Changes between Version 64 and Version 65 of DeveloperGuidelines/CodeConventions

Timestamp:

01/20/18 21:34:14 (7 years ago)

Author:

Dominic König

Comment:

--

DeveloperGuidelines/CodeConventions

@@ -28 +28 @@
 === Print Statements ===
 
-For compatibility with WSGI as well as newer web2py (>=2.15), using the {{{print}}} statement in web application sources is strongly discouraged.
-
-CLI scripts containing print statements will even crash since gluon/shell.py now future-imports the Python-3 print_function.
+For compatibility with WSGI as well as newer web2py (>=2.15), using the {{{print}}} statement in web application sources is '''strongly discouraged'''.
+
+CLI scripts containing print statements will even '''crash''' since gluon/shell.py now future-imports the {{{print()}}}-function.
 
 For everything that is to be executed in the restricted environment (i.e. all server code):
- - use sys.stderr.write()
- - better yet (and mandatory for any permanent debug/error messages): use {{{current.log.*}}}, as it can be turned on/off centrally, and routed to a log file
- - if absolutely necessary, add the future-import to the file and use the print-function
+ - for messages explaining mandatory crashes that prevent the system from running at all (e.g. mandatory module import failures), use {{{sys.stderr.write()}}}
+ - for all other permanent debug/error messages: use {{{current.log.*}}}, as it can be controlled on/off centrally, and routed to a log file when web2py isn't console-run
+ - for temporary debug output in code under development, use {{{sys.stderr.write()}}}
+ - if absolutely necessary (re-think your design!), add the future-import to the file and use the print-''function''
 
 For CLI scripts:
- - use sys.stderr.write() for status/error messages, or sys.stdout.write() for results
+ - use {{{sys.stderr.write()}}} for status/error messages, or {{{sys.stdout.write()}}} for results
  - alternatively, add the future-import to the script and use the print-function
 
-Using {{{sys.std*.write()}}} (remember that write expects string/bugger, so must convert explicitly):
+Using {{{sys.std*.write()}}} (remember that write expects string/buffer, so you must convert any parameters explicitly):
 {{{#!python
 import sys
@@ -56 +57 @@
 from gluon import current
 
-# Use this for any permanent message output in server scripts:
+# Use this for any permanent message output in server code:
 current.log.error("Here is an error message")
+
+current.log.debug("And this is a debug message")
 }}}
 
@@ -71 +74 @@
 print("Direct output to stderr", file=sys.stderr)
 }}}
-
 === Quotes ===