id,summary,reporter,owner,description,type,status,priority,milestone,component,version,severity,resolution,keywords,cc
23021,Last-Modified header always set to 1970... when it is blank. Make browser cannot refresh cache.,slene,ryan,"In #22258, the Last-Modified header set blank when user login.

A response with a blank Last-Modified header will be set to ""Thu, 01 Jan 1970 00:00:00 GMT"" in some server. The browser will be always send a If-Modified-Since header ""Thu, 01 Jan 1970 00:00:00 GMT"". and the server response a 304 status code. Make the browser can not refresh cache.

In php5.2 the Last-Modified header always blank. But php5.3 has header_remove remove it. 
The Last-Modified header should be remove form $headers array when it blank.

sorry my bad english...",defect (bug),closed,normal,3.5.1,General,3.5,normal,fixed,has-patch commit fixed-major,slene