tests/fetch/response_headers.cpp

// Copyright 2018 The Emscripten Authors.  All rights reserved.
// Emscripten is available under two separate licenses, the MIT license and the
// University of Illinois/NCSA Open Source License.  Both these licenses can be
// found in the LICENSE file.

#include <string.h>
#include <stdio.h>
#include <math.h>
#include <assert.h>
#include <emscripten/fetch.h>

int result = 0;

int main()
{
    static const char* const headers[] = {
        "X-Emscripten-Test",
        "1",
        0,
    };
    const size_t n_values = sizeof( headers ) / sizeof( headers[ 0 ] ) - 1;
    emscripten_fetch_attr_t attr;
    emscripten_fetch_attr_init( &attr );
    strcpy( attr.requestMethod, "GET" );
    attr.attributes = EMSCRIPTEN_FETCH_REPLACE | EMSCRIPTEN_FETCH_LOAD_TO_MEMORY | EMSCRIPTEN_FETCH_SYNCHRONOUS;
    attr.requestHeaders = headers;

    attr.onsuccess = [] ( emscripten_fetch_t *fetch )
    {
        assert( fetch->__attributes.requestHeaders != 0 );
        assert( fetch->__attributes.requestHeaders != headers );
        for ( size_t i = 0; i < n_values; ++i )
        {
            const char* origHeader = headers[ i ];
            const char* header = fetch->__attributes.requestHeaders[ i ];
            assert( origHeader != header );
            assert( strcmp( origHeader, header ) == 0 );
        }
        assert( fetch->__attributes.requestHeaders[ n_values ] == 0 );

        printf( "Finished downloading %llu bytes\n", fetch->numBytes );
        // Compute rudimentary checksum of data
        uint8_t checksum = 0;
        for ( int i = 0; i < fetch->numBytes; ++i )
            checksum ^= fetch->data[ i ];
        printf( "Data checksum: %02X\n", checksum );
        assert( checksum == 0x08 );
        emscripten_fetch_close( fetch );

        if ( result == 0 ) result = 1;
#ifdef REPORT_RESULT
        // Fetch API appears to sometimes call the handlers more than once, see https://github.com/emscripten-core/emscripten/pull/8191
        MAYBE_REPORT_RESULT(result);
#endif
    };

    attr.onprogress = [] ( emscripten_fetch_t *fetch )
    {
        if ( fetch->totalBytes > 0 )
        {
            printf( "Downloading.. %.2f%% complete.\n", ( fetch->dataOffset + fetch->numBytes ) * 100.0 / fetch->totalBytes );
        }
        else
        {
            printf( "Downloading.. %lld bytes complete.\n", fetch->dataOffset + fetch->numBytes );
        }
    };

    attr.onerror = [] ( emscripten_fetch_t *fetch )
    {
        printf( "Download failed!\n" );
        emscripten_fetch_close(fetch);
        assert( false && "Shouldn't fail!" );
    };

    emscripten_fetch_t *fetch = emscripten_fetch( &attr, "gears.png" );
    if ( result == 0 )
    {
        result = 2;
        printf( "emscripten_fetch() failed to run synchronously!\n" );
    }
#ifdef REPORT_RESULT
    // Fetch API appears to sometimes call the handlers more than once, see https://github.com/emscripten-core/emscripten/pull/8191
    MAYBE_REPORT_RESULT(result);
#endif
}