



= CSV Module

Read CSV files and use them in maps.

The CSV files MUST be formatted according to `https://tools.ietf.org/html/rfc4180[RFC 4180]`.

WARNING: Multi-line fields are NOT allowed.

The CSV map can be used in a `map` section, as in the following example.

  map csv &User-Name {
  }

The argument to "map" is dynamically expanded.  The result is taken
as a string, and is used as the value of the "key".  The key is
then looked up in the cached CSV file.  The fields are then mapped
to the attributes on the left side of the map.

## Configuration Settings


filename:: The file which contains the CSV data.



delimiter:: The field delimiter. MUST be a one-character string.



header:: Whether or not there is a one-line header in the file.

If the value is set to 'yes', then the CSV file MUST contain
a header as the first line of the file.  That header line
must contain the field names.



allow_multiple_keys:: Whether the file can have multiple entries
which match the same key.

The default is `no`.

If set to `yes`, then multiple entries are allowed.  When a
key matches, each entry is applied in the order it appears
in the file.



fields:: A string which defines field names.

This configuration item is used only when `header = no`.
The content of the `fields` item must be the same as in https://tools.ietf.org/html/rfc4180[RFC 4180].
That is, a list of field names, separated by the `delimiter`
character.

The `csv` module can be used to read files such as `/etc/group`
By setting `delimiter = ":"`, and by using `fields = "group:::,user"`

The special character `,` can be used *only* for the `key`
field, and *only* if the `key` field is the last field.
This special syntax means "add multiple entries for this
line, one for each `key`".

[NOTE]
=====
  * the header MUST have the same number of fields as are in the CSV file.
  * the field names MUST NOT include whitespace.
  * Fields which are not used should have no name

e.g. *"foo,,bar"* defines 3 fields, where the second is unused.
=====


index_field:: The name of the field which is used to index the
entries.

It can be any one of the field names defined above.

The CSV rows are normally placed into a binary tree,
indexed by this field.  A binary tree allows for fast
lookups, no matter the size of the CSV file.

When looking up entries in the binary tree, the key must match
the `index_field` exactly.

If `data_type` is an IP address type, then the CSV rows are
placed into a prefix trie, indexed by this field.  The
prefix trie allows for fast prefix lookups.

When looking up entries in a prefix trie, the closest
enclosing prefix is matched.  This prefix match allows you
to place `192.0.2/24` as an index field in the file, and
then lookups of `192.0.2.1` will return that row.



key:: The key string used to look up entries via the `index_field`.

When the `csv` module is listed in a processing section,
the `key` is used to find the appropriate entry.  The `update`
section below is then applied.

The data type of the key is used to determine the type
of structure used to store the `index_field` values.

When the key data type is one of: `ipaddr`, `ipv4prefix`,
`ipv6addr`, or `ipv6prefix`, then the rows are stored in a
prefix trie.

For all other key data types, the rows are stored in a binary
tree.

If a data type other than the native type of `key` expression
is needed, the casting operator can be used.
For example:
a key value of `<ipv4prefix>&reply.Reply-Message`.
would result in a prefix trie being used for lookups, and the
`string` value of the `link:https://freeradius.org/rfc/rfc2865.html#Reply-Message[Reply-Message]` attribute being parsed as
CIDR notation.

Note that the individual fields of the CSV file do not have
data types.  They are stored internally as strings, and are
parsed to the final data type only when the `csv` module
is run, either in-place, or as a `map`.



### Mapping of CSV fields to attributes.

WARNING: Although this format is almost identical to the `unlang`
update section format, it does *NOT* mean that you can use other
`unlang` constructs in module configuration files.

Configuration items are in the format:

  <fr attr> <op> <csv field>

Where:

[options="header,autowidth"]
|===
| Parameter   | Description
| <fr attr>   | Is the destination RADIUS attribute
                with any valid list and request qualifiers.
| <op>        | Is any assignment attribute (=, :=, +=, -=).
| <csv field> | Is the name of a field from the CSV file, as taken
                from the `fields` configuration item.
|===

Request and list qualifiers may be placed after the `update`
section name to set default destination requests/lists
for `<fr attr>s` with no list qualifiers.

NOTE: CSV field names should be single quoted unless you want
the name to be derived from an xlat expansion, or an attribute ref.

update { ... }::



The module also exports a `map` expansion, via the syntax:

map cvs <key> { ... }

Where `csv` is the name of the module, and `key` is an expansion
as given the the key` field above.  For example, the map could
look like this:

map csv &User-Name {
  &reply.Reply-Message := 'color'
  &Tmp-Integer-0 := 'count'
}

This map does the same operations as the key / update
fields given above.  The benefit here is that the key can
be dynamically changed, depending on the needs of the
current section.

If the key is not found in the CSV file, then the `map`
does nothing.


== Default Configuration

```
#		Attribute-Name := field1
#		Attribute-Name := field2
#		...
csv {
	filename = ${modconfdir}/csv/${.:instance}
	delimiter = ","
	header = no
	allow_multiple_keys = no
	fields = "name,size,color,count"
	index_field = "name"
	key = &User-Name
	update reply {
	       &Reply-Message := 'color'
	       &Tmp-Integer-0 := 'count'
	}
}
```
