Line data    Source code

       1             : // Snap Websites Servers -- check the MIME type of a file using the magic database
       2             : // Copyright (c) 2013-2019  Made to Order Software Corp.  All Rights Reserved
       3             : //
       4             : // This program is free software; you can redistribute it and/or modify
       5             : // it under the terms of the GNU General Public License as published by
       6             : // the Free Software Foundation; either version 2 of the License, or
       7             : // (at your option) any later version.
       8             : //
       9             : // This program is distributed in the hope that it will be useful,
      10             : // but WITHOUT ANY WARRANTY; without even the implied warranty of
      11             : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      12             : // GNU General Public License for more details.
      13             : //
      14             : // You should have received a copy of the GNU General Public License
      15             : // along with this program; if not, write to the Free Software
      16             : // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
      17             : 
      18             : // self
      19             : //
      20             : #include    "edhttp/mime_type.h"
      21             : 
      22             : #include    "edhttp/exception.h"
      23             : 
      24             : 
      25             : // C lib
      26             : //
      27             : #include    <magic.h>
      28             : 
      29             : 
      30             : // last include
      31             : //
      32             : #include    <snapdev/poison.h>
      33             : 
      34             : 
      35             : 
      36             : namespace edhttp
      37             : {
      38             : 
      39             : namespace
      40             : {
      41             : magic_t         g_magic = nullptr;
      42             : }
      43             : 
      44             : 
      45             : /** \brief Generate a MIME type from a buffer.
      46             :  *
      47             :  * This function determines the MIME type of a buffer (std::string)
      48             :  * using the magic library. The magic library is likely to
      49             :  * understand all the files that a user is to upload on a
      50             :  * website (within reason, of course).
      51             :  *
      52             :  * This function runs against the specified buffer (\p data) from
      53             :  * memory.
      54             :  *
      55             :  * The function returns the computed MIME type such as text/html or
      56             :  * image/png.
      57             :  *
      58             :  * \note
      59             :  * Compressed files get their type determined after decompression.
      60             :  *
      61             :  * \exception mime_type_no_magic
      62             :  * The function generates an exception if it cannot access the
      63             :  * magic library (the magic_open() function fails). If the magic
      64             :  * library is available but the type of the buffer can't be
      65             :  * determine, then a default MIME type is returned.
      66             :  *
      67             :  * \param[in] data  The buffer to be transformed in a MIME type.
      68             :  *
      69             :  * \return The MIME type of the input buffer.
      70             :  */
      71           0 : std::string get_mime_type(std::string const & data)
      72             : {
      73           0 :     if(g_magic == nullptr)
      74             :     {
      75           0 :         g_magic = magic_open(MAGIC_COMPRESS | MAGIC_MIME);
      76           0 :         if(g_magic == nullptr)
      77             :         {
      78           0 :             throw mime_type_no_magic("Magic MIME type cannot be opened (magic_open() failed)");
      79             :         }
      80             : 
      81             :         // load the default magic database
      82             :         //
      83           0 :         magic_load(g_magic, nullptr);
      84             :     }
      85             : 
      86           0 :     return magic_buffer(g_magic, data.data(), data.length());
      87             : }
      88             : 
      89             : 
      90             : 
      91             : } // namespace edhttp
      92             : // vim: ts=4 sw=4 et