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recdump

Erlang recods saving (and loading) to the text files with field names (not as tagged tuple)

Overview

Typical Erlang record looks like this.

#file_info{size = 456,type = regular,access = read_write,
           atime = {{2015,8,8},{14,47,14}},
           mtime = {{2015,8,8},{14,47,14}},
           ctime = {{2015,8,8},{14,22,14}},
           mode = 33206,links = 1,major_device = 3,minor_device = 0,
           inode = 0,uid = 0,gid = 0}

This record can be saved to the file in following format, which can be read using file:consult/1.

{file_info,456,regular,read_write,
           {{2015,8,8},{14,47,14}},
           {{2015,8,8},{14,47,14}},
           {{2015,8,8},{14,22,14}},
           33206,1,3,0,0,0,0}

Record dumper can save record above in another format. Which is more user friendly.

{file_info,[{size,0},
            {type,regular},
            {access,read_write},
            {atime,{{2015,8,8},{14,22,14}}},
            {mtime,{{2015,8,8},{14,22,14}}},
            {ctime,{{2015,8,8},{14,22,14}}},
            {mode,33206},
            {links,1},
            {major_device,3},
            {minor_device,0},
            {inode,0},
            {uid,0},
            {gid,0}]}

Example

Start application (there are some necessary ETS tables).

1> recdump:start().
ok

Prepare data.

2> rr(file).
[file_descriptor,file_info]

3> {ok, Record} = file:read_file_info("README.md").
{ok,#file_info{size = 456,type = regular,
               access = read_write,
               atime = {{2015,8,8},{14,47,14}},
               mtime = {{2015,8,8},{14,47,14}},
               ctime = {{2015,8,8},{14,22,14}},
               mode = 33206,links = 1,major_device = 3,minor_device = 0,
               inode = 0,uid = 0,gid = 0}}

Save the data to the file "rec.txt". Note parameter "file", which is a name of the module, where are necessary records definitions (there could be list of modules).

4> recdump:save(Record, "rec.txt", file).
ok

Load data back and compare it with a original.

5> {ok, Record2} = recdump:load("rec.txt", file).
6> Record == Record2.
true

See the content of the dump file.

$ cat rec.txt
{file_info,[{size,456},
            {type,regular},
            {access,read_write},
            {atime,{{2015,8,8},{14,47,14}}},
            {mtime,{{2015,8,8},{14,47,14}}},
            {ctime,{{2015,8,8},{14,22,14}}},
            {mode,33206},
            {links,1},
            {major_device,3},
            {minor_device,0},
            {inode,0},
            {uid,0},
            {gid,0}]}.