Weibo + IDNs + linkification

Sina Weibo recently implemented linkification of IDNs for the TLDs .公司 .网络 .中国. I have tested and the Weibo IDN links now work but not with all browsers. I tested with firefox, safari and chrome on OSX. Only chrome works. Firefox used to work but stopped working with v42.0.

If you have a weibo account you can try out my test IDN linkification posts at
Alternatively http://RUrikk7 (which should resolve to http://宿迁物流.公) is the direct link to weibo's link server for one of my test links.

IMHO, there are some issues with Weibo's link service wrt IDNs. In the http/1.1 response header, http://RUrikk7 returns, in the Location: field, the address (宿迁物流.公司) as Unicode utf8. 

① To my knowledge, http/1.1 header fields are restricted to US-ASCII. Why is Weibo returning the Unicode form in the Location field?
② The Unicode form of an IDN is used for presentation to the user but behind the scenes the punycode form of an IDN is used. Why is Weibo not returning the punycode form? I frequently monitor http traffic for IDNs and until Weibo I have always seen punycode being returned in relevant fields.

Thus, Weibo should return  the punycode form of IDNs in the HTTP/1.1 response header and then all browsers would work fine.

Thoughts? Is there a standard that specifies exactly what should happen in cases like above?

André Schappo

Received on Monday, 14 December 2015 11:02:12 UTC