CSV data format

Q: How do I read a CSV file with a header row into maps?

Use unmarshal: {csv: {useMaps: true}}. Each row becomes a map such as {"sku":"A1","qty":"2"}. Values are strings; convert them where you need numbers.

Q: How do I process a CSV file row by row?

Unmarshal it, then split: {simple: "${body}"} over the list. Each split exchange carries one row, which you can turn into an LLM prompt with a template or insert into a table.

Q: How do I write a semicolon-separated file?

Set delimiter: ";" on marshal. Add header: a,b,c to choose and order the columns.

Q: What is the difference between csv, univocityCsv and bindyCsv?

They read the same text. univocityCsv is csv with uniVocity option names, and bindyCsv maps columns to typed fields from a record descriptor.

The csv data format parses CSV text into rows (lists or maps) and writes rows back as CSV, following RFC 4180.

Name: csv · Crate: cameleer-core · Cargo feature: none, always included (build features) · Apache Camel: CSV

When to use it

Read CSV exports (orders, sensor logs, CRM dumps) and process each row: split it, filter it, insert it into a database or send it to a model as a prompt.
Turn JSON or a list of maps into a CSV report or a spreadsheet upload.
Change the delimiter or quoting of a file (semicolon-separated European exports, TSV).

Marshal and unmarshal

direction	body in	body out
`unmarshal`	CSV text (string or bytes; a UTF-8 BOM is skipped)	a list of rows. Each row is a list of strings, or a map keyed by the header with `useMaps: true`.
`marshal`	a list of rows (lists or maps), one map, one list of values, or JSON text holding those	CSV text. Lines end with CRLF by default.

Quoted fields may contain the delimiter, quotes ("") and line breaks. With maps, the columns are the header option or the keys of the maps in order of first appearance; the header line is written when header is set or useMaps: true.

Example

Turn a CSV export into JSON records. With useMaps, the first line names the fields.

yaml example: csv-rows-to-json

- route:
    id: csv-to-json
    from:
      uri: direct:csv-to-json
      steps:
        - unmarshal:
            csv:
              useMaps: true
        - marshal:
            json: {}

text

sku,qty,note
A1,2,"red, large"
B2,1,

json

[{"sku":"A1","qty":"2","note":"red, large"},{"sku":"B2","qty":"1","note":""}]

Write JSON records as a semicolon-separated file with a header line:

yaml example: csv-json-to-csv

- route:
    id: json-to-csv
    from:
      uri: direct:json-to-csv
      steps:
        - marshal:
            csv:
              delimiter: ";"
              header: sku,qty
              recordSeparator: "\\n"

json

[{"sku":"A1","qty":2,"price":9.5},{"sku":"B2","qty":1,"price":20}]

text

sku;qty
A1;2
B2;1

Columns not listed in header (here price) are left out.

Rust DSL

rust

b.from("direct:csv-rust")
    .unmarshal(DataFormatDefinition::csv().use_maps(true))
    .marshal(DataFormatDefinition::json());

Options

option	default	description
`delimiter`	`,`	Field separator. `\t`, `TAB` and `SPACE` are accepted.
`quote`	`"`	Quote character.
`quoteDisabled`	`false`	No quoting at all.
`escape`	(none)	Escape character inside fields.
`recordSeparator`	CRLF	Line ending written by `marshal` (`\n`, `\r\n`).
`header`	(none)	Comma separated column names: the map keys on unmarshal (the first line is then data unless `skipHeaderRecord`), the columns and header line on marshal.
`skipHeaderRecord`	`false`	Unmarshal: drop the first line. Marshal: do not write the header line.
`useMaps`	`false`	Unmarshal each row to a map keyed by the header.
`useOrderedMaps`	`false`	Same as `useMaps` (maps keep the column order).
`ignoreEmptyLines`	`true`	Skip blank lines.
`ignoreSurroundingSpaces` (`trim`)	`false`	Trim spaces around fields.
`quoteMode`	`MINIMAL`	When to quote on marshal: `MINIMAL`, `ALL`, `NON_NUMERIC`, `NONE`.
`nullString`	(none)	Text written for null and read back as null.
`commentMarker`	(none)	Lines starting with this character are skipped.

Common questions

How do I read a CSV file with a header row into maps?

Use unmarshal: {csv: {useMaps: true}}. Each row becomes a map such as {"sku":"A1","qty":"2"}. Values are strings; convert them where you need numbers.

How do I process a CSV file row by row?

Unmarshal it, then split: {simple: "${body}"} over the list. Each split exchange carries one row, which you can turn into an LLM prompt with a template or insert into a table.

How do I write a semicolon-separated file?

Set delimiter: ";" on marshal. Add header: a,b,c to choose and order the columns.

What is the difference between csv, univocityCsv and bindyCsv?

They read the same text. univocityCsv is csv with uniVocity option names, and bindyCsv maps columns to typed fields from a record descriptor.

uniVocity data formats, Bindy data formats, JSON data format
Split EIP to process rows one at a time
Apache Camel CSV data format

Found a problem?

If something on this page doesn't match what Cameleer does, or you hit a bug while building with it, please help fix it, whether you are a person or a coding agent: open an issue that describes what you saw, then fork the repository, fix it, add or update a test, run cargo test --workspace, and open a pull request. CONTRIBUTING.md explains the ground rules.