Re: [Lazarus] fpWeb long process progress
On Tue, 14 Aug 2012, Leonardo M. Ramé wrote: On 2012-08-14 11:47:41 -0300, Marcos Douglas wrote: IMHO, maybe is better to use CGI gateway to capture the requests and, for each one them, start a process -- this method will use a file to write the log of process, as Leonardo and Michael said. Yes, in my case, I know in advance the process wouldn't take more than one minute, but for longer processes the gateway is a nice idea. Well, I use the code I sent to take backups or fix databases, which takes 30 minutes easily. The browser just polls ever so-and-so time. Michael.-- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] fpWeb long process progress
On 08/15/2012 12:14 AM, Leonardo M. Ramé wrote: in my case, I know in advance the process wouldn't take more than one minute, I feel that (without some special configuration) a normal web server will kill a standard CGI process that takes more than just a few seconds before returning. Please check the specs of your Webserver and let us know what you find. -Michael -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] fpWeb long process progress
On 15 August 2012 09:28, Michael Schnell mschn...@lumino.de wrote: On 08/15/2012 12:14 AM, Leonardo M. Ramé wrote: in my case, I know in advance the process wouldn't take more than one minute, I feel that (without some special configuration) a normal web server will kill a standard CGI process that takes more than just a few seconds before returning. Apache defaults to 300 seconds for its core timeout (which includes mod_cgi). Different modules have their own configuration settings, e.g. php have a max_execution_time, which defaults to 30 seconds afaik. Henry -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] fpWeb long process progress
On Mon, 13 Aug 2012, Leonardo M. Ramé wrote: On 2012-08-13 15:15:56 -0700, leledumbo wrote: How can I send responses by intervals? AFAIK that's not the way web application works. It's the client that should be querying the server in a regular interval (using AJAX request perhaps). The server can track current progress status and return that right away when asked. Yes, I know that, but I thought Lazarus have something easy to develop such process. The way I'm thinking of implementing is this: 1) The client app asks the server (a CGI process) for a process ID, for example 123, by calling getProcId. 2) Using this ID, the client calls the time-consuming task, passing the ID. for example, runTask(Id). At this time, the server launches a program passing the ID for the task. This must be a multi-thread program, because it can be asked for running many tasks, and can be asked for the status of each task. The program only finishes when the last task is ended. 3) The client calss a getProcStatus(ID) method. The server, using IPC or Pipes, asks the already-launched process for its status. I have code which does exactly that. It's used in production. It's unix-only, however (it relies on fork and exec). If you're interested, I can send you the code. Michael.-- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] fpWeb long process progress
AFAIK, a web application uses the plain old standard mechanism, a web server uses to work with a CGI application. it start the application and when same ends, the web server retrieves its output and sends it to the browser. So the web application just does not live long to be able to wait for anything. To create a longer living web enabled process it takes a lot more effort. You can try several approaches: - purely propriety: Use a second process (a long living daemon) and have the web application communicate with same (e.g. via TCP/IP or Pipe) - fast CGI: here the (Apache) Web Server does exactly this communication on it's own account - ISAPI: here a (Microsoft) Web server communicates with a DLL My colleagues do a combination of (1) and (3) with one of their (Delphi) project very successfully: They created a very simple ISAPI DLL (using RemObjects to do the ISAPI communication) They created a Windows service and used RemObjects (using the Windows Message transport) to have the ISAPI DLL communicate with the service. (RemObjects is a commercial product that is specified to work as well with Delphi as with FreePascal.) -Michael -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] fpWeb long process progress
On 08/14/2012 09:06 AM, michael.vancann...@wisa.be wrote: I have code which does exactly that. It's used in production. It's unix-only, however (it relies on fork and exec). GREAT ! It would be great if this would be integrated in the Lazarus distribution (as a special Application) or if it would be available as an add-on package. Thanks, -Michael -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] fpWeb long process progress
