async_read

NAME

async_read() - read a file into a string then executes a callback

SYNOPSIS

void async_read( string file, function callback );
promise async_read( string file );

DESCRIPTION

Read  a  line  of text from a file into a string.  Normally, read_file
takes a second and third arguments for start_line and number_of_lines to
read, but async_read will return the entire file to the callback.

The callback should follow this format:

    function(mixed res) {
        // -1 for file not read
        // string file contents otherwise
    }


With the callback OMITTED, returns a promise instead: fulfilled with
the file's contents, or rejected with the negative int the callback
would have received on failure. Inside an async function:

    string s = await async_read( "/log/access" );

NOTE

When the 'this_player in call_out' driver setting is enabled,
this_player() inside the callback is preserved from the time the
request was made, like call_out().

SEE ALSO

file_size(3), read_buffer(3), read_file(3), write_file(3), async_write(3),
valid_read(4), valid_write(4)