Truxton message get file - Revision history

Sam: /* Sample */

2021-04-03T13:58:33Z

Sample

Sam at 16:41, 9 February 2021

2021-02-09T16:41:46Z

Sam at 11:39, 6 February 2021

2021-02-06T11:39:35Z

Sam: /* Sample */

2020-12-11T22:44:06Z

Sample

Sam: /* Sample */

2020-12-11T22:40:12Z

Sample

Sam: /* Sample */

2020-12-11T22:39:23Z

Sample

Sam at 22:36, 11 December 2020

2020-12-11T22:36:16Z

Sam: Created page with "This will give you a barely functioning file object from the message. =Syntax= uint64_t truxton_message_get_file( uint64_t message_ha..."

2020-12-11T22:35:58Z

Created page with "This will give you a barely functioning file object from the message. =Syntax= <source lang="C"> uint64_t truxton_message_get_file( uint64_t message_ha..."

New page

This will give you a barely functioning [[Truxton C API#File|file]] object from the message.

=Syntax=
<source lang="C">
uint64_t truxton_message_get_file( uint64_t message_handle );
</source>

=Parameters=
==<code>message_handle</code>==
The handle created by the [[truxton_message_create]] or [[truxton_etl_get_message]] call.

=Return value=
The a [[Truxton C API#File|file]] handle suitable for reading contents.

=Remarks=
The purpose of this API is to get the ETL author the fastest access to the file's contents.
It pulls the information out of the message object and partially populates a file object with it.
The database is not called so not all data items of the file object are there.
The following API's are valid on a file object created in this way.

* [[Truxton C API#File IO|File IO]] functions
* [[truxton_file_get_id]]
* [[truxton_file_get_parent_id]]
* [[truxton_file_get_media_id]]
* [[truxton_file_get_depot_id]]
* [[truxton_file_get_depot_length]]
* [[truxton_file_get_depot_offset]]
* [[truxton_file_get_depot_name]]
* [[truxton_file_get_hash]]
* [[truxton_file_get_is_eliminated]]
* [[truxton_file_get_name]]
* [[truxton_file_get_signature]]
* [[truxton_file_get_type]]

=Sample=
<source lang="C" line highlight="29">
#include <TruxtonCAPI.h>

void main( void )
{
char file_id[ 65 ];

uint64_t message = 0;
uint64_t file_handle = 0;
uint64_t app = truxton_etl_create();

truxton_etl_set_application_name( app, "Sample C ETL" );
truxton_etl_set_stage_number( app, 4 );
truxton_etl_add_desired_file_type( app, Type_JPEG );
truxton_etl_set_queue_name( app, "SampleC" );

truxton_etl_set_description( app, "A sample of how to write an ETL");

// Pause here until we get a message from the "SampleC" message queue
message = truxton_etl_get_message( app );

while( message != 0 )
{
// Do something with the message
memset( file_id, 0x00, sizeof( file_id ) );
truxton_message_get_file_id( message, file_id, sizeof( file_id ) );

printf( "Received file id %s\n", file_id );

file_handle = truxton_message_get_file( message );

if ( file_handle != 0 )
{
if ( truxton_file_get_is_eliminated( file_handle ) == 0 )
{
// We've got some contents to play with (DANGER! file could be bigger than RAM!)
uint64_t file_length = truxton_file_get_length( file_handle );
uint8_t * buffer = malloc( file_length );

if ( buffer != NULL )
{
if ( truxton_file_read( file_handle, buffer, file_length ) == file_length )
{
printf( "We successfully read %" PRIu64 " bytes\n", file_length );
}

free(buffer);
}
}
}

truxton_message_destroy( message );

// Pause here until we get another message from the "SampleC" message queue
message = truxton_etl_get_message( app );
}
}
</source>

@@ Line 84: / Line 84: @@
+             }
-             truxton_file_free( file );
+             truxton_file_free( file_handle );
+         }

@@ Line 84: / Line 84: @@
+             }
-             truxton_file_free(file);
+             truxton_file_free( file );
+         }

@@ Line 92: / Line 92: @@
          message = truxton_etl_get_message( app );
+     }
-−
-     truxton_etl_destroy(app);
+     truxton_etl_destroy( app );
+}
 </source>

@@ Line 84: / Line 84: @@
+             }
              truxton_file_free(file);
+         }

@@ Line 83: / Line 83: @@
+                }
+             }
+         }

@@ Line 34: / Line 34: @@
 =Sample=
-<source lang="C" line highlight="29">
+<source lang="C" highlight="29">
 #include <TruxtonCAPI.h>