Backslashes in template tag arguments are escaped

[bhch]

I've written a custom template tag to replace parts of a value:

@register.simple_tag
def string_replace(value, old, new):
    return value.replace(old, new)

And I'm using it to replace newline characters with commas in a user's address:

{% string_replace user.address '\r\n'  ',' %}

However, this doesn't work.

The reason is that when Django loads a template using Python's file.read() function, the backslashes get escaped which means \r\n becomes \\r\\n.

So, the string_replace tag actually receives \\r\\n instead of \r\n. This also affects other tags as well.

Shouldn't Django pass the original string argument to the template tag as intended?

[Mariusz Felisiak]

Thanks for the report, however I don't think Django can do much here, and any change would be backward incompatible. Please also take into account that it works when value is passed directly, e.g.

{% string_replace "My address\r\nwith newline characters" "\r\n"  "," %}

I'd recommend to create a new filter, e.g. {% replace_newline value %}, pass arguments via context variables, or escape/unescape arguments in string_replace().