Re: [Twisted-web] Asynchronous responses example from documentation -- why import time??
On Wed, 8 Aug 2018 at 11:58 AM Jean-Paul Calderone < exarkun@twistedmatrix.com> wrote:
One possible explanation is that it has nothing to do with import time per
se. Instead, *any* change to your source file would have fixed the problem. This could be because you had "stale" pyc files lying around (cached bytecode the interpreter *thought* was up-to-date with your source but was actually outdated). It could also be that your server process was left running and was still using your old code. Then, for some reason, after you added the import time your server got the new version of the code (perhaps you're relying on an auto-reloader and it missed a change, for example, or you just forgot to restart the server yourself).
import time itself is definitely not a requirement for arbitrary Twisted Web-based programs to return a response other than 404.
Jean-Paul
Hi Jean-Paul, I made many changes to the example in order to get it to work. So perhaps it's a caching issue, but I can't find any caches. Here's what I'm developing on: - OSX 10.13.6 - I'm using Sublime text, no auto reloaders afaik - python3 --version : Python 3.7.0 - pip3 list: Package Version -------------- ------- attrs 18.1.0 Automat 0.7.0 constantly 15.1.0 dlib 19.15.0 hyperlink 18.0.0 idna 2.7 incremental 17.5.0 numpy 1.15.0 pip 18.0 PyHamcrest 1.9.0 setuptools 39.2.0 six 1.11.0 Twisted 18.7.0 wheel 0.31.1 zope.interface 4.5.0 - running the server using ./asynchronous.py - I don't have any .pyc files in the script directory, possibly because I "chmod +x" the source file and included the #! at the top - I added logging and while the main program (setup of Twisted reactor) logged, the DelayedResource class did not - I added parts of the example at https://twistedmatrix.com/documents/current/web/howto/web-in-60/dynamic-cont... - I changed "resource = DelayedResource()" to "resource = ClockPage()" - I changed the render_GET handler to return the Clock page example output - etc until I stopped getting a 404 - I restarted the server many many times I removed and backed out every change until I got a 404, concluding it was the "import time" line. Any other ideas?
I may have found it, by adding the assignment "isLeaf = True" to the DelayedResponse class it also appears to work. However many of the examples in the documentation do not assign "isLeaf = True". Would this also explain the difference in behaviour? -Jason Cell: 604 644 8611 Email: drjasonharrison@gmail.com LinkedIn: http://www.linkedin.com/in/drjasonharrison Twitter: http://twitter.com/drjasonharrison On Wed, Aug 8, 2018 at 1:19 PM, Jason Harrison <drjasonharrison@gmail.com> wrote:
On Wed, 8 Aug 2018 at 11:58 AM Jean-Paul Calderone <
exarkun@twistedmatrix.com> wrote:
One possible explanation is that it has nothing to do with import time per
se. Instead, *any* change to your source file would have fixed the problem. This could be because you had "stale" pyc files lying around (cached bytecode the interpreter *thought* was up-to-date with your source but was actually outdated). It could also be that your server process was left running and was still using your old code. Then, for some reason, after you added the import time your server got the new version of the code (perhaps you're relying on an auto-reloader and it missed a change, for example, or you just forgot to restart the server yourself).
import time itself is definitely not a requirement for arbitrary Twisted Web-based programs to return a response other than 404.
Jean-Paul
Hi Jean-Paul,
I made many changes to the example in order to get it to work. So perhaps it's a caching issue, but I can't find any caches. Here's what I'm developing on:
- OSX 10.13.6 - I'm using Sublime text, no auto reloaders afaik - python3 --version : Python 3.7.0 - pip3 list:
Package Version -------------- ------- attrs 18.1.0 Automat 0.7.0 constantly 15.1.0 dlib 19.15.0 hyperlink 18.0.0 idna 2.7 incremental 17.5.0 numpy 1.15.0 pip 18.0 PyHamcrest 1.9.0 setuptools 39.2.0 six 1.11.0 Twisted 18.7.0 wheel 0.31.1 zope.interface 4.5.0
- running the server using ./asynchronous.py - I don't have any .pyc files in the script directory, possibly because I "chmod +x" the source file and included the #! at the top - I added logging and while the main program (setup of Twisted reactor) logged, the DelayedResource class did not - I added parts of the example at https://twistedmatrix.com/ documents/current/web/howto/web-in-60/dynamic-content.html - I changed "resource = DelayedResource()" to "resource = ClockPage()" - I changed the render_GET handler to return the Clock page example output - etc until I stopped getting a 404 - I restarted the server many many times
I removed and backed out every change until I got a 404, concluding it was the "import time" line. Any other ideas?
