Re: [PHP] Re: Announcing Xaja, a PHP Reverse Ajax framework
I don't believe there is an equivalent in other languages. In Java, the closest match might be DWR for the Reverse Ajax approach, or maybe GWT for the no Javascript approach. I'm not completely sure, but I think nobody took exactly the same approach yet, because Xaja opens a large number of processes and connexions and most people believe that its architecture cannot adapt to thousands of users. For my part, since the vast majority of the applications I develop have less than 100 concurrent users, Xaja's architecture is perfect, and I hope it will spread in other frameworks and languages, because I find it really easier to develop applications with a events oriented architecture. David. Sancar Saran a écrit : On Saturday 14 July 2007 15:01:13 David Négrier wrote: Hi I just watching your screen cast, it has very good ideas. I wonder does any other language has same kind of aproach. Later or sooner this kind of aproach become must in web business. Regards Sancar. Indeed, Xaja relies on the keeping of an open connexion between the server and the browser. In fact, it uses, the Comet approach (which is a pain to implement in Javascript because the IE code and the Firefox code are completely different). (more information here: http://www.thecodingmachine.com/cmsDoc/xaja/trunk/architecture.html) The whole idea behind Xaja is to built a complete framework on top of the Comet-like javascript library that will enable the developer to write as few Javascript as possible. So, indeed, through the XajaController object, we are implementing a data driven programming library on top of the classical request/response HTTP protocol. Regarding performances: Indeed, since a connexion is kept open for each browser, this consumes a few connexions on the server (that's not a big problem). Each process also takes some memory. Xaja is still in an early stage of development and I haven't had the opportunity to run a full performance test, but basically, right now, I can tell that a simple applications takes 5 Mo of RAM per client. Which means that for 100 concurrent users, you need 500 Mo of RAM on your server. Now, the vast majority of the servers have less than 100 concurrent users, and at this early point in the development cycle of Xaja, I wouldn't recommend installing Xaja on a server that has more than 100 concurrent users! ;) Regards, David. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Re: Announcing Xaja, a PHP Reverse Ajax framework
On Saturday 14 July 2007 15:01:13 David Négrier wrote: Hi I just watching your screen cast, it has very good ideas. I wonder does any other language has same kind of aproach. Later or sooner this kind of aproach become must in web business. Regards Sancar. Indeed, Xaja relies on the keeping of an open connexion between the server and the browser. In fact, it uses, the Comet approach (which is a pain to implement in Javascript because the IE code and the Firefox code are completely different). (more information here: http://www.thecodingmachine.com/cmsDoc/xaja/trunk/architecture.html) The whole idea behind Xaja is to built a complete framework on top of the Comet-like javascript library that will enable the developer to write as few Javascript as possible. So, indeed, through the XajaController object, we are implementing a data driven programming library on top of the classical request/response HTTP protocol. Regarding performances: Indeed, since a connexion is kept open for each browser, this consumes a few connexions on the server (that's not a big problem). Each process also takes some memory. Xaja is still in an early stage of development and I haven't had the opportunity to run a full performance test, but basically, right now, I can tell that a simple applications takes 5 Mo of RAM per client. Which means that for 100 concurrent users, you need 500 Mo of RAM on your server. Now, the vast majority of the servers have less than 100 concurrent users, and at this early point in the development cycle of Xaja, I wouldn't recommend installing Xaja on a server that has more than 100 concurrent users! ;) Regards, David. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Re: Announcing Xaja, a PHP Reverse Ajax framework
You can't even be guaranteed to GET the client's IP address in their request, much less assume that it's going to be the same when you want to push data out to it!!! So any Xaja-like technology has to rely on keeping the HTTP connection open, really... Does seem pretty cool, though probably not scalable for heavily loaded servers. On Fri, July 13, 2007 1:59 pm, Nathan Nobbe wrote: On 7/13/07, Robert Cummings [EMAIL PROTECTED] wrote: I haven't looked at the code for Xaja and in no way do I want to subtract from its potential, but I'm going to guess that in some way it holds the HTTP connection open and as such is an expensive feature. Also, I'm not entirely sure, but isn't that the principle that Comet uses? As i said ive only imagined such a feature. In my imagination i wonder if it is possible to track the clients address in a data structure within the application. Then