So, I started learning to code in Python and later Django. The first times it was hard looking at tracebacks and actually figure out what I did wrong and where the syntax error was. Some time has passed now and some way along the way, I guess I got a routine in debugging my Django code. As this was done early in my coding experience, I sat down and wondered if how I was doing this was ineffective and could be done faster. I usually manage to find and correct the bugs in my code, but I wonder if I should be doing it faster?

我通常只使用Django启用时提供的调试信息。当事情确实像我想象的那样结束时,我用一个语法错误破坏了代码流,并查看流中那个点的变量,以找出代码在哪里做了与我想要的不同的事情。

但这种情况还能改善吗?是否有一些更好的工具或方法来调试Django代码?


当前回答

有很多方法可以做到这一点,但最直接的是简单 使用Python调试器。只需在Django视图函数中添加如下一行:

import pdb; pdb.set_trace()

or

breakpoint()  #from Python3.7

如果您试图在浏览器中加载该页,浏览器将挂起,并提示您对实际执行的代码进行调试。

但是也有其他的选择(我不推荐):

* return HttpResponse({variable to inspect})

* print {variable to inspect}

* raise Exception({variable to inspect})

但是对于所有类型的Python代码,强烈推荐使用Python调试器(pdb)。如果您已经开始使用pdb,那么您还需要了解使用ipython进行调试的IPDB。

对pdb有一些更有用的扩展

pdb++,由Antash建议。

pudb,由PatDuJour建议。

在Django中使用Python调试器,由Seafangs建议。

其他回答

另外一个建议。

您可以同时利用nosetests和pdb,而不是手动在视图中注入pdb.set_trace()。这样做的好处是,您可以在错误条件第一次启动时观察到它们,可能是在第三方代码中。

这是我今天的一个错误。

TypeError at /db/hcm91dmo/catalog/records/

render_option() argument after * must be a sequence, not int

....


Error during template rendering

In template /opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/crispy_forms/templates/bootstrap3/field.html, error at line 28
render_option() argument after * must be a sequence, not int
18  
19          {% if field|is_checkboxselectmultiple %}
20              {% include 'bootstrap3/layout/checkboxselectmultiple.html' %}
21          {% endif %}
22  
23          {% if field|is_radioselect %}
24              {% include 'bootstrap3/layout/radioselect.html' %}
25          {% endif %}
26  
27          {% if not field|is_checkboxselectmultiple and not field|is_radioselect %}
28  

      {% if field|is_checkbox and form_show_labels %}

现在,我知道这意味着我把表单的构造函数弄糊涂了,我甚至很清楚哪个字段有问题。但是,我可以使用pdb看到脆皮的形式是抱怨,在一个模板?

是的,我会。在nosetests上使用——pdb选项:

测试$ nosetests test_urls_catalog.py——pdb

一旦我碰到任何异常(包括优雅地处理的异常),pdb就会停止,我可以四处查看。

  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/forms/forms.py", line 537, in __str__
    return self.as_widget()
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/forms/forms.py", line 593, in as_widget
    return force_text(widget.render(name, self.value(), attrs=attrs))
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/forms/widgets.py", line 513, in render
    options = self.render_options(choices, [value])
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/forms/widgets.py", line 543, in render_options
    output.append(self.render_option(selected_choices, *option))
TypeError: render_option() argument after * must be a sequence, not int
INFO lib.capture_middleware log write_to_index(http://localhost:8082/db/hcm91dmo/catalog/records.html)
INFO lib.capture_middleware log write_to_index:end
> /opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/django/forms/widgets.py(543)render_options()
-> output.append(self.render_option(selected_choices, *option))
(Pdb) import pprint
(Pdb) pprint.PrettyPrinter(indent=4).pprint(self)
<django.forms.widgets.Select object at 0x115fe7d10>
(Pdb) pprint.PrettyPrinter(indent=4).pprint(vars(self))
{   'attrs': {   'class': 'select form-control'},
    'choices': [[('_', 'any type'), (7, (7, 'type 7', 'RECTYPE_TABLE'))]],
    'is_required': False}
(Pdb)         