On 2012-08-14 09:47:41 +0200, Michael Schnell wrote: AFAIK, a web application uses the plain old standard mechanism, a web server uses to work with a CGI application. it start the application and when same ends, the web server retrieves its output and sends it to the browser. So the web application just does not live long to be able to wait for anything. To create a longer living web enabled process it takes a lot more effort. You can try several approaches: - purely propriety: Use a second process (a long living daemon) and have the web application communicate with same (e.g. via TCP/IP or Pipe) - fast CGI: here the (Apache) Web Server does exactly this communication on it's own account - ISAPI: here a (Microsoft) Web server communicates with a DLL My colleagues do a combination of (1) and (3) with one of their (Delphi) project very successfully: They created a very simple ISAPI DLL (using RemObjects to do the ISAPI communication) They created a Windows service and used RemObjects (using the Windows Message transport) to have the ISAPI DLL communicate with the service. (RemObjects is a commercial product that is specified to work as well with Delphi as with FreePascal.) -Michael Thanks Michael, I'm testing a different approach, based on a temporary file. It works this way: 1) The client asks for a TaskId, for example 1234. 2) With the TaskId generated by the server, the client calls a CGI method called runLongTask(myTaskId). This method writes a temporary file which name is the taskId. 3) The client can ask for status by using a method called getTaskStatus(myTaskId). This way I can run a long task without having to create a daemon. Regards, -- Leonardo M. Ramé http://leonardorame.blogspot.com -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] fpWeb long process progress
On 2012-08-14 09:06:20 +0200, michael.vancann...@wisa.be wrote: On Mon, 13 Aug 2012, Leonardo M. Ramé wrote: On 2012-08-13 15:15:56 -0700, leledumbo wrote: How can I send responses by intervals? AFAIK that's not the way web application works. It's the client that should be querying the server in a regular interval (using AJAX request perhaps). The server can track current progress status and return that right away when asked. Yes, I know that, but I thought Lazarus have something easy to develop such process. The way I'm thinking of implementing is this: 1) The client app asks the server (a CGI process) for a process ID, for example 123, by calling getProcId. 2) Using this ID, the client calls the time-consuming task, passing the ID. for example, runTask(Id). At this time, the server launches a program passing the ID for the task. This must be a multi-thread program, because it can be asked for running many tasks, and can be asked for the status of each task. The program only finishes when the last task is ended. 3) The client calss a getProcStatus(ID) method. The server, using IPC or Pipes, asks the already-launched process for its status. I have code which does exactly that. It's used in production. It's unix-only, however (it relies on fork and exec). If you're interested, I can send you the code. Michael. Yes please, send me the code. Regards, -- Leonardo M. Ramé http://leonardorame.blogspot.com -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] fpWeb long process progress
On Tue, 14 Aug 2012, Leonardo M. Ramé wrote: On 2012-08-14 09:47:41 +0200, Michael Schnell wrote: AFAIK, a web application uses the plain old standard mechanism, a web server uses to work with a CGI application. it start the application and when same ends, the web server retrieves its output and sends it to the browser. So the web application just does not live long to be able to wait for anything. To create a longer living web enabled process it takes a lot more effort. You can try several approaches: - purely propriety: Use a second process (a long living daemon) and have the web application communicate with same (e.g. via TCP/IP or Pipe) - fast CGI: here the (Apache) Web Server does exactly this communication on it's own account - ISAPI: here a (Microsoft) Web server communicates with a DLL My colleagues do a combination of (1) and (3) with one of their (Delphi) project very successfully: They created a very simple ISAPI DLL (using RemObjects to do the ISAPI communication) They created a Windows service and used RemObjects (using the Windows Message transport) to have the ISAPI DLL communicate with the service. (RemObjects is a commercial product that is specified to work as well with Delphi as with FreePascal.) -Michael Thanks Michael, I'm testing a different approach, based on a temporary file. It works this way: 1) The client asks for a TaskId, for example 1234. 2) With the TaskId generated by the server, the client calls a CGI method called runLongTask(myTaskId). This method writes a temporary file which name is the taskId. 3) The client can ask for status by using a method called getTaskStatus(myTaskId). This way I can run a long task without having to create a daemon. That is exactly what I do. Michael.-- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] fpWeb long process progress
On Tue, 14 Aug 2012, Leonardo M. Ramé wrote: I have code which does exactly that. It's used in production. It's unix-only, however (it relies on fork and exec). If you're interested, I can send you the code. Michael. Yes please, send me the code. Sent in private mail. Michael.-- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] fpWeb long process progress
