media_sideload_image() should replace spaces and %20's in URLs to dashes

[kingkool68]

I wrote a script to import content by scraping the HTML from a site. Yuck! Some of the image file names have spaces in them. DOUBLE YUCK!

I needed to use media_sideload_image() to import them into WordPress' media library. But the only way to successfully download the image is to first replace the space characters with %20. Then WordPress saves the new filename with %20's in them and WordPress multisite's .htaccess rules despise filenames with %20 in them.

Here is how I fixed it:

$file_array['name'] = basename($matches[0]);

becomes

$file_array['name'] = preg_replace('/\s|%20/', '-', basename($matches[0]));

Need an image with a space in the filename? Use this ​http://www.pewforum.org/uploadedImages/Topics/Issues/Social_Welfare/John%20DiIulio2.jpg

#16330, #21116