GeoTiffTransmitter.cc

// GeoTiffTransmitter.cc
 
// This file is part of BES GDAL File Out Module
 
// Copyright (c) 2012 OPeNDAP, Inc.
// Author: James Gallagher <jgallagher@opendap.org>
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//
// You can contact University Corporation for Atmospheric Research at
// 3080 Center Green Drive, Boulder, CO 80301
 
#include "config.h"
 
#include <unistd.h>
 
#include <cstdio>
#include <cstdlib>
 
#include <sys/types.h>                  // For umask
#include <sys/stat.h>
 
#include <iostream>
#include <fstream>
 
#include <libdap/DataDDS.h>
#include <libdap/BaseType.h>
#include <libdap/escaping.h>
 
#include <dispatch/BESUtil.h>
#include <dispatch/BESInternalError.h>
#include <dispatch/BESContextManager.h>
#include <dispatch/BESDataNames.h>
#include <dispatch/BESDebug.h>
#include <dispatch/RequestServiceTimer.h>
#include <dispatch/TheBESKeys.h>
 
#include <dap/BESDapError.h>
#include <dap/BESDataDDSResponse.h>
#include <dap/BESDapNames.h>
#include <dap/DapFunctionUtils.h>
#include <dap/TempFile.h>
 
#include "GeoTiffTransmitter.h"
#include "FONgTransform.h"
 
#define FONG_TEMP_DIR "/tmp"
#define FONG_GCS "WGS84"
#define MODULE "gdal"
#define prolog string("GeoTiffTransmitter::").append(__func__).append("() - ")
 
using namespace libdap;
using namespace std;
 
string GeoTiffTransmitter::temp_dir;
string GeoTiffTransmitter::default_gcs;

GeoTiffTransmitter::GeoTiffTransmitter() :  BESTransmitter()
{
    // DATA_SERVICE == "dods"
    add_method(DATA_SERVICE, GeoTiffTransmitter::send_data_as_geotiff);
 
    if (GeoTiffTransmitter::temp_dir.empty()) {
        // Where is the temp directory for creating these files
        bool found = false;
        string key = "FONg.Tempdir";
        TheBESKeys::TheKeys()->get_value(key, GeoTiffTransmitter::temp_dir, found);
        if (!found || GeoTiffTransmitter::temp_dir.empty()) {
            GeoTiffTransmitter::temp_dir = FONG_TEMP_DIR;
        }
        string::size_type len = GeoTiffTransmitter::temp_dir.size();
        if (GeoTiffTransmitter::temp_dir[len - 1] == '/') {
            GeoTiffTransmitter::temp_dir = GeoTiffTransmitter::temp_dir.substr(0, len - 1);
        }
    }
 
    if (GeoTiffTransmitter::default_gcs.empty()) {
        // Use what as the default Geographic coordinate system?
        bool found = false;
        string key = "FONg.Default_GCS";
        TheBESKeys::TheKeys()->get_value(key, GeoTiffTransmitter::default_gcs, found);
        if (!found || GeoTiffTransmitter::default_gcs.empty()) {
            GeoTiffTransmitter::default_gcs = FONG_GCS;
        }
    }
}

void GeoTiffTransmitter::send_data_as_geotiff(BESResponseObject *obj, BESDataHandlerInterface &dhi)
{
    BESDataDDSResponse *bdds = dynamic_cast<BESDataDDSResponse *>(obj);
    if (!bdds)
        throw BESInternalError("cast error", __FILE__, __LINE__);
 
    DDS *dds = bdds->get_dds();
    if (!dds)
        throw BESInternalError("No DataDDS has been created for transmit", __FILE__, __LINE__);
 
    ostream &strm = dhi.get_output_stream();
    if (!strm)
        throw BESInternalError("Output stream is not set, cannot return as", __FILE__, __LINE__);
 
    BESDEBUG(MODULE, "GeoTiffTransmitter::send_data - parsing the constraint" << endl);
 
    // ticket 1248 jhrg 2/23/09
    string ce = www2id(dhi.data[POST_CONSTRAINT], "%", "%20%26");
    try {
        bdds->get_ce().parse_constraint(ce, *dds);
    }
    catch (const Error &e) {
        throw BESDapError("Failed to parse the constraint expression: " + e.get_error_message(), false, e.get_error_code(), __FILE__, __LINE__);
    }
    catch (...) {
        throw BESInternalError("Failed to parse the constraint expression: Unknown exception caught", __FILE__, __LINE__);
    }
 
