PISTON-1170: Sets content_type for prepend_on_forward correctly.

The kzm_message:forward_message/4 function branches, depending on whether the user has recorded an additional message to be prepended to the voicemail message being forwarded. Prepending the additional message requires the two media files to be merged into a temporary file. This is then written to the database as an attachment.

Prior to this fix, the code assumed that the merged media file has an mp3 format, which is not necessarily true. In addition, it did not pass any content-type option to the kz_datamgr:put_attachment/5 function which actually writes the attachment. As a result, the attachment metadata in the database always indicated a content-type of application/octet-stream.

Calls to kz_media_util:join_media_files/2 now ensure that the merged output format is specified explicitly, rather than relying on default behaviour. The same format is also mapped to the corresponding MIME type which is passed to kz_datamgr:put_attachment/5 to ensure the attachment metadata is correct.

Upstream pull requests:
4.3: 2600hz#6674
5: https://github.com/2600hz/kazoo-core/pull/170

core/kazoo_media/include/kz_media.hrl

@@ -1,6 +1,7 @@
 -ifndef(KZ_MEDIA_HRL).
 
 -define(CHUNKSIZE, 24576).
+-define(NORMALIZATION_FORMAT, kapps_config:get_ne_binary(<<"crossbar.media">>, <<"normalization_format">>, <<"mp3">>)).
 
 -record(media_file, {stream_url = <<>> :: binary()
                     ,contents = <<>> :: binary()

core/kazoo_media/src/kz_media_util.erl

@@ -45,8 +45,6 @@
 -define(NORMALIZE_SOURCE_ARGS, kapps_config:get_binary(?CONFIG_CAT, <<"normalize_source_args">>, <<>>)).
 -define(NORMALIZE_DEST_ARGS, kapps_config:get_binary(?CONFIG_CAT, <<"normalize_destination_args">>, <<"-r 8000">>)).
 
--define(NORMALIZATION_FORMAT, kapps_config:get_ne_binary(<<"crossbar.media">>, <<"normalization_format">>, <<"mp3">>)).
-
 -define(USE_ACCOUNT_OVERRIDES, kapps_config:get_is_true(?CONFIG_CAT, <<"support_account_overrides">>, 'true')).
 
 -define(DEFAULT_MAX_RECORDING_LIMIT, 3*?SECONDS_IN_HOUR).

core/kazoo_voicemail/src/kvm_message.erl

@@ -18,6 +18,7 @@
         ]).
 
 -include("kz_voicemail.hrl").
+-include("kazoo_media/include/kz_media.hrl").
 
 -export_type([vm_folder/0]).
 -export_type([db_ret/0]).
@@ -786,32 +787,35 @@ prepend_forward_message(Call, ForwardId, Metadata, _SrcBoxId, Props) ->
     {'ok', _} = kz_media_util:synthesize_tone(OrigSampleRate, <<"440">>, <<"0.5">>, TonePath),
 
     lager:debug("joining prepend to original message"),
-    case kz_media_util:join_media_files([TmpPath, TonePath, OrigPath], [{sample_rate, OrigSampleRate}]) of
+    JoinFormat = ?NORMALIZATION_FORMAT,
+    JoinOptions = [{'sample_rate', OrigSampleRate}, {'to_format', JoinFormat}],
+    case kz_media_util:join_media_files([TmpPath, TonePath, OrigPath], JoinOptions) of
         {'ok', FileContents} ->
-            JoinFilename = <<(kz_binary:rand_hex(16))/binary, ".mp3">>,
+            JoinFilename = <<(kz_binary:rand_hex(16))/binary, ".", JoinFormat/binary>>,
+            FileProps = [{'content_type', kz_mime:from_extension(JoinFormat)}],
             _ = [kz_util:delete_file(F) || F <- [TmpPath, OrigPath, TonePath]],
             %%TODO: update forwarded doc with length and media_filename
-            try_put_fwd_attachment(AccountId, ForwardId, JoinFilename, FileContents, 3);
+            try_put_fwd_attachment(AccountId, ForwardId, JoinFilename, FileContents, FileProps, 3);
         {'error', _} ->
             _ = [kz_util:delete_file(F) || F <- [TmpPath, OrigPath, TonePath]],
             lager:warning("failed to join forward message media files"),
             {'error', 'join_failed'}
 
     end.
 
--spec try_put_fwd_attachment(kz_term:ne_binary(), kz_term:ne_binary(), kz_term:ne_binary(), iodata(), 1..3) -> db_ret().
-try_put_fwd_attachment(AccountId, ForwardId, _JoinFilename, _FileContents, 0) ->
+-spec try_put_fwd_attachment(kz_term:ne_binary(), kz_term:ne_binary(), kz_term:ne_binary(), iodata(), kz_term:proplist(), 1..3) -> db_ret().
+try_put_fwd_attachment(AccountId, ForwardId, _JoinFilename, _FileContents, _FileProps, 0) ->
     lager:error("max retries to save prepend forward voicemail attachment ~s in db ~s"
                ,[ForwardId, kvm_util:get_db(AccountId, ForwardId)]
                ),
     {'error', 'max_save_retries'};
-try_put_fwd_attachment(AccountId, ForwardId, JoinFilename, FileContents, Loop) ->
-    case kz_datamgr:put_attachment(kvm_util:get_db(AccountId, ForwardId), ForwardId, JoinFilename, FileContents) of
+try_put_fwd_attachment(AccountId, ForwardId, JoinFilename, FileContents, FileProps, Loop) ->
+    case kz_datamgr:put_attachment(kvm_util:get_db(AccountId, ForwardId), ForwardId, JoinFilename, FileContents, FileProps) of
         {'ok', _}=OK -> OK;
         {'error', 'conflict'} ->
-            try_put_fwd_attachment(AccountId, ForwardId, JoinFilename, FileContents, Loop - 1);
+            try_put_fwd_attachment(AccountId, ForwardId, JoinFilename, FileContents, FileProps, Loop - 1);
         {'error', 'timeout'} ->
-            try_put_fwd_attachment(AccountId, ForwardId, JoinFilename, FileContents, Loop - 1);
+            try_put_fwd_attachment(AccountId, ForwardId, JoinFilename, FileContents, FileProps, Loop - 1);
         {'error', _Reason}=Error ->
             lager:error("failed to save prepend forward voicemail message ~s in db ~s : ~p"
                        ,[ForwardId, kvm_util:get_db(AccountId, ForwardId), _Reason]),