a connection could be established whenever a push was needed. I also think the app would have to track the last page a user requested in order to realize such an implementation. This *should* be feasible using sessions because whenever the client makes a new request the last page variable could be updated. I havent seen nor heard of Comet; would you mind providing a link? -nathan On 7/13/07, Robert Cummings [EMAIL PROTECTED] wrote: On Fri, 2007-07-13 at 14:28 -0400, Nathan Nobbe wrote: I have imagined being able to connect to a client browser and push changes to the client rather than have something sit on the client side and periodically wait for updates. or only update when the client refreshes the page manually. both of those antiquated options are ugly. the push technique discussed in this email is essentially leveraging the Observer design pattern. As i said i imagined it could be achieved via ajax, but wasnt sure on the implementation. im curious now to see it in action and pour through the Xaja code for the answer to the riddle! btw. i found myelf thinking of the pronouciation as ZahJah. I haven't looked at the code for Xaja and in no way do I want to subtract from its potential, but I'm going to guess that in some way it holds the HTTP connection open and as such is an expensive feature. Also, I'm not entirely sure, but isn't that the principle that Comet uses? Cheers, Rob. -- ... SwarmBuy.com - http://www.swarmbuy.com Leveraging the buying power of the masses! ... -- Some people have a gift link here. Know what I want? I want you to buy a CD from some indie artist. http://cdbaby.com/browse/from/lynch Yeah, I get a buck. So? -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Re: Announcing Xaja, a PHP Reverse Ajax framework
Indeed, Xaja relies on the keeping of an open connexion between the server and the browser. In fact, it uses, the Comet approach (which is a pain to implement in Javascript because the IE code and the Firefox code are completely different). (more information here: http://www.thecodingmachine.com/cmsDoc/xaja/trunk/architecture.html) The whole idea behind Xaja is to built a complete framework on top of the Comet-like javascript library that will enable the developer to write as few Javascript as possible. So, indeed, through the XajaController object, we are implementing a data driven programming library on top of the classical request/response HTTP protocol. Regarding performances: Indeed, since a connexion is kept open for each browser, this consumes a few connexions on the server (that's not a big problem). Each process also takes some memory. Xaja is still in an early stage of development and I haven't had the opportunity to run a full performance test, but basically, right now, I can tell that a simple applications takes 5 Mo of RAM per client. Which means that for 100 concurrent users, you need 500 Mo of RAM on your server. Now, the vast majority of the servers have less than 100 concurrent users, and at this early point in the development cycle of Xaja, I wouldn't recommend installing Xaja on a server that has more than 100 concurrent users! ;) Regards, David. Nathan Nobbe a écrit : I understand the use of AJAX to only update a subset of the DOM on a page, rather than rebuild the entire page. What i was getting at though is eliminating the busy-wait model by using the Observer pattern to push changes to the client only when the data has changed on the server side. This is decidedly more efficient in general and is more commonly referred to as *event driven programming* or *data driven programming*. it sounds like the only way to implement such a model over HTTP is by keeping the connection open; which in some circumstances may be appropriate. I have to say though, I never thought of using busy waiting to update just a portion of the DOM. It seems like almost a no-brainier, but since i havent worked w/ AJAX much it just never crossed my mind. That sounds like the most practical approach in general. -nathan On 7/13/07, Tijnema [EMAIL PROTECTED] wrote: On 7/13/07, Nathan Nobbe [EMAIL PROTECTED] wrote: On 7/13/07, Robert Cummings [EMAIL PROTECTED] wrote: This isn't possible since you can't request a connection to the client's machine. Only the other way around. hmm... in that case perhaps the open connection could be employed and the feature used selectively; only on certain pages for instance ? im thinking mainly of a monitoring page; like an app that shows a servers state, or stock quotes or something. the main reason i dont like a javascript timer refreshing the page is sometimes you dont want the whole page refreshed; especially when halfway through filling out a form on the page ;) -nathan Well, that's why AJAX is there, you do a check to a server to see if there's any new data to parse, if so, then you update (and probably only one or two divs on your site, and not the whole page) Keeping connection open isn't quite bad for sites that are visited a lot, as for each connection, a new port is opened to handle a client connection. While you think you're connected to port 80, it is actually redirected to another port (mostly from 