More information related to EXIF is here.
- Erlang/OTP 18 or higher.
To build the application and run the test suite, use the Makefile like so:
$ make
$ make test
To add erlang_exif as a dependency to your rebar-based project, simply add the following to your
rebar.config file, then run the ./rebar3 upgrade command to retrieve it.
{deps, [
{erlang_exif, "3.0.0"}
]}.
The erlang_exif:read(Path) function actually calls erlang_exif:read(Path, map).
The erlang_exif:read(Path, ReturnType) function returns {ok, Exif} where Exif is a dict:dict() or a map
of the values read from the JPEG image. ReturnType has two valid values: dict and maps.
If no such values are present, the structure will be empty.
However, if there was an error, an {error, Reason} tuple will be returned, where Reason is nearly always invalid_exif.
case erlang_exif:read(Path, dict) of
{error, Reason} ->
error_logger:error_msg("Unable to read EXIF data from ~s, ~p~n", [Path, Reason]);
{ok, ExifData} ->
case dict:find(date_time_original, ExifData) of
{ok, Original} ->
% do something with the date...
ok;
error ->
error_logger:info_msg("No original date available")
end
end.
Two more functions are present: erlang_exif:read_binary/1 and erlang_exif:read_binary/2 which are
equivalents of erlang_exif:read/1,2.
They accept actual file in binary format as a first argument, instead of a path.