Avoiding dual compression in SAP web AS
Few SDNners encountered the problems(Zip-File stored in Mime-Repository ?) with dual compression/gzip done by SAP web AS.
I encountered the same problem while hosting a Adobe flash mime in WebAS. Dual gzip Compression made the browser ignore the first 2KB (Refernce: http://support.microsoft.com/kb/312496). Once the browser caches the mime, flash player was able to play the movie. But on the first load I could never play the movie.
As of WebAS 6.40, http mime compression logic works as follows:
Compress only if
a) client protocol >= HTTP/1.1
b) client can decode gzip documents (based on ‘accept-encoding’ parameter)
c) running plattform support this feature
This logic is documented in method CL_HTTP_SERVER_NET::IF_HTTP_SERVER~SET_COMPRESSION
As mentioned in the blog , we can also use the following profile parameters to disable the compression.
ict/min_compression_size = default: .gif,.zip,.cs,.rar,.arj,.z,.gz,.tar,.lzh,.cab,.hqx,.ace,.jar,.ear, .war,.css,.pdf,.js,.gzip,.uue,.bz2,.iso,.sda,.sar
Note provides more information on the patch level
These prameters are available only in webAS 6.40 and 7.0 starting certain service packs. This doesnot offer the flexibility to selectively disable the compression at the application level.