在 Django 开发中,当发生错误时,定位问题所在的文件和代码行是调试的重要步骤。以下是一些常用的方法和技巧来定位导致 Django 错误的文件:
1、问题背景
在项目中使用了 shrink 工具尝试运行 collect static 时,出现 TemplateSyntaxError 错误。错误信息为 "Invalid filter: 'add_class'"。回溯信息中显示的所有文件都是 site-package 文件,并且对于错误来自何处感到困惑。
错误回溯信息如下:
> You have requested to collect static files at the destination location
> as specified in your settings.
>
> This will overwrite existing files! Are you sure you want to do this?
>
> Type 'yes' to continue, or 'no' to cancel: yes
>
> 0 static files copied, 1249 unmodified. Traceback (most recent call
> last): File "tools/manage.py", line 16, in <module>
> execute_manager(settings) File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/core/management/__init__.py",
> line 459, in execute_manager
> utility.execute() File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/core/management/__init__.py",
> line 382, in execute
> self.fetch_command(subcommand).run_from_argv(self.argv) File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/core/management/base.py",
> line 196, in run_from_argv
> self.execute(*args, **options.__dict__) File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/core/management/base.py",
> line 232, in execute
> output = self.handle(*args, **options) File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/core/management/base.py",
> line 371, in handle
> return self.handle_noargs(**options) File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/shrink/management/commands/collectstatic.py",
> line 58, in handle_noargs
> templates.add(get_template(pjoin(dirpath, f))) File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/template/loader.py",
> line 145, in get_template
> template, origin = find_template(template_name) File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/template/loader.py",
> line 134, in find_template
> source, display_name = loader(name, dirs) File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/template/loader.py",
> line 42, in __call__
> return self.load_template(template_name, template_dirs) File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/template/loader.py",
> line 48, in load_template
> template = get_template_from_string(source, origin, template_name) File
> "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/template/loader.py",
> line 156, in get_template_from_string
> return Template(source, origin, name) File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/template/base.py",
> line 125, in __init__
> self.nodelist = compile_string(template_string, origin) File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/template/base.py",
> line 153, in compile_string
> return parser.parse() File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/template/base.py",
> line 267, in parse
> compiled_result = compile_func(self, token) File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/template/loader_tags.py",
> line 214, in do_extends
> nodelist = parser.parse() File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/template/base.py",
> line 267, in parse
> compiled_result = compile_func(self, token) File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/template/loader_tags.py",
> line 189, in do_block
> nodelist = parser.parse(('endblock',)) File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/template/base.py",
> line 246, in parse
> filter_expression = self.compile_filter(token.contents) File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/template/base.py",
> line 346, in compile_filter
> return FilterExpression(token, self) File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/template/base.py",
> line 557, in __init__
> filter_func = parser.find_filter(filter_name) File "/home/adam/pyprojects/trekadoo-web/venv/local/lib/python2.7/site-packages/django/template/base.py",
> line 352, in find_filter
> raise TemplateSyntaxError("Invalid filter: '%s'" % filter_name) django.template.base.TemplateSyntaxError: Invalid filter: 'add_class'
add_class is used hundreds of time throughout the project.
2、解决方案
方法 1:调试模式和断点
在该示例中,通过调试模式可以找到缺少 {% load widget_tweaks %}
的文件,添加该行代码后,错误得到解决。
方法 2:使用 Django 调试工具
方法 3:使用 PyCharm 等 IDE 工具
方法 4:使用模板调试器
{% load debug %}
{{ debug }}
标签的 HTML 代码,以查看导致错误的具体位置。方法 5:使用 Python 控制台
print()
语句来打印变量和值。代码例子:
# 方法 1:调试模式和断点
import pdb
def collectstatic():
# ...
# 设置断点
pdb.set_trace()
# ...
#
总结
定位 Django 错误的文件和代码行,可以采用以下步骤:
通过这些方法,可以快速找到导致错误的文件和具体行号,并有效修复问题。
原创声明:本文系作者授权腾讯云开发者社区发表,未经许可,不得转载。
如有侵权,请联系 cloudcommunity@tencent.com 删除。
原创声明:本文系作者授权腾讯云开发者社区发表,未经许可,不得转载。
如有侵权,请联系 cloudcommunity@tencent.com 删除。