Plugin: ini

• infos = Information about the ini plugin is in keys below
• infos/author = Thomas Waser thoma.nosp@m.s.wa.nosp@m.ser@l.nosp@m.ibel.nosp@m.ektra.nosp@m..org
• infos/licence = BSD
• infos/needs =
• infos/provides = storage/ini
• infos/recommends = binary
• infos/placements = getstorage setstorage
• infos/status = unittest shelltest nodep libc configurable
• infos/metadata = order
• infos/description = storage plugin for INI files

Introduction

This plugin allows Elektra's users to read and write INI files. INI files consist of simple key value pairs of the form key=value. Additionally keys can be categorized into different sections. Sections must be enclosed in "[]", for example "[section]". Each section is converted into a directory key (without value) and keys below the section are located below the section key. If the same section appears multiple times, the keys of all sections with the same name are merged together under the section key.

On the one hand the ini plugin is feature rich and customizable, on the other hand it is quite buggy and shows unexpected behavior in some of its features.

Usage

If you want to add an INI file to the global key database, simply use mount:

sudo kdb mount file.ini user/tests/ini ini

Then you can modify the contents of the INI file using set:

kdb set user/tests/ini/key value
#> Create a new key user/tests/ini/key with string "value"
kdb set user/tests/ini/section
#> Create a new key user/tests/ini/section with null value
kdb set user/tests/ini/section/key value
#> Create a new key user/tests/ini/section/key with string "value"

Find out which file you modified:

kdb file user/tests/ini
# STDOUT-REGEX: .+/file.ini
 
# Undo modifications
kdb rm -r user/tests/ini
sudo kdb umount user/tests/ini

Comments

The ini plugin supports the use of comments. Comment lines start with a ';' or a '#'. Comments are put into the comment metadata of the key following the comment. This can be either a section key or a normal key. When creating new comments (e.g. via kdb meta-set) you can prefix your comment with the comment indicator of your choice (';' or '#') which will be used when writing the comment to the file. If the comment is not prefixed with a comment indicator, the ini plugin will use the character defined by the comment option, or default to '#'.

Multi-Line Support

The ini plugin supports multiline values. Continuations of previous values have to start with whitespace characters.

For example consider the following INI file:

key1=value1
key2=value2
        with continuation
        lines

This would result in a KeySet containing two keys. One key named key1 with the value value1 and another key named key2 with the value value2\nwith continuation\nlines.

By default this feature is enabled. The default continuation character is tab (\t). If you want to use another character, then please specify the configuration option linecont.

Arrays

The ini plugin handles repeating keys by turning them into an elektra array when the array config is set.

For example an INI file looking like:

[sec]
a=1
a=2
a=3
a=4

will be interpreted as

/sec
/sec/a
/sec/a/#0
/sec/a/#1
/sec/a/#2
/sec/a/#3

The following example shows how you can store and retrieve array values using the ini plugin.

# Mount the INI plugin with array support
sudo kdb mount config.ini user/tests/ini ini array=true
 
# Add an array storing song titles
kdb set user/tests/ini/songs/#0 "Non-Zero Possibility"
kdb set user/tests/ini/songs/#1 "Black Art Number One"
kdb set user/tests/ini/songs/#2 "A Story Of Two Convicts"
 
# Check if INI saved all array entries
kdb ls user/tests/ini/songs
#> user/tests/ini/songs
#> user/tests/ini/songs/#0
#> user/tests/ini/songs/#1
#> user/tests/ini/songs/#2
 
# Retrieve an array item
kdb get user/tests/ini/songs/#2
#> A Story Of Two Convicts
 
# Check the file written by the INI plugin
kdb file user/tests/ini | xargs cat
#> songs=Non-Zero Possibility
#> songs=Black Art Number One
#> songs=A Story Of Two Convicts
 
