This extension allows you to register all encodings available in the ICU data repository. It supports a total of 1,040 different encodings. The names of the encodings match the <code_set_name> option in each file. It currently only performs encoding when reading data, converting from <code_set_name> to UTF-8.

Usage

To use this extension, you must first install and load it in DuckDB.

INSTALL encodings;
LOAD encodings;

After that, all encodings are initialized in your database instance. To use them, simply refer to the correct encoding.

FROM read_csv('my_shift_jis.csv', encoding = 'shift_jis')

Building

Generating Encoding Maps

Most of the code in this library consists of auto-generated maps from the Unicode data. The Unicode data is inlined in the third_party folder, and the generated code resides in src/include/generated and src/generated . Any changes to files in these folders should be made by modifying the scripts/converter.py script, rather than editing the files manually. If it's necessary to regenerate the code (e.g., due to a bug fix in the replacement maps), simply run:

python scripts/converter.py

Note that the script does not generate formatted code, so you must also run:

make format

It is also important to notice that the scripts/converter.py script also generates the test/sql/encodings.test test file.

Build steps

Now to build the extension, run:

make

The main binaries that will be built are:

./build/release/duckdb
./build/release/test/unittest
./build/release/extension/encodings/encodings.duckdb_extension

duckdb is the binary for the duckdb shell with the extension code automatically loaded.
unittest is the test runner of duckdb. Again, the extension is already linked into the binary.
encodings.duckdb_extension is the loadable binary as it would be distributed.

Running the tests

Different tests can be created for DuckDB extensions. The primary way of testing DuckDB extensions should be the SQL tests in ./test/sql. These SQL tests can be run using:

make test

Installing the deployed binaries

To install your extension binaries from S3, you will need to do two things. Firstly, DuckDB should be launched with the allow_unsigned_extensions option set to true. How to set this will depend on the client you're using. Some examples:

CLI:

duckdb -unsigned

Python:

con = duckdb.connect(':memory:', config={'allow_unsigned_extensions' : 'true'})

NodeJS:

db = new duckdb.Database(':memory:', {"allow_unsigned_extensions": "true"});

Secondly, you will need to set the repository endpoint in DuckDB to the HTTP url of your bucket + version of the extension you want to install. To do this run the following SQL query in DuckDB:

SET custom_extension_repository='bucket.s3.eu-west-1.amazonaws.com/<your_extension_name>/latest';

Note that the /latest path will allow you to install the latest extension version available for your current version of DuckDB. To specify a specific version, you can pass the version instead.

After running these steps, you can install and load your extension using the regular INSTALL/LOAD commands in DuckDB:

INSTALL encodings
LOAD encodings