现在,很明显,我对crispy field构造函数的choices参数是一个列表中的列表,而不是元组中的list/tuple。

 'choices': [[('_', 'any type'), (7, (7, 'type 7', 'RECTYPE_TABLE'))]]

整洁的事情是,这个pdb发生在脆皮的代码,而不是我的,我不需要手动插入它。

我强烈建议使用PDB。

import pdb
pdb.set_trace()

您可以检查所有变量值,进入函数和更多。 https://docs.python.org/2/library/pdb.html

用于检查对数据库的各种请求、响应和命中。我正在使用django-debug-toolbar https://github.com/django-debug-toolbar/django-debug-toolbar

从我的角度来看,我们可以将常见的代码调试任务分解为三种不同的使用模式:

Something has raised an exception: runserver_plus' Werkzeug debugger to the rescue. The ability to run custom code at all the trace levels is a killer. And if you're completely stuck, you can create a Gist to share with just a click. Page is rendered, but the result is wrong: again, Werkzeug rocks. To make a breakpoint in code, just type assert False in the place you want to stop at. Code works wrong, but the quick look doesn't help. Most probably, an algorithmic problem. Sigh. Then I usually fire up a console debugger PuDB: import pudb; pudb.set_trace(). The main advantage over [i]pdb is that PuDB (while looking as you're in 80's) makes setting custom watch expressions a breeze. And debugging a bunch of nested loops is much simpler with a GUI.

啊,是的,模板的问题。最常见的问题(对我和我的同事来说)是错误的上下文:要么你没有变量,要么你的变量没有某些属性。如果你正在使用调试工具栏,只检查“模板”部分的上下文,或者,如果这还不够,在你的上下文填充后,在视图的代码中设置一个断点。

就这样。

调试Django代码的最佳选择之一是通过wdb: https://github.com/Kozea/wdb

wdb works with python 2 (2.6, 2.7), python 3 (3.2, 3.3, 3.4, 3.5) and pypy. Even better, it is possible to debug a python 2 program with a wdb server running on python 3 and vice-versa or debug a program running on a computer with a debugging server running on another computer inside a web page on a third computer! Even betterer, it is now possible to pause a currently running python process/thread using code injection from the web interface. (This requires gdb and ptrace enabled) In other words it's a very enhanced version of pdb directly in your browser with nice features.

安装并运行服务器,并在代码中添加:

import wdb
wdb.set_trace()

作者认为,pdb的主要区别是:

For those who don’t know the project, wdb is a python debugger like pdb, but with a slick web front-end and a lot of additional features, such as: Source syntax highlighting Visual breakpoints Interactive code completion using jedi Persistent breakpoints Deep objects inspection using mouse Multithreading / Multiprocessing support Remote debugging Watch expressions In debugger code edition Popular web servers integration to break on error In exception breaking during trace (not post-mortem) in contrary to the werkzeug debugger for instance Breaking in currently running programs through code injection (on supported systems)

它有一个很棒的基于浏览器的用户界面。一种使用的乐趣!:)

调试python的最简单的方法——尤其是对习惯于Visual Studio的程序员来说——是使用PTVS (python Tools for Visual Studio)。 步骤很简单:

从https://microsoft.github.io/PTVS/下载并安装它 设置断点并按F5。 您的断点被击中,您可以查看/更改变量,就像调试c# / c++程序一样简单。 这就是全部:)

如果你想使用PTVS调试Django,你需要做以下事情:

在Project settings - General选项卡中,将“Startup File”设置为“manage.py”,这是Django程序的入口点。 在“项目设置-调试”选项卡中,将“脚本参数”设置为“runserver—noreload”。这里的关键点是“—noreload”。如果你不设置它,你的断点就不会被击中。 享受它。