On 08/14/2012 04:27 PM, Leonardo M. Ramé wrote: 2) With the TaskId generated by the server, the client calls a CGI method called runLongTask(myTaskId). I don't know if it's a goad idea to allow a standard CGI to do a long action before returning top the WebServer. At least the WebServer might kill the child task after a few seconds if it thinks it has run wild. Maybe it is possible to configure the appropriate Timeout in the web server parameters. -Michael -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] fpWeb long process progress
On Tue, Aug 14, 2012 at 11:34 AM, Michael Schnell mschn...@lumino.de wrote: On 08/14/2012 04:27 PM, Leonardo M. Ramé wrote: 2) With the TaskId generated by the server, the client calls a CGI method called runLongTask(myTaskId). I don't know if it's a goad idea to allow a standard CGI to do a long action before returning top the WebServer. +1 At least the WebServer might kill the child task after a few seconds if it thinks it has run wild. Maybe it is possible to configure the appropriate Timeout in the web server parameters. IMHO, maybe is better to use CGI gateway to capture the requests and, for each one them, start a process -- this method will use a file to write the log of process, as Leonardo and Michael said. Marcos Douglas -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] fpWeb long process progress
On 2012-08-14 11:47:41 -0300, Marcos Douglas wrote: IMHO, maybe is better to use CGI gateway to capture the requests and, for each one them, start a process -- this method will use a file to write the log of process, as Leonardo and Michael said. Yes, in my case, I know in advance the process wouldn't take more than one minute, but for longer processes the gateway is a nice idea. Regards, -- Leonardo M. Ramé http://leonardorame.blogspot.com -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] fpWeb long process progress
How can I send responses by intervals? AFAIK that's not the way web application works. It's the client that should be querying the server in a regular interval (using AJAX request perhaps). The server can track current progress status and return that right away when asked. -- View this message in context: http://free-pascal-lazarus.989080.n3.nabble.com/Lazarus-fpWeb-long-process-progress-tp4025614p4025615.html Sent from the Free Pascal - Lazarus mailing list archive at Nabble.com. -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] fpWeb long process progress
On 2012-08-13 15:15:56 -0700, leledumbo wrote: How can I send responses by intervals? AFAIK that's not the way web application works. It's the client that should be querying the server in a regular interval (using AJAX request perhaps). The server can track current progress status and return that right away when asked. Yes, I know that, but I thought Lazarus have something easy to develop such process. The way I'm thinking of implementing is this: 1) The client app asks the server (a CGI process) for a process ID, for example 123, by calling getProcId. 2) Using this ID, the client calls the time-consuming task, passing the ID. for example, runTask(Id). At this time, the server launches a program passing the ID for the task. This must be a multi-thread program, because it can be asked for running many tasks, and can be asked for the status of each task. The program only finishes when the last task is ended. 3) The client calss a getProcStatus(ID) method. The server, using IPC or Pipes, asks the already-launched process for its status. Regards, -- Leonardo M. Ramé http://leonardorame.blogspot.com -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] fpWeb long process progress
On Mon, Aug 13, 2012 at 7:31 PM, Leonardo M. Ramé l.r...@griensu.com wrote: On 2012-08-13 15:15:56 -0700, leledumbo wrote: How can I send responses by intervals? AFAIK that's not the way web application works. It's the client that should be querying the server in a regular interval (using AJAX request perhaps). The server can track current progress status and return that right away when asked. Yes, I know that, but I thought Lazarus have something easy to develop such process. The way I'm thinking of implementing is this: 1) The client app asks the server (a CGI process) for a process ID, for example 123, by calling getProcId. 2) Using this ID, the client calls the time-consuming task, passing the ID. for example, runTask(Id). At this time, the server launches a program passing the ID for the task. This must be a multi-thread program, because it can be asked for running many tasks, and can be asked for the status of each task. The program only finishes when the last task is ended. 3) The client calss a getProcStatus(ID) method. The server, using IPC or Pipes, asks the already-launched process for its status. Your program is the main thread. For each request your program should create a new thread to process. Each thread synchronizes with the main thread (your program) about it your own status. Already exists an example with the same idea (more or less)... in Pascal... called ExtPascal. Marcos Douglas -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
