[Pharo-dev] HTTPProgress Content-Length v.

Oct. 1, 2013

      For PharoLauncher, I am trying to get a progress bar going for the 
downloading the Template lists, but the total transfer size is not being 
filled in for the HTTPProgress announcement.  I've pulled out some code 
to Workspace script into [2] with the resulting Transcript result shown 
in [3].  I'm guessing this is due to the _"Transfer-Encoding: chunked"_ 
header clashing with the "Content-Length" header [1].  By putting a 
'self halt' in ZnStatusLine>>readFrom: and executing several "Transcript 
crShow: (ZnLineReader on: stream) nextLine" the real headers were found 
as shown in [4], from which it seems the Content-Length is faked-up 
after the download finishes, and no use for a progress bar.

So I only today discovered 'chunked' format, so I am curious... is there 
a particular advantage to use chunked for directory listing at 
"url=http://files.pharo.org/image/30/"  ?
Could it be changed to instead set Content-Length instead?
btw, This is only for the directory listing (which however takes 10 
seconds to get all). The zip files seem to set "Content-Length" when 
downloaded.

cheers -ben

[1] 
http://stackoverflow.com/questions/2419281/content-length-header-versus-chun...

"[2]start------------------Workspace-script----------"
workBlock :=
    [ ZnClient new
        signalProgress: true ;
        url: 'http://files.pharo.org/image/30/' ;
        enforceHttpSuccess: true ;
        beOneShot ;
        accept: 'text/html;charset=utf-8' ;
        enforceAcceptContentType: true ;
        logToTranscript ;
        get
    ].

UIManager default informUserDuring:
    [    :bar|
        [ workBlock value] on: HTTPProgress do:
        [    : progress |
            Transcript crShow:  '# ' , progress printString ,
                                '  total=' , progress total asString ,
                                '  amount=' , progress amount asString.
            bar label: progress printString.    
            progress isEmpty ifFalse: [ bar current: progress percentage ].
            progress resume.
        ].
    ].
"[2]end------------------Workspace-script----------"

"[3]start--------------Transcript------"
# HTTPProgress: Connecting to files.pharo.org  total=nil  amount=nil
2013-10-02 00:43:36 428852 I Wrote a ZnRequest(GET /image/30/)
2013-10-02 00:43:36 428852 D Sent headers
Accept: text/html;charset=utf-8
User-Agent: Zinc HTTP Components 1.0
Connection: close
Host: files.pharo.org
# HTTPProgress: Writing request  total=nil  amount=nil
# HTTPProgress: Reading response  total=nil  amount=nil
ZnUtils>>signalProgress: 16384  total: nil
# HTTPProgress: Tranferred 16.38k bytes ...  total=nil  amount=nil
ZnUtils>>signalProgress: 32768  total: nil
# HTTPProgress: Tranferred 32.77k bytes ...  total=nil  amount=nil
ZnUtils>>signalProgress: 49152  total: nil
# HTTPProgress: Tranferred 49.15k bytes ...  total=nil  amount=nil
ZnUtils>>signalProgress: 65536  total: nil
# HTTPProgress: Tranferred 65.54k bytes ...  total=nil  amount=nil
ZnUtils>>signalProgress: 81920  total: nil
# HTTPProgress: Tranferred 81.92k bytes ...  total=nil  amount=nil
ZnUtils>>signalProgress: 85434  total: nil
# HTTPProgress: Tranferred 85.43k bytes ...  total=nil  amount=nil
2013-10-02 00:43:38 428852 I Read a ZnResponse(200 OK 
text/html;h5ai=0.22.1;charset=UTF-8 85444B)
2013-10-02 00:43:38 428852 D Received headers
Date: Tue, 01 Oct 2013 16:43:34 GMT
Transfer-Encoding: chunked
Content-Length: 85444
Vary: Accept-Encoding
Server: Apache
Connection: close
Content-Type: text/html;h5ai=0.22.1;charset=UTF-8
2013-10-02 00:43:38 428852 T GET /image/30/ 200 85444B 1874ms
"[3]end--------------Transcript------"

"[4]start----------ZnStatusLine>>readReal-Headers--------"
HTTP/1.1 200 OK
Date: Tue, 01 Oct 2013 17:23:55 GMT
Server: Apache
Vary: Accept-Encoding
Connection: close
Transfer-Encoding: chunked
Content-Type: text/html;h5ai=0.22.1;charset=UTF-8
"[4]end-----------Real-Headers--------"

[Pharo-dev] HTTPProgress Content-Length v.

Ben Coman