Elektra: README

Elektra 0.8.14

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README

- infos = Information about ini plugin is in keys below
- infos/author = Felix Berlakovich elekt.nosp@m.ra@b.nosp@m.erlak.nosp@m.ovic.nosp@m.h.net
- infos/licence = BSD
- infos/needs =
- infos/provides = storage
- infos/placements = getstorage setstorage
- infos/description = ini file backend

This plugin allows read/write of INI files. INI files consist of simple key value pairs of the form "key = value". Additionally keys can be categorised 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.

## USAGE

If you want to add a ini file to the global key database, simply use mount:

    kdb mount file.ini /example ini

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

    kdb set user/example/key value
    kdb set user/example/section
    kdb set user/example/section/key value

Find out which file you modified:

    kdb file user/example

## SECTIONS

When converting a KeySet to an INI file it is important to differentiate between regular keys and section keys. The ini plugin treats all keys with a binary NULL value as section key. Note that binary NULL is not the same as an empty value (i.e. "").

For example consider the following ini file:

                                [section1]
                                key1 =
                                key2 = value2

This would result in a KeySet containing three keys. The section key `section1` would be a binary key with value NULL (i.e. 0). `section1/key1` would be a regular key with value "". `section1/key2` would be a regular key with value "value2". In the other direction this requires section keys to be manually created with a binary NULL value.

For example consider the following KeySet:

                                section1 = ""
                                section1/subkey = "value1"

Although section1 might look like a section, it would result in the following ini file:

                                section1 =
                                section1\/subkey = value1

### AUTOSECTIONS

Creating the section keys manually can be cumbersome. This is especially true because KeySets resulting in INI files usually do not contain keys with a depth greater than 1 relative to the parent key. For that reason a good guess can be made what should be sections and what not. This is done by activanting the autosections option.

The autosections feature can be enabled by creating a key named `autosections` in the configuration of the plugin. Note that only the existence of the key is relevant, not its value.

As soon as this key exists, the plugin will automatically create section keys for keys with a depth greater than 1 relative to the parent key.

For example consider the following ini file:

                                [section1]
                                key1 =
                                key2 = value2
                                [section2]
                                key3 = value3

Without the autosections option the following KeySet is required to create this ini file:

                                parent/section1 = NULL
                                parent/section1/key1 = ""
                                parent/section1/key2 = "value2"
                                parent/section2 = NULL
                                parent/section2/key3 = "value3"

The section keys have to be inserted manually. With the autosections option the KeySet can be reduced to the following:

                                parent/section1/key1 = ""
                                parent/section1/key2 = "value2"
                                parent/section2/key3 = "value3"

All three keys have a depth greater than 1 relative to the parent key `parent`. Therefore the key name part directly below the parent key is considered to be the section name. For example, for the keys `parent/section1/key1` and `parent/section1/key2` `section1` is considered to be the section and is automatically created in the INI file.

## COMMENTS

The ini plugin supports the use of comments. Comment lines start with a ';' or a '#'. Adjacent comments are merged together (separated by "\n") and are put into the comment metadata of the key following the comment. This can be either a section key or a normal key.

## MULTILINE SUPPORT

The ini plugin supports multiline ini 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 the support for multiline values is disabled because formatting (whitespaces before keynames) may be accidentially mixed with value continuations. The multiline support can be enabled by creating a key named `multiline` in the configuration of the plugin. Note that only the existence of the key is relevant, not its value. As soon as this key exists, the plugin treats lines starting with whitespaces as continuations of the previous key value. Keep in mind, that writing multiline values is also only supported if the multiline support is turned on. Otherwise the plugin will refuse to write key values with newlines.

## METAKEY SUPPORT

The ini plugin supports turning keys into metakeys by adding the config key `meta`.

## PRESERVE ORDER

If the `preserveorder` config key is set, the ini plugin preserves the original order of the file. Only use this option for editing existing key values.

## RESTRICTIONS

Currently the plugin has the following shortcomings:

- formatting newlines are not restored on write
- regardless of which comment was used originally, it is always written back as ';'
- Using square brackets (`[` and `]`) in sections is not possible
- Using `=` in key names is not possible

The plugin is still work in progress.