/* * Name: get_http_tile.c * * Description: * This is a CGI program that reads a single tile from a localdisk * dataset and returns it as raw data or as a JFIF/JPEG file. This * program should be installed in the cgi-bin directory of the http * server to enable external clients to read datasets via http. * * See the function InvalidArgs() for the CGI URL syntax. * * This program requires the libcgi.a library. * * This program was written for use with the tsmApi library from * SRI International. For further information about this library, * including downloads, documentation, and other examples, see: * * http://www.tsmApi.com/ * * Author: * Martin Reddy, - 7 December 1998. * * Function List: * void usage( void ) * int main( int, char** ) * * Revision Information: * * $Id: get_http_tile.c,v 1.5 2000/08/28 23:56:01 reddy Exp $ * * License: * The contents of this file are subject to the Open Source Apache * Software License Version 1.1 (the "License"); you may not use * this file except in compliance with the License. You may obtain a * copy of the License at http://www.tsmapi/license.shtml. * * Software distributed under the License is distributed on an "AS IS" * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the * License for the specific language governing rights and limitations * under the License. * * Portions are Copyright (c) SRI International, 1998-2000. */ #include #include #include #include /* N.B. pyramid_dir may need to be customised for a local system */ static char *pyramid_dir = "/homedir/magic/TileSets/Pyramids"; /* static char *pyramid_dir = "/home/g2/users/reddy/public_html/TileSets/Pyramids"; */ static char *pyramid_name = NULL; static char *tile_x = NULL; static char *tile_y = NULL; static char *tile_level = NULL; static char *tile_test = NULL; static char *tile_info = NULL; static TsmConnectionParams params; void InvalidArgs( form_entry *p ) { print_mimeheader("text/html"); puts( "

" );
  puts( "Program: get_http_tile" );
  printf( "Version: %s\n", tsmCvsToString( "$Revision: 1.5 $" ) );
  puts( "Purpose: reads a single tile from a TIFF file via http" );
  puts( "Usage: /cgi-bin/get_http_tile?" );
  puts( "          pyramid=[pyramid-name]    % name of pyramid, e.g. co.dem" );
  puts( "          x=[x]                     % x coordinate for tile" );
  puts( "          y=[y]                     % y coordinate for tile" );
  puts( "          level=[level]             % level number for tile" );
  puts( "          dir=[dir]                 % localdisk dir for Pyramids" );
  puts( "          lrbt=yes                  % use raw raster tiles" );
  puts( "          jpeg=yes                  % use jpeg compressed tiles" );
  puts( "          lzw=yes                   % use lzw compressed tiles" );
  puts( "          tiffs=yes                 % use TIFF format imagery" );
  puts( "          rawtiles=yes              % use raw .tile format imagery" );
  puts( "          test=yes                  % display tile in browser" );
  puts( "          info=yes                  % output tile info, no data" );
  printf( "Localdisk Pyramid dir: %s\n", pyramid_dir );
  puts( "Your args were:" );

  if ( p ) {
    for( ; p; p = p->next )
      printf( "  %s = %s\n", p->name, p->val );
  } else
    puts( "  None" );
  
  puts( "

" ); exit( 0 ); } void GetTileError( char *message ) { print_mimeheader("text/html"); printf( "

