Re: [Cppcms-users] undefined reference to `cppcms::widgets::file::filename(booster::regex const&)'

[Artyom <art...@ya...>]

> BTW, there are some better tests for checking file type: mime() type and 
>add_valid_magic() where the last is the best
>one.
>
>
>
>Thank you for the enlightenment! According to 
>
>
>http://www.garykessler.net/library/file_sigs.html
>
>
>, the jpeg magic number is "FF D8 FF E0 xx xx 4A 46 49 46 00" and the png one is 
>
>"89 50 4E 47 0D 0A 1A 0A".
>
>
>
>Member function
>
>
>void cppcms::widgets::file::add_valid_magic(std::string const &) 
>
>
>expects std::string as the argument. If I accept both jpeg and png files, what 
>std::string should I pass to add_valid_magic?

You should call add_valid_magic twice and for one provide a valid magic:

For jpeg, is is enough to give "\xFF\xD8\xFF" (see more detailed description in 
the link you had given)
and for PNG "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A"

>
>
>This raises another question: It is server's responsibility rather than browsers 
>
>to perform the validation triggered by add_valid_magic, isn't it?

Of course it is the server side check, quite simple - test of file begins with 
this string - that's it.

> If it is, will 
> cppcms automatically do the validation? 

Yes, when you call your_form.validate() (as you usually do for forms) you'll get 
the validation
result. Each widget has its own set of parameters to validate.
 
> If it is programmer's job, a snippet of 
> validation example code will be much appreciated.
>

See forms example (you had probably seen it) and refer to each widget reference
to see validation options:

http://cppcms.sourceforge.net/cppcms_ref_v0_99/namespacecppcms_1_1widgets.html


Artyom