hook while downloading from html port [http][port]

Scott, this is gold! I added a tag on the subject to be sure rebol.org indexes this properly, this really is a worth-while exercise, thanks for all the time you put on this, it will surely open up the mysterious port handling for many rebolers out there! -MAx ----- Original Message ----- From: "Jones, Scott" Sent: Thursday, April 15, 2004 8:35 PM Subject: [REBOL] Re: hook while downloading from html port From: Anton Rolls AR> Scott, I think you are a bit negative about transfer rates. :) AR> Surely there is a way. .... It was one of those things were as soon as I sent my email, I, too, thought of a way to show progress, but our satellite signals times are limited. My guess is that there will already be 3 more ways to do it by the time this arrives! Not unlike Anton's way in using read, I capture the actual bytes read from the return of read-io and accumulate these in a variable. If the site provides content length, then the patch can compare sent to expected. Unfortunately, not all servers/websites send the content length. At the end of the http scheme, and the variable "bytes-transferred", as in: ... cache-size: 5 user-agent: "REBOL View 1.2.10.3.1" bytes-transferred: 0 ] Then change the read function to (watch for line wrap): read: func [ port "An open port spec" data "A buffer to use for the read" /local bytes-read ][ net-utils/net-log ["low level read of " port/state/num "bytes"] bytes-read: read-io port/sub-port data port/state/num bytes-transferred: bytes-transferred + bytes-read if port/locals/headers/content-length <> none [print [to-integer (bytes-transferred / (to-integer port/locals/headers/content-length) * 100) percent ]] bytes-read ] Reading a page in which the server gives content-length will allow the calculation of percent received. I realized that the read function needs to return the bytes, read, hence the last line. Expanding on the idea, I decided for fun to try to create a visual feedback method that gives progress bar when the content-length is known, or simple accumulated bytes retrieved, when content-length was unknown. It requires a fair amount of patching. Starting with a fresh copy of the http scheme, one first alters the continue-post function: continue-post: func [/tunnel] [ response-line: system/words/pick port/sub-port 1 net-utils/net-log response-line either none? response-line [do error] [ either none? result: select either tunnel [tunnel-actions] [response-actions] response-code: to-integer second parse response-line none [do error] [do get result] ] if show-progress [ either port/locals/headers/content-length <> none [ progress-message/pane: layout/origin/offset [p: progress] 0x0 0x0 show progress-message ][ progress-message/pane: layout/origin/offset [t: text 200x16] 0x0 0x0 show progress-message ] ] ] Then following the close block and build-port further down, one inserts these lines .... ] build-port ;insert following lines if all [block? port/state/custom post-data: find port/state/custom to-lit-word 'progress block? post-data] [ show-progress: true progress-message: get to-word select port/state/custom to-lit-word 'progress ] Then one changes the close function: close: func [port][ if show-progress [ progress-message/pane: layout/origin/offset [t: text 200x16] 0x0 0x0 show progress-message t/text: "Done!" show t show-progress: none ] system/words/close port/sub-port bytes-transferred: 0 ] One changes the read function: read: func [ port "An open port spec" data "A buffer to use for the read" /local bytes-read ][ net-utils/net-log ["low level read of " port/state/num "bytes"] bytes-read: read-io port/sub-port data port/state/num bytes-transferred: bytes-transferred + bytes-read if show-progress [ either port/locals/headers/content-length <> none [ p/data: bytes-transferred / (to-integer port/locals/headers/content-length) show p ;loop 10000000 [] ;uncomment to see fast pages load ][ t/text: bytes-transferred show t ;loop 10000000 [] ] ] bytes-read ] Finally, one adds variables to the end of the scheme: ..... user-agent: "REBOL View 1.2.10.3.1" bytes-transferred: 0 show-progress: progress-message: p: t: none ] One uses the custom refinement to pass the reference to a VID box: view layout [ f: field 300x24 button "Get Page" [ read/custom trim to-url f/text ['progress :my-pane] ] my-pane: box 200x16 button "Exit" [quit] ] When one types in a url from a website where the server gives the content-length, the box gets a progress bar embedded, which is then updated based on the percentage of bytes read. When the url is served from a server that does not give the content-length, then the bytes retrieved are displayed. After completed, the progress box is converted to text that says "Done!" I have commented out some do nothing loops in case your downloads are too fast, and you are trying to see the changes at work. I was just about to send this when I received the most recent set of emails, including Max's own patch on read-net. Oh well, it still may prove useful to him or someone else in another context and/or to take advantage of all the extra features of the http protocol. --Scott Jones