\n%s\n

\n", message ); exit( 0 ); } void ParseArgs( void ) { int i; cgi_info ci; form_entry *parms, *p; /* Read the CGI parameters */ get_cgi_info (&ci); if ( ( parms = get_form_entries(&ci) ) == NULL ) InvalidArgs( parms ); /* Parse out the params we require */ for( p=parms; p; p = p->next ) { /* Required settings */ if ( ! strcasecmp( p->name, "pyramid" ) ) pyramid_name = p->val; else if ( ! strcasecmp( p->name, "x" ) ) tile_x = p->val; else if ( ! strcasecmp( p->name, "y" ) ) tile_y = p->val; else if ( ! strcasecmp( p->name, "level" ) ) tile_level = p->val; /* Optional settings */ else if ( ! strcasecmp( p->name, "test" ) ) tile_test = p->val; else if ( ! strcasecmp( p->name, "info" ) ) tile_info = p->val; else if ( ! strcasecmp( p->name, "dir" ) ) pyramid_dir = p->val; else if ( ! strcasecmp( p->name, "lrbt" ) ) tsmSetParam( params, TSM_PARAM_FORMAT, TSM_LRBT_FORMAT ); else if ( ! strcasecmp( p->name, "jpeg" ) ) tsmSetParam( params, TSM_PARAM_FORMAT, TSM_JPEG_FORMAT ); else if ( ! strcasecmp( p->name, "lzw" ) ) tsmSetParam( params, TSM_PARAM_FORMAT, TSM_LZW_FORMAT ); else if ( ! strcasecmp( p->name, "tiffs" ) ) tsmSetParam( params, TSM_PARAM_TIFF, TRUE ); else if ( ! strcasecmp( p->name, "rawtiles" ) ) tsmSetParam( params, TSM_PARAM_TIFF, FALSE ); } /* Check that we have all required params */ if ( pyramid_name == NULL || tile_x == NULL || tile_y == NULL || tile_level == NULL ) InvalidArgs( parms ); } #include #include void OutputTimestamp( char *comment ) { #if 0 struct timeval tp; time_t clock; struct tm *localtm; char *timestr = ""; clock = time(NULL); if ( ( localtm = localtime( &clock ) ) != NULL ) { timestr = asctime( localtm ); timestr[24] = '\0'; } fprintf( stderr, "get_http_tile: %s - %s\n", timestr, comment ); #else struct timeval tp; double this_clock; static double last_clock = 0, first_clock = 0; char timestr[128]; gettimeofday( &tp, NULL ); this_clock = (double) tp.tv_sec + ( tp.tv_usec / 1e6 ); if ( last_clock == 0 ) { strcpy( timestr, "T=0 sec" ); first_clock = this_clock; } else sprintf( timestr, "T+%1.3lf: %1.3lf sec later", this_clock - first_clock, this_clock - last_clock ); last_clock = this_clock; #endif fprintf( stderr, "get_http_tile: %s - %s\n", timestr, comment ); } #define JFIF_MAGIC_SIZE 20 /* the byte size of the JFIF file header */ void WriteTileAsJFIF( TsmConnection connect, uchar *tileBuffer ) { uchar *jpegBuffer = tsmAllocTileBuffer( connect ); Pyramid *tspec = (Pyramid *) tsmGet( connect, TSM_DATASET_TSPEC ); static const int offset = JFIF_MAGIC_SIZE - 2; /* +header, -M_SOI marker */ int length; /* store the JFIF header section in a static array for quick access */ static unsigned char jfif_header[JFIF_MAGIC_SIZE] = { 0xff, 0xD8, /* M_SOI marker */ 0xFF, 0xE0, 0x00, 0x10, /* M_APP0 marker and length */ 'J', 'F', 'I', 'F', '\0', /* JFIF identifier */ 0x01, 0x02, /* JFIF version = 1.02 */ 0x00, /* units = none */ 0x00, 0x01, 0x00, 0x01, /* x and y densities = 1 */ 0x00, 0x00 /* no thumbnail image */ }; /* Compress the tile into the jpeg buffer (leaving room for header) */ length = tsmJPEGCompressTile( tileBuffer, jpegBuffer + offset, &tspec->tileTspec, 75 ); if ( length == 0 ) { tsmFreeTileBuffer( jpegBuffer ); tsmDisconnect( connect ); GetTileError( "Couldn't JPEG compress the given tile" ); } /* Write the JFIF APP header to the start of the jpeg buffer */ memcpy( jpegBuffer, jfif_header, JFIF_MAGIC_SIZE ); print_mimeheader("image/jpeg"); fwrite( jpegBuffer, 1, length + offset, stdout ); tsmFreeTileBuffer( jpegBuffer ); } int main( int argc, char **argv ) { TsmConnection connect; char filename[512], msg[512]; uchar *tileBuffer; int tx, ty, level; OutputTimestamp( "begin request" ); /* Parse all of the CGI parameters */ tsmInitParams( ¶ms ); ParseArgs(); tx = atoi( tile_x ); ty = atoi( tile_y ); level = atoi( tile_level ); /* Open a connection to the pyramid dataset */ sprintf( filename, "%s/%s", pyramid_dir, pyramid_name ); OutputTimestamp( "connect to dataset" ); if ( ( connect = tsmConnect( filename, "r", params ) ) == NULL ) { tsmFreeParams( params ); sprintf( msg, "Could not connect to pyramid: %s", filename ); GetTileError( msg ); } tsmFreeParams( params ); /* Now get the requested tile */ OutputTimestamp( "read the tile" ); if ( tsmAllocReadTile( connect, tx, ty, level, &tileBuffer ) == FALSE ) { tsmDisconnect( connect ); sprintf( msg, "Could not read tile: %d, %d, %d", tx, ty, level ); GetTileError( msg ); } OutputTimestamp( "serve the tile" ); /* Now output the tile as the result of this cgi request */ if ( tile_test != NULL ) WriteTileAsJFIF( connect, tileBuffer ); else if ( tile_info != NULL ) { print_mimeheader("text/html"); puts( "

" );
    tsmDescribeConnection( connect );
    puts( "

" ); } else { print_mimeheader("text/html"); fwrite( tileBuffer, 1, tsmGet( connect, TSM_TILE_SIZE ), stdout ); } /* All done now */ OutputTimestamp( "end request" ); tsmFreeTileBuffer( tileBuffer ); tsmDisconnect( connect ); OutputTimestamp( "done" ); return 0; }