Hi Ben, On 01 Oct 2013, at 19:48, Ben Coman <[email protected]> wrote:
> 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. Completely correct! I am happy you made it this far and were able to understand the specs and code. > 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. The whole idea of chunked transfer encoding is to make it easier for the server: it does not have to buffer and compute a total size upfront. BTW, there are other cases in HTTP where Content-Length is not set as well. It is just how it is. And yes that means silly progress indications. Sven > cheers -ben > > > [1] > http://stackoverflow.com/questions/2419281/content-length-header-versus-chunked-encoding > > "[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--------" > >
