It's probably worth noting that a meta refresh tag - see http://blooberry.com/indexdot/html/tagpages/m/meta.htm for some docs - is one that would look like this:
<meta http-equiv="Refresh" content="3; URL=http://localhost:65001/message"; /> But what this is doing, in essence, is creating an http header that would look like this: Refresh: 3; URL=http://localhost:65001/message In other words, rather than doing this: MYTEMPLATE=: 0 : 0 HTTP/1.1 200 OK Content-Type: text/html; charset=utf-8 Connection: close <html> <head> <meta http-equiv="Refresh" content="3; URL=http://localhost:65001/message"; /> </head> <body> <pre> PAGECONTENT </pre> </body> </html> ) (or, optionally, eliminating the html and body tags, since the browser should reconstruct them for us) you could achieve the same thing by doing this: MYTEMPLATE=: 0 : 0 HTTP/1.1 200 OK Content-Type: text/html; charset=utf-8 Connection: close Refresh: 3; URL=http://localhost:65001/message <pre> PAGECONTENT </pre> ) You could also probably remove the '; URL=http://localhost:65001/message' part - I think the browser would use the page's url if the refresh url is not specified. Finally, note that those name: value HTTP headers can be arranged in any order. I could go on, but hopefully this is enough to understand something about this option. Thanks, -- Raul On Tue, Sep 5, 2017 at 9:18 AM, Stefano Lanzavecchia <s...@apl.it> wrote: > A META header in the <Head> section of the HTML page can force a recurrent > refresh. The first article Google found on the subject is this one: > http://www.htmlgoodies.com/tutorials/getting_started/article.php/3479551 The > article also shows a micro-snippet in JavaScript to obtain a similar effect > on a user click. > > In order to obtain a similar effect under program control, where the server > decides when it's time to upgrade, one needs to keep a channel opened between > the browser and the server. This implies tricky JavaScript code client-side > and tricky code server side. Modern browser can leverage so-called websockets > (https://en.wikipedia.org/wiki/WebSocket) as long as the server is up to the > game. There are fallback strategies > (https://stackoverflow.com/questions/7807066/how-signalr-works-internally/7874352#7874352). > In general, having a full-duplex communication between a browser and a web > server is possible but it's not trivial and its complexity depends, among > various other things, on the level of compatibility required. Personally, > before embarking in anything more complex, I would try and see if the Meta > Refresh tag is good enough. > > Good luck! > -- > Stefano > > -----Original Message----- > From: Programming [mailto:programming-boun...@forums.jsoftware.com] On Behalf > Of Raul Miller > Sent: martedì 5 settembre 2017 14:54 > To: Programming forum <programm...@jsoftware.com> > Subject: Re: [Jprogramming] How can I auto-refresh a JHS app page? > > That's pretty much it. The browser is in control here, and jijx is only > indirectly in control as a result. > > Probably the simplest would be to put something like Refresh: 3 in the http > headers in your MYTEMPLATE (before the first blank line). But I haven't > tested that - I probably need to upgrade my jhs implementation before your > code would work for me. > > Thanks, > > -- > Raul > > > On Tue, Sep 5, 2017 at 8:27 AM, Ian Clark <earthspo...@gmail.com> wrote: >> Currently I'm hacking it by using Keyboard Maestro to execute a timer which >> reloads the message URL every 3 seconds. >> >> I guess much the same thing could be done using Javascript embedded in >> message.ijs? – if I knew any Javascript. >> >> Another expedient is to write out the message display to a textfile >> (~/message.txt) and open it using TextWrangler. This (unlike TextEdit) >> refreshes its display window whenever message.txt is rewritten. >> >> But these expedients are inelegant. I guess web browsers were not designed >> to do this sort of thing. (Or designed not to do this sort of thing?) >> >> On Tue, Sep 5, 2017 at 2:59 AM, Ian Clark <earthspo...@gmail.com> wrote: >> >>> Suppose I am a JHS coder, working with the J session (the jijx page), and >>> have written an app called "message" (say). This generates a page of data >>> in response to the URL: >>> >>> http://localhost:65001/message >>> >>> which I choose to display in a separate browser window. Let's call it the >>> message window. >>> >>> If I execute some phrase in jijx which changes the content of the message >>> window, then in the normal course of things I would need to manually reload >>> the page in order to see the altered data. For example (in Safari) by >>> activating the message window and clicking the symbol: "Reload this page". >>> >>> How can I write a verb (to be executed in jijx) which refreshes the >>> message window without having to do that? >>> >>> >> ---------------------------------------------------------------------- >> For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