In the code you posted, DelayedResponse is the root resource. The root resource *always* has to provide a child resource. If someone requests /foo then the child is "foo". If someone requests "/" then the child is "". isLeaf = True is a shortcut that stops traversal and uses the current resource as the requested resource. Without this, DelayedResponse must have a child or it can only produce a 404. Maybe that explains it? If there are examples in the documentation that have root resources with no children and without isLeaf = True then perhaps they are also broken and should be fixed. If you see any, please point them out. Jean-Paul On Wed, Aug 8, 2018 at 4:47 PM Jason Harrison <drjasonharrison@gmail.com> wrote:
I may have found it, by adding the assignment "isLeaf = True" to the DelayedResponse class it also appears to work. However many of the examples in the documentation do not assign "isLeaf = True". Would this also explain the difference in behaviour?
-Jason
Cell: 604 644 8611 Email: drjasonharrison@gmail.com LinkedIn: http://www.linkedin.com/in/drjasonharrison Twitter: http://twitter.com/drjasonharrison
On Wed, Aug 8, 2018 at 1:19 PM, Jason Harrison <drjasonharrison@gmail.com> wrote:
On Wed, 8 Aug 2018 at 11:58 AM Jean-Paul Calderone <
exarkun@twistedmatrix.com> wrote:
One possible explanation is that it has nothing to do with import time per
se. Instead, *any* change to your source file would have fixed the problem. This could be because you had "stale" pyc files lying around (cached bytecode the interpreter *thought* was up-to-date with your source but was actually outdated). It could also be that your server process was left running and was still using your old code. Then, for some reason, after you added the import time your server got the new version of the code (perhaps you're relying on an auto-reloader and it missed a change, for example, or you just forgot to restart the server yourself).
import time itself is definitely not a requirement for arbitrary Twisted Web-based programs to return a response other than 404.
Jean-Paul
Hi Jean-Paul,
I made many changes to the example in order to get it to work. So perhaps it's a caching issue, but I can't find any caches. Here's what I'm developing on:
- OSX 10.13.6 - I'm using Sublime text, no auto reloaders afaik - python3 --version : Python 3.7.0 - pip3 list:
Package Version -------------- ------- attrs 18.1.0 Automat 0.7.0 constantly 15.1.0 dlib 19.15.0 hyperlink 18.0.0 idna 2.7 incremental 17.5.0 numpy 1.15.0 pip 18.0 PyHamcrest 1.9.0 setuptools 39.2.0 six 1.11.0 Twisted 18.7.0 wheel 0.31.1 zope.interface 4.5.0
- running the server using ./asynchronous.py - I don't have any .pyc files in the script directory, possibly because I "chmod +x" the source file and included the #! at the top - I added logging and while the main program (setup of Twisted reactor) logged, the DelayedResource class did not - I added parts of the example at https://twistedmatrix.com/documents/current/web/howto/web-in-60/dynamic-cont... - I changed "resource = DelayedResource()" to "resource = ClockPage()" - I changed the render_GET handler to return the Clock page example output - etc until I stopped getting a 404 - I restarted the server many many times
I removed and backed out every change until I got a 404, concluding it was the "import time" line. Any other ideas?
_______________________________________________ Twisted-web mailing list Twisted-web@twistedmatrix.com https://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-web
participants (2)
-
Jason Harrison -
Jean-Paul Calderone