The generate sitemap <lastmod> is wrong(inaccuracy)!

[DeppWang]

The hexo-generator-sitemap plugins generated sitemap.xml that <lastmod> corresponding the last modification time of the source folder file, but the <lastmod> should corresponding the last modification time of the html file.

the sitemap.xml example:

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"> 
  <url>
    <loc>http://www.example.com/foo</loc>
    <lastmod>2018-06-04T18:00:15+00:00</lastmod> <!--The time last modification of the `foo.html`.-->
  </url>
</urlset>

I found [GSC Help] have a tips:

Google reads the <lastmod> value, but if you misrepresent this value, we will stop reading it.

• source: Manage your sitemaps: Build and submit a sitemap

If the sitemap <lastmod> is wrong, meaning the sitemap not effect?

About lastmod

---

append in 2020.04.16:

Because my sitemap cann't be read by GSC, I guess may be caused by the wrong <lastmod>.

It cause my article cann't be indexed in time. Almost need a week!

Your sitemap can be read in GSC? Your posted article can be searchable in next day?

If your sitemap can be read, and the <lastmod> don't inconsistent, So the <lastmod> don't matter in sitemap!

If your sitemap can not be read, but your posted article can be searchable in next day. Please reply me, I need your help.

[flashlab]

you can modify sitemap.xml or create external template as your own demand. Like this: post.updated.toISOString().substring(0, 10) Hope it will help you

[SukkaW]

@flashlab @DeppWang

If you guys are sure there is something wrong with lastmod, feel free to open a new pull request.

[DeppWang]

@flashlab Thanks, ask a question: Your sitemap can be read in GSC?

[flashlab]

@DeppWang @SukkaW tested myself Please check #94

[DeppWang]

@SukkaW I found your article can be indexed in time. Ask a question: Your sitemap can be read in GSC?

[DeppWang]

@flashlab Sorry, my eyes deceive me.

The following words reserved:

If sitemap can be read in GSC, the <lastmod> is not a issue.

If <lastmod> is a issue. Can't to change <lastmod> solove it, need to get html file last modification time, or remove <lastmod>.

[curbengh]

2018-06-04T18:00:15+00:00 does conform to the W3C Datetime/ISO 8601 format as specified by the protocol.

Edit: I tested 2018-06-04T18:00:15+00:00 with Yandex's sitemap validator and it is valid.

Perhaps Google expected/perfer 2018-06-04T18:00:15.000Z which should be the format generated by this plugin.

Can I have your Node version and "package.json"? Output of $ node -v and $ npm ls --depth 0?

In the meantime, I'll check my GSC.

---

It cause my article cann't be indexed in time. Almost need a week!

May I know when did your first add your site to GSC?

If I remember correctly, GSC (and other web crawlers) don't re-crawl new site as frequently, after a while if the crawler notice the site has consistent update, only then it will update more often.

[DeppWang]

@curbengh , Thanks your reply.

1. 2018-06-04T18:00:15+00:00 was copied from protocol. My sitemap.xml <lastmod> format is like 2018-06-04T18:00:15.000Z. I didn't notcie the difference of the both(a mistake). I rather express the difference between the local md file last modified time and online html file last modified time. May be the difference don't matter. My sitemap.xml: https://depp.wang/sitemap.xml. After test: Even though I remove the <lastmod> of sitemap.xml, the GSC also can't read my sitemap.xml.

2. I use hexo-aciton deploy blog, this is the hexo env. I don't think it's related to env.

   

3. I first added my site to GSC in 2017.

I guess it may be that the weight of my site is too low, so GSC does not read my sitemap.xml. Now, Google Spider should indexes my articles through the homepage, so it very slow.

Your sitemap.xml can be read in time?

[curbengh]

Your sitemap.xml can be read in time?

Roughly every 4 days. I added it last year.

My sitemap.xml: https://depp.wang/sitemap.xml

I notice all <lastmod> values are the same, which I think is the deployment time. Perhaps GSC finds it unusual and ignore it.

I have two suggestions (you can try all):

1. Use post.date only, this requires custom template.
   • Add the following content to "source/.sitemap.xml":

     <?xml version="1.0" encoding="UTF-8"?>
     <urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
     {% for post in posts %}
     <url>
     <loc>{{ post.permalink | uriencode }}</loc>
     {% if post.date %}
     <lastmod>{{ post.date.toISOString().substring(0, 10) }}</lastmod>
     {% endif %}
     </url>
     {% endfor %}
     </urlset>

   • Configure this plugin to use the above sitemap:

     _config.yml
     sitemap:
     template: ./source/.sitemap.xml

2. GSC also supports RSS. Install hexo-generator-feed and add https://depp.wang/atom.xml to GSC. Do not remove sitemap from GSC.
   • When you first add this, GSC might show "fetch error", wait for a day (don't remove), it will read just fine.

[DeppWang]

1. This step I had done. Because I use github action deploy blog, the action env will clone all files again each time. so the lastmod are the same. There is no good way to solve this issue.
2. I had added atom.xml to GSC, follow your suggestion. GSC now show "Couldn't fetch", may be as your said, GSC need time.

Thinks your suggestions.

[curbengh]

the action env will clone all files again each time. so the lastmod are the same.

My suggested template doesn't use post.updated; it only uses post.date (derived from a post's front matter) so "lastmod" should be unique.

[DeppWang]

I didn't notice the details, I have updated it.

Thanks very much!

[curbengh]

https://github.com/hexojs/hexo-generator-sitemap/pull/94, released in 2.1.0.

[DeppWang]

@curbengh Hi, I am coming again 😂, same old problem. atom.xml still "Coun't fetch" .

GSC said they can use the Atom 1.0 or RSS 2.0 as a sitemap, My atom.xml is Atom 1.0, I check the format is right. It is possible that I use the Cloudfare as a DNS causing it? I have no idea. I try to feedback to google support, but no reply.

What direction shou I take to check for error? Can you give me a suggestion, thx.

[curbengh]

I use Cloudflare as well and my atom.xml issue resolved itself within a few days. Can you access to http://yoursite.com/atom.xml.gz? Alternative is to switch to RSS format and try again.

[DeppWang]

My https://depp.wang/atom.xml.gz can't access, your site atom.xml.gz can download the xml. I will try to use the RSS, hope it can useful. Thanks for your reply.