There is one file on my site that had a space in the name; on my old site, this link worked: http://dada.pink/scarsdale/Statement 20140527.pdf

Now that I've moved to Ikiwiki, that doesn't work. So I moved the file here: http://dada.pink/scarsdale/Statement_20140527.pdf

Is there a better approach to maintaining this link than setting an alias in Apache?

You can add the space character to the wiki_file_chars argument in your setup file. -- Jon

a space character is not allowed in a url; user agents that read one usually represent it in percent encoded form (%20). if you use that, things also work for direct links, which i assume caused the problem (for both the links in the original description render correctly): [[http://dada.pink/scarsdale/Statement%2020140527.pdf]] renders http://dada.pink/scarsdale/Statement%2020140527.pdf.

spaces are allowed in internal pages because wiki page names are not urls per se but converted using conversion rules -- this allows people to not think about url rules and just link to pages, but when you're linking outside ikiwiki, some strings just aren't valid urls. --chrysn