# Undo modifications
kdb rm -r user/tests/ini
sudo kdb umount user/tests/ini

Binary Data

By default the INI plugin does not support binary data. You can use the Base64 plugin to remove this limitation.

```

Mount INI and recommended plugin Base64

We add the required plugin <tt>base64</tt> (which provides <tt>binary</tt>) at the end too,

since otherwise this command leaks memory.

sudo kdb mount –with-recommends config.ini user/tests/ini ini base64

Add empty binary value

printf 'nothing="@BASE64"
' > kdb file user/tests/ini

Copy binary data

kdb cp system/elektra/modules/ini/exports/get user/tests/ini/binary

Add textual data

kdb set user/tests/ini/text 'Na na na na na na na na na na na na na na na na Batman!'

Print empty binary value

kdb get user/tests/ini/nothing #>

Print binary data

kdb get user/tests/ini/binary

STDOUT-REGEX: ^(\x[0-9a-f]{1,2})+$

Print textual data

kdb get user/tests/ini/text #> Na na na na na na na na na na na na na na na na Batman!

kdb rm -r user/tests/ini sudo kdb umount user/tests/ini

## Metadata
 
The INI plugin also supports to store arbitrary metadata in comments after the `@META` declarative.

sudo kdb mount config.ini user/tests/ini ini

Add a new key and some metadata

kdb set user/tests/ini/brand new kdb meta-set user/tests/ini/brand description "The Devil And God Are Raging Inside Me" kdb meta-set user/tests/ini/brand rationale "Because I Love It"

The plugin stores metadata as comments inside the INI file

kdb file user/tests/ini | xargs cat #> #@META description = The Devil And God Are Raging Inside Me #> #@META rationale = Because I Love It #> brand=new

Retrieve metadata

kdb meta-ls user/tests/ini/brand | grep -v 'internal'

rationale

description

kdb meta-get user/tests/ini/brand description #> The Devil And God Are Raging Inside Me kdb meta-get user/tests/ini/brand rationale #> Because I Love It

The plugin ignores some metadata such as <tt>comment</tt>!

kdb meta-set user/tests/ini/brand comment "Where Art Thou?" kdb meta-get user/tests/ini/brand comment

STDERR: Metakey not found

RET: 2

kdb rm -r user/tests/ini sudo kdb umount user/tests/ini ```

Sections

The ini plugin supports 3 different sectioning modes (via section=):

• NONE sections wont be printed as [Section] but as part of the key name section/key
• NULL only empty keys will be printed as [Section]
• ALWAYS sections will be created automatically. This is the default setting:

sudo kdb mount /empty.ini dir/tests ini
kdb set dir/tests/a/b ab
kdb get dir/tests/a       # <-- key is suddenly here
cat empty.ini
#> [a]
#> b=ab
 
# Undo modifications
kdb rm -r dir/tests
sudo kdb umount dir/tests

By changing the option section you can suppress the automatic creation of keys. E.g., if you use NULL instead you only get a section if you explicitly create it:

sudo kdb mount /empty.ini dir/tests ini section=NULL
kdb set dir/tests/a/b ab
kdb get dir/tests/a       # no key here
# RET: 11
cat empty.ini
#> a/b=ab
kdb rm dir/tests/a/b
kdb set dir/tests/a    # create section first
kdb set dir/tests/a/b ab
cat empty.ini
#> [a]
#> b=ab
 
# Undo modifications
kdb rm -r dir/tests
sudo kdb umount dir/tests

Merge Sections

The ini plugin supports merging duplicated section entries when the mergesections config is set. The keys will be appended to the first occurrence of the section key.

Ordering

The ini plugin preserves the order. Inserted subsections get appended to the corresponding parent section and new sections by name.

Example:

sudo kdb mount test.ini /tests/ini ini
 
cat > `kdb file /tests/ini` <<EOF \
[Section1]\
key1=val1\
[Section3]\
key3=val3\
EOF
 
kdb file /tests/ini | xargs cat
#> [Section1]
#> key1=val1
#> [Section3]
#> key3=val3
 
kdb set /tests/ini/Section1/Subsection1/subkey1 subval1
kdb set /tests/ini/Section2/key2 val2
kdb file /tests/ini | xargs cat
#> [Section1]
#> key1=val1
#> [Section1/Subsection1]
#> subkey1=subval1
#> [Section2]
#> key2=val2
#> [Section3]
#> key3=val3
 
# Undo modifications
kdb rm -r /tests/ini
sudo kdb umount /tests/ini

The current implementation of the ordering sometimes breaks compatibility with the cache plugin (see ini bug).

Special Characters

The INI plugin also supports values and keys containing delimiter characters (=) properly.

``` sudo kdb mount test.ini user/tests/ini ini

printf '[section1]
' > kdb file user/tests/ini printf 'hello=world
' >> kdb file user/tests/ini

kdb get user/tests/ini/section1/hello #> world

kdb set user/tests/ini/section1/x=x 'a + b=b + a' kdb get user/tests/ini/section1/x=x #> a + b=b + a

Undo modifications

kdb rm -r user/tests/ini sudo kdb umount user/tests/ini ```