3000 onwards). So, if you have a lot of visiters, you might reach the limit of ports, 65536 (0-65535). Some of them are already in use, so you end up to have a limit of about 65530 connections to keep open. For a normal site this isn't a problem, but if you count on shared hosts, with let's say 20 sites, then they can all handle about 3200 connections. Half of the users has probably more then one window open, which means another connection. So you end up to have a maximum of about 2000 visiters at same time for each site. Tijnema On 7/13/07, Robert Cummings [EMAIL PROTECTED] wrote: On Fri, 2007-07-13 at 14:59 -0400, Nathan Nobbe wrote: On 7/13/07, Robert Cummings [EMAIL PROTECTED] wrote: I haven't looked at the code for Xaja and in no way do I want to subtract from its potential, but I'm going to guess that in some way it holds the HTTP connection open and as such is an expensive feature. Also, I'm not entirely sure, but isn't that the principle that Comet uses? As i said ive only imagined such a feature. In my imagination i wonder if it is possible to track the clients address in a data structure within the application. Then a connection could be established whenever a push was needed. This isn't possible since you can't request a connection to the client's machine. Only the other way around. I also think the app would have to track the last page a user requested in order to realize
[PHP] Re: Announcing Xaja, a PHP Reverse Ajax framework
David Négrier wrote: Regarding the way Xaja is pronounced well that's a good question. Actually, I'm French and my pronunciation is... well... French ;), so I won't give you any advice on how to pronounce it. However, I will present Xaja in San Francisco at the Ajax Experience (a conference about Web 2.0 development). I will ask some people there if they can give me a clue on the way to pronounce it in English ;). I reckon it should be pronounced zah-jah in English. (the same Z sound as in Xavier) I wouldn't listen to the Americans in San Fran. Americans always pronounce English in a weird and colourful way (and yes, colourful has a U in it. get that right too!!!) :p Col -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Re: Announcing Xaja, a PHP Reverse Ajax framework
On 7/13/07, Colin Guthrie [EMAIL PROTECTED] wrote: I reckon it should be pronounced zah-jah in English. (the same Z sound as in Xavier) I wouldn't listen to the Americans in San Fran. Americans always pronounce English in a weird and colourful way (and yes, colourful has a U in it. get that right too!!!) :p Col I actually agree with Colin on part one and 2(a) of his message for the most part. I wouldn't enunciate a hard J on the second syllable, though, rather trading it for a 'zh' sound. Immediately upon reading it, I considered it to sound like ZAH-zhah. With regards to 2a, I agree that my fellow Americans over on the west coast, specifically San Francisco, speak a bit different than those of us in the northeast. Nowhere near as different as the south, but that's not the point. On points 2b and 2c (Americans always pronounce English in a weird and colourful way, and, yes, colourful has a U in it, respectively), I don't completely agree. Sure, we bastardized the language a bit, but considering Europeans bastardized it from Germanic in the first place, it's only fair. ;-P And to you, yes, colourful has a U in it. Well, guess what it does for us, too! Just not in the color part, but rather the ful part. So there! Finally, since I'm already off-topic, I may as well at least commend our more eastern friends (read: non-American English speakers) on understanding the difference between - and correctly using - the words theatre versus theater, and centre versus center correctly. /soapbox -- Daniel P. Brown [office] (570-) 587-7080 Ext. 272 [mobile] (570-) 766-8107 -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Re: Announcing Xaja, a PHP Reverse Ajax framework
On Jul 13, 2007, at 10:31 AM, Daniel Brown wrote: And to you, yes, colourful has a U in it. Well, guess what it does for us, too! Just not in the color part, but rather the ful part. So there! It's all about U isn't it? ;) -- Jason Pruim Raoset Inc. Technology Manager MQC Specialist 3251 132nd ave Holland, MI, 49424 www.raoset.com [EMAIL PROTECTED] -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Re: Announcing Xaja, a PHP Reverse Ajax framework
On Fri, 2007-07-13 at 10:40 -0400, Jason Pruim wrote: On Jul 13, 2007, at 10:31 AM, Daniel Brown wrote: And to you, yes, colourful has a U in it. Well, guess what it does for us, too! Just not in the color part, but rather the ful part. So there! It's all about U isn't it? ;) Humour us! :) Cheers, Rob. -- ... SwarmBuy.com - http://www.swarmbuy.com Leveraging the buying power of the masses! ... -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Re: Announcing Xaja, a PHP Reverse Ajax framework
