Req.Decode (req v0.8.0-rc.0)

Decodes response body based on the detected format.

To decode other formats, or to add support for custom ones, use the :decoders option.

Built-in decoders

Format	Decoder	Enabled	Streaming Decoding
`:json`, `:json_api`	`Req.JSON`	✓
`:ndjson`	`Req.NDJSON`	✓	✓
`:sse`	`Req.SSE`	✓	✓
`:zip`	`Req.ZIP`
`:tar`, `:tgz`	`Req.Tar`
`:gz`	`Req.Gzip`		✓
`:zst`	`Req.Zstd` (requires Erlang/OTP 28+)		✓
`:csv`	`Req.CSV` (requires nimble_csv)

The format is determined by the response content-type header. See MIME for registering content-type/format mapping.

Decompression Bombs

The archive and compression decoders (:zip, :tar, :tgz, :gz, and :zst) decompress the whole response body into memory with no size limit, so a small response can expand to many gigabytes. For this reason they are not enabled by default; only opt into them via the :decoders option for endpoints you trust.

Request Options

:decoders - the list of decoders to use. Defaults to [:json, :json_api, :ndjson, :sse].
Each element is either:
- a format (atom) handled by a built-in decoder, e.g. :json or :zip;
- a {format, decoder} or {content_type, decoder} tuple, where format is an atom e.g.: :json, content_type is a binary e.g.: application/x-amz-json-1.0, and decoder is one of:
  - another format (atom), to reuse a built-in decoder, e.g. decoders: [json5: :json].
  - a 1-arity function that returns {:ok, term} or {:error, exception}, e.g.:
```
decoders: [{"text/calendar", &{:ok, ICal.from_ics(&1)}}]
```
Setting :decoders replaces the default, so include :json if you still want JSON decoded:
```
# handles json, zip, and tar:
Req.new(decoders: [:json, :zip, :tar])
```
Set :decoders to false to disable all decoding, including JSON.
:decode_body - if set to false, disables automatic response body decoding. Defaults to true.
:raw - if set to true, disables response body decoding. Defaults to false.
Note: setting raw: true also disables response body decompression.

Examples

Decode JSON:

iex> response = Req.get!("https://httpbingo.org/json")
...> response.body["slideshow"]["title"]
"Sample Slide Show"

Decode a ZIP archive (opt-in):

iex> response = Req.get!("https://example.com/archive.zip", decoders: [:zip])
...> response.body["file.txt"]
"contents"