    // now we need to read the data
    BESDEBUG(MODULE, "GeoTiffTransmitter::send_data - reading data into DataDDS" << endl);
 
    try {
        // Handle *functional* constraint expressions specially
        if (bdds->get_ce().function_clauses()) {
            BESDEBUG(MODULE, "processing a functional constraint clause(s)." << endl);
            DDS *tmp_dds = bdds->get_ce().eval_function_clauses(*dds);
            delete dds;
            dds = tmp_dds;
            bdds->set_dds(dds);
 
            // This next step utilizes a well known function, promote_function_output_structures()
            // to look for one or more top level Structures whose name indicates (by way of ending
            // with "_uwrap") that their contents should be promoted (aka moved) to the top level.
            // This is in support of a hack around the current API where server side functions
            // may only return a single DAP object and not a collection of objects. The name suffix
            // "_unwrap" is used as a signal from the function to the the various response
            // builders and transmitters that the representation needs to be altered before
            // transmission, and that in fact is what happens in our friend
            // promote_function_output_structures()
            promote_function_output_structures(dds);
 
        }
        else {
            // Iterate through the variables in the DataDDS and read
            // in the data if the variable has the send flag set.
            for (DDS::Vars_iter i = dds->var_begin(); i != dds->var_end(); i++) {
                if ((*i)->send_p()) {
                    (*i)->intern_data(bdds->get_ce(), *dds);
                }
            }
        }
    }
    catch (const Error &e) {
        throw BESDapError("Failed to read data: " + e.get_error_message(), false, e.get_error_code(), __FILE__, __LINE__);
    }
    catch (const BESError &e) {
        throw;
    }
    catch (...) {
        throw BESInternalError("Failed to read data: Unknown exception caught", __FILE__, __LINE__);
    }
 
    // This closes the file when it goes out of scope. jhrg 8/25/17
    bes::TempFile temp_file;
    string temp_file_name = temp_file.create(GeoTiffTransmitter::temp_dir, "geotiff_");
 
    // transform the OPeNDAP DataDDS to the geotiff file
    BESDEBUG(MODULE, "GeoTiffTransmitter::send_data - transforming into temporary file " << temp_file_name << endl);
 
    try {
        FONgTransform ft(dds, bdds->get_ce(), temp_file_name);
 
        // Verify the request hasn't exceeded bes_timeout, and disable timeout if allowed.
        RequestServiceTimer::TheTimer()->throw_if_timeout_expired(prolog + "ERROR: bes-timeout expired before transmit", __FILE__, __LINE__);
        BESUtil::conditional_timeout_cancel();
 
        // transform() opens the temporary file, dumps data to it and closes it.
        ft.transform_to_geotiff();
 
        BESDEBUG(MODULE, "GeoTiffTransmitter::send_data - transmitting temp file " << temp_file_name << endl );
 
        GeoTiffTransmitter::return_temp_stream(temp_file_name, strm);
    }
    catch (const Error &e) {
        throw BESDapError("Failed to transform data to GeoTiff: " + e.get_error_message(), false, e.get_error_code(), __FILE__, __LINE__);
    }
    catch (const BESError &e) {
        throw;
    }
    catch (...) {
        throw BESInternalError("Fileout GeoTiff, was not able to transform to geotiff, unknown error", __FILE__, __LINE__);
    }
 
    BESDEBUG(MODULE, "GeoTiffTransmitter::send_data - done transmitting to geotiff" << endl);
}

void GeoTiffTransmitter::return_temp_stream(const string &filename, ostream &strm)
{
    ifstream os;
    os.open(filename.c_str(), ios::binary | ios::in);
    if (!os)
        throw BESInternalError("Cannot connect to data source", __FILE__, __LINE__);
 
    char block[4096];
    os.read(block, sizeof block);
    int nbytes = os.gcount();
    if (nbytes == 0) {
        os.close();
        throw BESInternalError("Internal server error, got zero count on stream buffer.", __FILE__, __LINE__);
    }
 
    // I think this is never used - we never run Hyrax where the BES is accessed
    // directly by HTTP.
    bool found = false;
    string protocol = BESContextManager::TheManager()->get_context("transmit_protocol", found);
    if (protocol == "HTTP") {
        strm << "HTTP/1.0 200 OK\n";
        strm << "Content-type: application/octet-stream\n";
        strm << "Content-Description: " << "BES dataset" << "\n";
        strm << "Content-Disposition: filename=" << filename << ".tif;\n\n";
        strm << flush;
    }
 
    strm.write(block, nbytes);
 
    while (os) {
        os.read(block, sizeof block);
        nbytes = os.gcount();
        strm.write(block, nbytes);
    }
 
    os.close();
}