On Fri, 2007-07-13 at 10:31 -0400, Daniel Brown wrote: On 7/13/07, Colin Guthrie [EMAIL PROTECTED] wrote: I reckon it should be pronounced zah-jah in English. (the same Z sound as in Xavier) I wouldn't listen to the Americans in San Fran. Americans always pronounce English in a weird and colourful way (and yes, colourful has a U in it. get that right too!!!) :p Col I actually agree with Colin on part one and 2(a) of his message for the most part. I wouldn't enunciate a hard J on the second syllable, though, rather trading it for a 'zh' sound. Immediately upon reading it, I considered it to sound like ZAH-zhah. I'm with Colin, I'd pronounce it ZahJah. Yah, Yah, that's would I would say. But really, it's up to it's creator how they would like it to be said :) Cheers, Rob. -- ... SwarmBuy.com - http://www.swarmbuy.com Leveraging the buying power of the masses! ... -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
[PHP] Re: Announcing Xaja, a PHP Reverse Ajax framework
Daniel Brown wrote: And to you, yes, colourful has a U in it. Well, guess what it does for us, too! Just not in the color part, but rather the ful part. So there! D'oh! You got me there :p Col -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Re: Announcing Xaja, a PHP Reverse Ajax framework
I have imagined being able to connect to a client browser and push changes to the client rather than have something sit on the client side and periodically wait for updates. or only update when the client refreshes the page manually. both of those antiquated options are ugly. the push technique discussed in this email is essentially leveraging the Observer design pattern. As i said i imagined it could be achieved via ajax, but wasnt sure on the implementation. im curious now to see it in action and pour through the Xaja code for the answer to the riddle! btw. i found myelf thinking of the pronouciation as ZahJah. -nathan On 7/13/07, Colin Guthrie [EMAIL PROTECTED] wrote: Daniel Brown wrote: And to you, yes, colourful has a U in it. Well, guess what it does for us, too! Just not in the color part, but rather the ful part. So there! D'oh! You got me there :p Col -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Re: Announcing Xaja, a PHP Reverse Ajax framework
On Fri, 2007-07-13 at 14:28 -0400, Nathan Nobbe wrote: I have imagined being able to connect to a client browser and push changes to the client rather than have something sit on the client side and periodically wait for updates. or only update when the client refreshes the page manually. both of those antiquated options are ugly. the push technique discussed in this email is essentially leveraging the Observer design pattern. As i said i imagined it could be achieved via ajax, but wasnt sure on the implementation. im curious now to see it in action and pour through the Xaja code for the answer to the riddle! btw. i found myelf thinking of the pronouciation as ZahJah. I haven't looked at the code for Xaja and in no way do I want to subtract from its potential, but I'm going to guess that in some way it holds the HTTP connection open and as such is an expensive feature. Also, I'm not entirely sure, but isn't that the principle that Comet uses? Cheers, Rob. -- ... SwarmBuy.com - http://www.swarmbuy.com Leveraging the buying power of the masses! ... -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Re: Announcing Xaja, a PHP Reverse Ajax framework
On 7/13/07, Robert Cummings [EMAIL PROTECTED] wrote: I haven't looked at the code for Xaja and in no way do I want to subtract from its potential, but I'm going to guess that in some way it holds the HTTP connection open and as such is an expensive feature. Also, I'm not entirely sure, but isn't that the principle that Comet uses? As i said ive only imagined such a feature. In my imagination i wonder if it is possible to track the clients address in a data structure within the application. Then a connection could be established whenever a push was needed. I also think the app would have to track the last page a user requested in order to realize such an implementation. This *should* be feasible using sessions because whenever the client makes a new request the last page variable could be updated. I havent seen nor heard of Comet; would you mind providing a link? -nathan On 7/13/07, Robert Cummings [EMAIL PROTECTED] wrote: On Fri, 2007-07-13 at 14:28 -0400, Nathan Nobbe wrote: I have imagined being able to connect to a client browser and push changes to the client rather than have something sit on the client side and periodically wait for updates. or only update when the client refreshes the page manually. both of those antiquated options are ugly. the push technique discussed in this email is essentially leveraging the Observer design pattern. As i said i imagined it could be achieved via ajax, but wasnt sure on the implementation. im curious now to see it in action and pour through the Xaja code for the answer to the riddle! btw. i found myelf thinking of the pronouciation as ZahJah. I haven't looked at the code for Xaja and in no way do I want to subtract from its potential, but I'm going to guess that in some way it holds the HTTP connection open and as such is an expensive feature. Also, I'm not entirely sure, but isn't that the principle that Comet uses? Cheers, Rob. -- ... SwarmBuy.com - http://www.swarmbuy.com Leveraging the buying power of the masses! ...
