Re: Random broken images when generating dynamic images
On Wed, 23 Oct 2002 17:55:05 -0500 (CDT) Dave Rolsky [EMAIL PROTECTED] wrote: On a page with 5 different dynamic images (all generated by the same chunk of code, it's a set of graphs), I'll often see 1 or 2 as a broken image, but the rest work. Sometimes all 5 are ok. Unlikely to be your problem, but I had something similar once when running too few backend mod_perl httpds on a development box. Bye Paolo
Re: Random broken images when generating dynamic images
On Wed, Oct 23, 2002 at 05:55:05PM -0500, Dave Rolsky wrote: So here's the situation. I have some code that generates images dynamically. It works, mostly. Sometimes the image will show up as a broken image in the browser. If I reload the page once or twice, the image comes up fine. On a page with 5 different dynamic images (all generated by the same chunk of code, it's a set of graphs), I'll often see 1 or 2 as a broken image, but the rest work. Sometimes all 5 are ok. I tried out a scheme of writing them to disk with dynamically generated files, but since I still need to do some auth checking, they end up being served dynamically and I have the same problem. To make it even weirder, I just took a look at one of the image files that showed up as broken, and it's fine (I can't view it directly in my browser). I've seen the problem before. My solution was to save the dynamic images on disk and serve them just like plain 'ol static files from the front-end server. This way everything is served from the same Keep-Alive request. And apache does all the http/1.1 headers/chunked-encoding for me. Your MaxKeepAliveRequests would then be the culprit on your end but not likely unless its set really low. I'm not sure how the browser determines the equivalent limit. tcpdump showed that opera created a second keep-alive request after 10 images for me (could be limiting on bytes rather than requests ... don't know). You can still serve dynamicly and handle the custom auth w/ the backend and maintain the clients keep-alive. The current mod_proxy will maintain the clients keep-alive eventhough your backend has keepalive off. Be sure all the required http/1.1 components/headers are sent to maintain a keep-alive. I'm interested in what you finally work out. thanks, Ed
Re: Random broken images when generating dynamic images
On Thu, 24 Oct 2002, Paolo Campanella wrote: On a page with 5 different dynamic images (all generated by the same chunk of code, it's a set of graphs), I'll often see 1 or 2 as a broken image, but the rest work. Sometimes all 5 are ok. Unlikely to be your problem, but I had something similar once when running too few backend mod_perl httpds on a development box. I don't think this is it because I've seen this when testing on a system with plenty of backend httpds (MaxClients at 50 or so). -dave /*== www.urth.org we await the New Sun ==*/
Random broken images when generating dynamic images
So here's the situation. I have some code that generates images dynamically. It works, mostly. Sometimes the image will show up as a broken image in the browser. If I reload the page once or twice, the image comes up fine. On a page with 5 different dynamic images (all generated by the same chunk of code, it's a set of graphs), I'll often see 1 or 2 as a broken image, but the rest work. Sometimes all 5 are ok. I tried out a scheme of writing them to disk with dynamically generated files, but since I still need to do some auth checking, they end up being served dynamically and I have the same problem. To make it even weirder, I just took a look at one of the image files that showed up as broken, and it's fine (I can't view it directly in my browser). I can't for the life of me figure out what the heck is going on. It seems that the image data is just fine. Could the browser be timing out for some reason? This has been seen in multiple browsers too (Galeon and IE, at least) so it's not browser-specific. I'd love to fix the root cause, but a workaround would be fine too. The fundamental problem is that there's no way to not have some code involved in this process because there needs to be some auth checking before the image is served. Any help would be much appreciated. -dave /*== www.urth.org we await the New Sun ==*/
Re: Random broken images when generating dynamic images
On Wed, 23 Oct 2002, Dave Rolsky wrote: I have some code that generates images dynamically. It works, mostly. Sometimes the image will show up as a broken image in the browser. If I reload the page once or twice, the image comes up fine. I should mention that I'm using Mason, and I haven't yet tried playing with a non-Mason based solution, but I am making sure to clear Mason's buffers before serving the image, and I abort the (Mason) request immediately after the image data is sent, so I don't think Mason is causing the problem. -dave /*== www.urth.org we await the New Sun ==*/
Re: Random broken images when generating dynamic images
On Wed, Oct 23, 2002 at 05:55:05PM -0500, Dave Rolsky wrote: So here's the situation. I have some code that generates images dynamically. It works, mostly. Sometimes the image will show up as a broken image in the browser. If I reload the page once or twice, the image comes up fine. On a page with 5 different dynamic images (all generated by the same chunk of code, it's a set of graphs), I'll often see 1 or 2 as a broken image, but the rest work. Sometimes all 5 are ok. I tried out a scheme of writing them to disk with dynamically generated files, but since I still need to do some auth checking, they end up being served dynamically and I have the same problem. To make it even weirder, I just took a look at one of the image files that showed up as broken, and it's fine (I can't view it directly in my browser). I've seen the problem before. My solution was to save the dynamic images on disk and serve them just like plain 'ol static files from the front-end server. This way everything is served from the same Keep-Alive request. And apache does all the http/1.1 headers/chunked-encoding for me. Your MaxKeepAliveRequests would then be the culprit on your end but not likely unless its set really low. I'm not sure how the browser determines the equivalent limit. tcpdump showed that opera created a second keep-alive request after 10 images for me (could be limiting on bytes rather than requests ... don't know). You can still serve dynamicly and handle the custom auth w/ the backend and maintain the clients keep-alive. The current mod_proxy will maintain the clients keep-alive eventhough your backend has keepalive off. Be sure all the required http/1.1 components/headers are sent to maintain a keep-alive. I'm interested in what you finally work out. thanks, Ed
