Wikimedia Commons API query to get count of sub categories and photos in a category

Question

I want to query a Wikimedia Commons category and get the count of sub categories and photos in a category. For example when you look at the web page "Category:Collections of the Brooklyn Museum" in Wikimedia Commons, you get the list of subcategories.

One of the subcategories

European art in the Brooklyn Museum‎ (7 C, 301 F)

has the numbers 7 C and 301 F which means this has 7 categories and 301 images.

How do I query the Wikimedia Commons to get this category and image count information of subcategories?

I tried the following queries

http://commons.wikimedia.org/w/api.php?action=query&list=categorymembers&cmlimit=100&cmtitle=Category:Collections%20of%20the%20Brooklyn%20Museum

which gives me the category members of the category.

I can do an action render query which produces the html representation from which I can scrape the 7 C and 301 F count information.

What query can I use to get this count information without the html scraping?

Answer 1

You can use prop=categoryinfo for this.

For example, the query:

http://commons.wikimedia.org/w/api.php?action=query&prop=categoryinfo&titles=Category:Collections%20of%20the%20Brooklyn%20Museum

returns:

<api>
  <query>
    <pages>
      <page pageid="21253813" ns="14" title="Category:Collections of the Brooklyn Museum">
        <categoryinfo size="105" pages="0" files="88" subcats="17" />
      </page>
    </pages>
  </query>
</api>