Re: [PHP] Re: Announcing Xaja, a PHP Reverse Ajax framework
On Fri, 2007-07-13 at 14:59 -0400, Nathan Nobbe wrote: On 7/13/07, Robert Cummings [EMAIL PROTECTED] wrote: I haven't looked at the code for Xaja and in no way do I want to subtract from its potential, but I'm going to guess that in some way it holds the HTTP connection open and as such is an expensive feature. Also, I'm not entirely sure, but isn't that the principle that Comet uses? As i said ive only imagined such a feature. In my imagination i wonder if it is possible to track the clients address in a data structure within the application. Then a connection could be established whenever a push was needed. This isn't possible since you can't request a connection to the client's machine. Only the other way around. I also think the app would have to track the last page a user requested in order to realize such an implementation. This *should* be feasible using sessions because whenever the client makes a new request the last page variable could be updated. I havent seen nor heard of Comet; would you mind providing a link? http://ajaxian.com/archives/comet-a-new-approach-to-ajax-applications Cheers, Rob. -- ... SwarmBuy.com - http://www.swarmbuy.com Leveraging the buying power of the masses! ... -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Re: Announcing Xaja, a PHP Reverse Ajax framework
On 7/13/07, Robert Cummings [EMAIL PROTECTED] wrote: This isn't possible since you can't request a connection to the client's machine. Only the other way around. hmm... in that case perhaps the open connection could be employed and the feature used selectively; only on certain pages for instance ? im thinking mainly of a monitoring page; like an app that shows a servers state, or stock quotes or something. the main reason i dont like a javascript timer refreshing the page is sometimes you dont want the whole page refreshed; especially when halfway through filling out a form on the page ;) -nathan On 7/13/07, Robert Cummings [EMAIL PROTECTED] wrote: On Fri, 2007-07-13 at 14:59 -0400, Nathan Nobbe wrote: On 7/13/07, Robert Cummings [EMAIL PROTECTED] wrote: I haven't looked at the code for Xaja and in no way do I want to subtract from its potential, but I'm going to guess that in some way it holds the HTTP connection open and as such is an expensive feature. Also, I'm not entirely sure, but isn't that the principle that Comet uses? As i said ive only imagined such a feature. In my imagination i wonder if it is possible to track the clients address in a data structure within the application. Then a connection could be established whenever a push was needed. This isn't possible since you can't request a connection to the client's machine. Only the other way around. I also think the app would have to track the last page a user requested in order to realize such an implementation. This *should* be feasible using sessions because whenever the client makes a new request the last page variable could be updated. I havent seen nor heard of Comet; would you mind providing a link? http://ajaxian.com/archives/comet-a-new-approach-to-ajax-applications Cheers, Rob. -- ... SwarmBuy.com - http://www.swarmbuy.com Leveraging the buying power of the masses! ...
Re: [PHP] Re: Announcing Xaja, a PHP Reverse Ajax framework
On 7/13/07, Nathan Nobbe [EMAIL PROTECTED] wrote: On 7/13/07, Robert Cummings [EMAIL PROTECTED] wrote: This isn't possible since you can't request a connection to the client's machine. Only the other way around. hmm... in that case perhaps the open connection could be employed and the feature used selectively; only on certain pages for instance ? im thinking mainly of a monitoring page; like an app that shows a servers state, or stock quotes or something. the main reason i dont like a javascript timer refreshing the page is sometimes you dont want the whole page refreshed; especially when halfway through filling out a form on the page ;) -nathan Well, that's why AJAX is there, you do a check to a server to see if there's any new data to parse, if so, then you update (and probably only one or two divs on your site, and not the whole page) Keeping connection open isn't quite bad for sites that are visited a lot, as for each connection, a new port is opened to handle a client connection. While you think you're connected to port 80, it is actually redirected to another port (mostly from 3000 onwards). So, if you have a lot of visiters, you might reach the limit of ports, 65536 (0-65535). Some of them are already in use, so you end up to have a limit of about 65530 connections to keep open. For a normal site this isn't a problem, but if you count on shared hosts, with let's say 20 sites, then they can all handle about 3200 connections. Half of the users has probably more then one window open, which means another connection. So you end up to have a maximum of about 2000 visiters at same time for each site. Tijnema On 7/13/07, Robert Cummings [EMAIL PROTECTED] wrote: On Fri, 2007-07-13 at 14:59 -0400, Nathan Nobbe wrote: On 7/13/07, Robert Cummings [EMAIL PROTECTED] wrote: I haven't looked at the code for Xaja and in no way do I want to subtract from its potential, but I'm going to guess that in some