them.

    About <link rel="canonical" href="##page_url##" />

    The line itself is valid, but ##page_url## must be replaced dynamically with the actual full URL of the current page. Since your pages are using ColdFusion (.cfm), you can generate the correct canonical URL using server-side code.

    Example in ColdFusion (CFML):

     

     
    <cfset canonical_url = "https://" & CGI.SERVER_NAME & CGI.SCRIPT_NAME> <link rel="canonical" href="#canonical_url#" />

     

     

     
    <link rel="canonical" href="https://test.com/potato" />

    Make sure not to include unnecessary query parameters unless they lead to significantly different content.

    Impact on SEO

    Yes, adding a canonical tag will affect SEO, and generally in a positive way if done correctly.

    Benefits:

    • Helps search engines understand the preferred version of a page, which reduces duplicate content issues.

    • Consolidates ranking signals for similar or duplicate URLs (e.g., ones with session IDs or tracking parameters).

    • Improves crawl efficiency.

    Risks (if implemented incorrectly):

    • Pointing all pages to the same canonical (like the homepage) can hurt rankings.

    • Using broken or invalid URLs can confuse search engines.

    • Using relative URLs instead of absolute URLs can lead to indexing problems.

    Does it apply only when the page loads?

    Yes, search engines read the canonical tag when the page is crawled. If the canonical tag is generated dynamically, it must appear in the rendered HTML at the time of crawl.

    However, it won't retroactively fix previously indexed versions until those pages are crawled again. You can speed up that process using Google Search Console's URL Inspection Tool.

    Recommendation

    • Add the canonical tag generation to your main layout or header template, so it's applied site-wide.

    • Test on a few pages to ensure correct output.

    • Use absolute URLs.

    • Avoid including unnecessary query strings in canonical URLs unless they are essential for content differentiation.

    Kishore
    Charlie Arehart
    Charlie Arehart
    Community Expert
    March 6, 2024

    I can offer a suggestion from the CFML technical perspective (I can't speak to the SEO-worthiness of your goal here, but others may have an opinion--or you can seek that info elsewhere).

     

    If your point is you want to cause the link tag to appear in the head tags of the page--but you are already past the point of the head having been created, there IS a CFML tag to help with that, called cfhtmlhead. Check out the docs for that.

     

    And as for obtaining programatically the URL of the running page, there is no single variable in CF that offers that, but see the cgi.script_name for thepath and filename, and cgi.query_string for any querystring, etc. Do a cfdump of the cgi scope to see other available fields. (And someone may propose some java code that can somehow obtain the full URL from the underlying servlet classes within CF.)

    /Charlie (troubleshooter, carehart. org)
      A
      Aleksandar34715023f1z9AuthorCorrect answer
      Inspiring
      March 6, 2024

      I did this and it seems to work:

       

      <cfoutput>
    <cfset protocol = cgi.SERVER_PORT_SECURE ? "https" : "http">
    <cfset scriptNameWithoutIndex = ListDeleteAt(cgi.SCRIPT_NAME, ListLen(cgi.SCRIPT_NAME, '/'), '/')>
    <cfset fullURL = "#protocol#://#cgi.SERVER_NAME##scriptNameWithoutIndex#">
    <cfif len(cgi.QUERY_STRING)>
        <cfset fullURL = "#fullURL#?#cgi.QUERY_STRING#">
    </cfif>
    <link rel="canonical" href="#fullURL#" />
</cfoutput>
      Charlie Arehart
      Charlie Arehart
      Community Expert
      March 15, 2024

      Where can I use "cfhtmlhead" to achieve what you just said? I am not much familiar with all of this and ChatGPT helped me regarding this code above. 


      Did you read the docs link I offered? It shows an example, and you can use it anywhere you like. 

      /Charlie (troubleshooter, carehart. org)
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