way it holds the HTTP connection open and as such is an expensive feature. Also, I'm not entirely sure, but isn't that the principle that Comet uses? As i said ive only imagined such a feature. In my imagination i wonder if it is possible to track the clients address in a data structure within the application. Then a connection could be established whenever a push was needed. This isn't possible since you can't request a connection to the client's machine. Only the other way around. I also think the app would have to track the last page a user requested in order to realize such an implementation. This *should* be feasible using sessions because whenever the client makes a new request the last page variable could be updated. I havent seen nor heard of Comet; would you mind providing a link? http://ajaxian.com/archives/comet-a-new-approach-to-ajax-applications Cheers, Rob. -- ... SwarmBuy.com - http://www.swarmbuy.com Leveraging the buying power of the masses! ... -- Vote for PHP Color Coding in Gmail! - http://gpcc.tijnema.info -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Re: Announcing Xaja, a PHP Reverse Ajax framework
On 7/13/07, Tijnema [EMAIL PROTECTED] wrote: Well, that's why AJAX is there, you do a check to a server to see if there's any new data to parse, if so, then you update (and probably only one or two divs on your site, and not the whole page) I understand the use of AJAX to only update a subset of the DOM on a page, rather than rebuild the entire page. What i was getting at though is eliminating the busy-wait model by using the Observer pattern to push changes to the client only when the data has changed on the server side. This is decidedly more efficient in general and is more commonly referred to as *event driven programming* or *data driven programming*. it sounds like the only way to implement such a model over HTTP is by keeping the connection open; which in some circumstances may be appropriate. I have to say though, I never thought of using busy waiting to update just a portion of the DOM. It seems like almost a no-brainier, but since i havent worked w/ AJAX much it just never crossed my mind. That sounds like the most practical approach in general. -nathan On 7/13/07, Tijnema [EMAIL PROTECTED] wrote: On 7/13/07, Nathan Nobbe [EMAIL PROTECTED] wrote: On 7/13/07, Robert Cummings [EMAIL PROTECTED] wrote: This isn't possible since you can't request a connection to the client's machine. Only the other way around. hmm... in that case perhaps the open connection could be employed and the feature used selectively; only on certain pages for instance ? im thinking mainly of a monitoring page; like an app that shows a servers state, or stock quotes or something. the main reason i dont like a javascript timer refreshing the page is sometimes you dont want the whole page refreshed; especially when halfway through filling out a form on the page ;) -nathan Well, that's why AJAX is there, you do a check to a server to see if there's any new data to parse, if so, then you update (and probably only one or two divs on your site, and not the whole page) Keeping connection open isn't quite bad for sites that are visited a lot, as for each connection, a new port is opened to handle a client connection. While you think you're connected to port 80, it is actually redirected to another port (mostly from 3000 onwards). So, if you have a lot of visiters, you might reach the limit of ports, 65536 (0-65535). Some of them are already in use, so you end up to have a limit of about 65530 connections to keep open. For a normal site this isn't a problem, but if you count on shared hosts, with let's say 20 sites, then they can all handle about 3200 connections. Half of the users has probably more then one window open, which means another connection. So you end up to have a maximum of about 2000 visiters at same time for each site. Tijnema On 7/13/07, Robert Cummings [EMAIL PROTECTED] wrote: On Fri, 2007-07-13 at 14:59 -0400, Nathan Nobbe wrote: On 7/13/07, Robert Cummings [EMAIL PROTECTED] wrote: I haven't looked at the code for Xaja and in no way do I want to subtract from its potential, but I'm going to guess that in some way it holds the HTTP connection open and as such is an expensive feature. Also, I'm not entirely sure, but isn't that the principle that Comet uses? As i said ive only imagined such a feature. In my imagination i wonder if it is possible to track the clients address in a data structure within the application. Then a connection could be established whenever a push was needed. This isn't possible since you can't request a connection to the client's machine. Only the other way around. I also think the app would have to track the last page a user requested in order to realize such an implementation. This *should* be feasible using sessions because whenever the client makes a new request the last page variable could be updated. I havent seen nor heard of Comet; would you mind providing a link? http://ajaxian.com/archives/comet-a-new-approach-to-ajax-applications Cheers, Rob. -- ... SwarmBuy.com - http://www.swarmbuy.com Leveraging the buying power of the masses! ... -- Vote for PHP Color Coding in Gmail! - http://gpcc.tijnema.info
